Book VI (part 2 of 3)

Book VI (part 2 of 3)

=A.D. 1788.=--Barthélémy (Jean Jacques), who, after completing his studies in a French seminary of Jesuits, succeeded Gros de Boze as keeper of the king’s cabinet of medals, publishes in four volumes, at Paris, the first edition of his “Voyage du Jeune Anacharsis.” In this well-known work, begun by him in 1757, and translated into English under the title “Travels of Anacharsis the Younger in Greece,” Barthélémy alludes to the possibility of telegraphing by means of clocks (pendules, not horloges), having hands similarly magnetized in conjunction with artificial magnets. These were “presumed to be so far improved that they could convey their directive power to a distance, thus, by the sympathetic movements of the hands or needles in connection with a dial alphabet, communications between distant friends could be carried on.”

Writing to Mme. du Deffand in 1772, he observes:

“It is said that with two timepieces the hands of which are magnetic, it is enough to move one of these hands to make the other take the same direction, so that by causing one to strike twelve the other will strike the same hour. Let us suppose that artificial magnets were improved to the point that their virtue could communicate itself from here to Paris; you have one of these timepieces, we another of them; instead of hours we find the letters of the alphabet on the dial. Every day at a certain hour we turn the hand, and M. Wiard [Mme. du Deffand’s secretary] puts together the letters and reads.... This idea pleases me immensely. It would soon be corrupted by applying it to spying in armies and in politics, but it would be very agreeable in commerce and in friendship.”

REFERENCES.--“Correspondance inédite de Mad. Du Deffand,” Vol. II. p. 99; letter of J. MacGregor in Journal Society of Arts, May 20, 1859, pp. 472, 473.

=A.D. 1789.=--Adriaan Paets Van Troostwÿk and Jean Rodolphe Deimann, Dutch chemists, associated for the purpose of scientific research, complete the experiments of Lord Cavendish and announce, in the Journal de Physique, their discovery of the decomposition of water through the electric spark, which latter is conveyed by means of very fine gold wires. As is now well known, water is by this means resolved into its two elements of oxygen and hydrogen, both of which assume their gaseous form.

The electric machine they employed was a very powerful double-plate one, of the Teylerian mode of construction, causing the Leyden jar to discharge itself twenty-five times in fifteen revolutions.

REFERENCES.--“Mém. de la Soc. de Phys. Exp. Rotterdam,” Tome VIII; Journal de Physique, Vol. XXXIII; Noad, “Manual,” p. 161; “Encyl. Brit.,” Vol. VIII, 1855, pp. 530, 565; “Biog. Universelle,” Vol. X. p. 282; De La Rive, “Electricity,” Vol. II. p. 443; Wm. Henry, “Elements of Experimental Chemistry,” London, 1823, Vol. I. pp. 251, 252; Delaunay’s “Manuel,” etc., 1809, pp. 180–183; “Verhandl. van het Genootsch te Rotterdam” (“Mém. de la Soc. de Phys. Exp. de Rotterdam”) Vol. VIII; Poggendorff, Vol. I. p. 1555; Dove, p. 243; G. Carradori (Brugnatelli’s Annali di chimica, Vol. I. p. 1); John Cuthbertson, “Beschreibung einer Elekt. ...” Leipzig, 1790.

=A.D. 1790.=--Reveroni--Saint-Cyr (Jacques Antoine, Baron de), French Colonel and author, best known by his very interesting work, “Mécanismes de la Guerre,” proposes an electric telegraph for the purpose of announcing the drawings of lottery numbers; no satisfactory information as to its construction, however, appears obtainable.

REFERENCES.--Fahie, “History,” etc., London, 1884, p. 96; Etenaud, “La Télégraphie Electrique,” 1872, Vol. I. p. 27; _Sc. Am. Supp._, No. 384, pp. 6, 126.

=A.D. 1790.=--Mr. Downie, master of his Majesty’s ship “Glory,” makes a report on local attraction wherein he observes “that in all latitudes, at any distance from the magnetic equator, the upper ends of iron bolts acquire an opposite polarity to that of the latitude,” an observation, Harris remarks, which accords with Marcel’s experiment (at A.D. 1702).

“I am convinced,” says Mr. Downie, “that the quantity and vicinity of iron, in most ships, has an effect in attracting the needle; for it is found by experience that the needle will not always point in the same direction when placed in different parts of a ship; also, it is very easily found that two ships, steering the same course by their respective compasses, will not go exactly parallel to each other; yet when their compasses are on board the same ship they will agree exactly.”

REFERENCES.--William Walker, “The Magnetism of Ships,” London, 1853, p. 20; J. Farrar, “Elements,” p. 376; Harris, “Rudim. Magn.,” 1852, Part III. p. 161.

=A.D. 1790.=--Tralles (Johann Georg), a German scientist, is the first to make known the negative electricity of cascades. This he communicates through his “Uber d. Elektricität d. Staubbachs,” published at Leipzig.

In the Report on Atmospheric Electricity of Francis J. F. Duprez, translated from the Memoirs of the Royal Academy of Brussels by Dr. L. D. Gale, we read that one day while in the Alps, opposite the cascade of Staubbach, near Lauterbrunnen, Tralles “presented his atmospheric electrometer, not armed with the metallic wire, to the fine spray which resulted from the dispersion of the water. He immediately obtained very distinct signs of negative electricity. The same effect was exhibited at the cascade of Reichenbach. Volta, a short time after, verified the correctness of this observation, not only above the great cascades, but also wherever a fall of water existed, however small, provided the intervention of the wind caused the dispersion of the drops. The electricity always appeared to him, as it did to Tralles, negative. Schübler repeated the same experiments in his journey to the Alps in 1813. He observed farther, that this negative electricity was very strong, since it became perceptible at a distance of 300 feet from the cascade of Reichenbach; and at a distance of 100 feet his electrometer indicated 400 and even 500 degrees.... Tralles attributed it at first to the friction of the minute drops of water against the air; but soon after he thought, with Volta, that the cause was to be found in the evaporation which the same minute drops experience in falling....”

The Italian physicist, Giuseppe Belli, who published at Milan, during 1836, “Sulla Elettricità negativa delle cascate,” entertains an opinion contrary to that advanced by M. Becquerel, and believes “that the electrical phenomenon of the water of cascades is owing to the development of electricity by the induction which the positive electricity of the atmosphere exercises on the water. The water, he says, is by induction in the negative state, when the atmosphere is, as it is ordinarily, charged with positive electricity. At the moment when this water divides into thousands of minute drops, it cannot fail to carry the electricity with which the electrical induction of the atmosphere has impregnated it to all bodies which it meets.”

REFERENCES.--“Œuvres de Volta,” Vol. II. p. 239; Franz Samuel Wilde, “Expériences sur l’électricité des cascades” (“Mémoires de Lausanne,” Vol. III, “Histoire,” p. 13, 1790); “Bibliographie Universelle,” N. S., 1836, Vol. VI. p. 148; Houzeau et Lancaster, “Bibl. Générale,” Vol. II. p. 265; “Biblio. Ital.,” LXXXIII. p. 32; Schweigger, Journal f. Chemie u. Physik, Vol. IX. p. 358; Tralles, “Beyträge zur Lehre von der Electricität”; L. W. Gilbert’s Annalen der Physik und Chemie, Vol. XXVIII for 1808; F. A. C. Gren’s Journal der Physik, Vol. I. for 1790; Humboldt, “Cosmos,” London, 1849, Vol. I. p. 344, and the reference to Gay-Lussac in Ann. de chimie et de physique, Vol. VIII. p. 167.

=A.D. 1790.=--Eandi (Giuseppe Antonio Francesco Geronimo), an able physicist, native of Saluces (1735–1799), reads, May 10, before the Academy of Sciences of Turin, a Memoir upon Electricity in vacuo which is printed in the Collections of that Institution. He studied for the priesthood and entered the Normal College of Turin, where he followed protracted courses of literature under Bartoli and of natural philosophy under Beccaria, becoming the assistant of the latter, whom he finally replaced from 1776 to 1781. He afterward became Professor of Natural Philosophy at the College of Fine Arts, where he gave particular attention to electrical studies, and published several papers on that science, as well as upon natural philosophy generally.

He bequeathed all his possessions to his nephew Vassalli, upon condition of the latter’s taking the name of Eandi.

Besides the above, he wrote: “Memorie istorische,” etc., or “Historical Memoir upon the Studies of Father Beccaria,” Turin, 1783, which is dedicated to Count Balbi and gives the new theories of electricity, also an “Essay upon the Errors of Several Physicists in Regard to Electricity,” Turin, 1788.

REFERENCES.--“Notice sur la vie ... d’ Eandi par Vassalli-Eandi,” Turin, 1804; “Biographie Générale,” Vol. XV. p. 589; Larousse, “Dict. Universel,” Vol. VII. p. 5; the Turin Academy Memoirs for the years 1802–1804; Eandi e Vassalli-Eandi, “Physicæ Experimentalis,” etc., Turin, 1793–1794.

=A.D. 1790.=--Vassalli-Eandi (Antonio Maria), Italian savant (1761–1825), nephew of G. A. F. G. Eandi, who was, like his uncle, a pupil of Beccaria, publishes his views concerning the electricity of bodies and regarding other investigations, as well as a report upon experiments relative to the electricity of water and of ice, which appear respectively in L. V. Brugnatelli’s Annali di Chimica, Vol. I. p. 53, in the “Bibl. Fis. d’Europa,” Vol. XVII. p. 144, and in the third volume of “Mem. della Soc. Italiana.”

He was one of the most prolific of Italian writers, his more important essays, which number 160, being written in Italian, Latin and French, and covering almost every leading branch of physical science. One of his biographers tells us, Il a embrassé, pour ainsi dire, l’ensemble des connaissances humaines, and that he is one of whom his country may justly be proud.

In his investigations concerning aerolites, which appeared in 1786 (“Memoria ... sopra ... bolidi in generale”), he explains the movements of those bodies much more satisfactorily than had previously been done by any scientist. Essays published by him during the same year, as well as in 1789 and 1791, treat of the effect of electricity upon vegetables; then follow his papers relative to Bertholon’s “Electricité des Météores,” to Haüy’s theories and to the meteorological observations of Senebier, De Saussure, Toaldo and Monge, up to 1792, when Vassalli was made Professor of Natural Philosophy at the Turin University. He had also in the meantime carefully looked into the scientific knowledge possessed by the ancients, and was led to believe, as shown in his “Conghietture sopra l’arte,” etc., that they had the means of attracting and directing thunder and lightning. The latter fact has been alluded to in this “Bibliographical History,” under the B.C. 600 entry. (See J. Bouillet, “De l’état des connaissances,” etc., Saint Etienne, 1862.)

He was after this made perpetual secretary of the Royal Academy of Sciences of Turin, then became Director of the Museum of Natural History, as well as of the Observatory situated in the last-named city, which position he held at the time of his death.

His other essays treat more particularly of animal electricity, the electricity of fishes, the effects of electricity upon recently decapitated bodies, the application of electricity and of galvanism to medicine, and cover very extended observations on meteorology. He was the editor of both the “Memoirs of the Academy of Sciences of Turin, from 1792 to 1809,” and of the “Annals of the Turin Observatory, from 1809 to 1818” (Larousse, “Dictionnaire Universel,” Vol. XV. p. 801); was likewise editor of the “Bibliothèque Italienne,” in conjunction with Giulio Gioberti and Francesco Rossi, and is said to have devised an electrometer superior to that of Volta.

REFERENCES.--Vassalli-Eandi, Giulio (or Julio) e Rossi, “Rapport présenté,” etc., Turin, 1802, or “Transunto del Rapporto,” etc., Milano, 1803 (“Opusc. Scelti,” Vol. XXII. p. 51), translated into English, London, 1803 (Phil. Mag., Vol. XV. p. 38); also Vassalli-Eandi, F. Rossi et V. Michelotti, “Précis de nouvelles expériences galvaniques,” Turin, 1809 (“Mém. de Turin,” Années, 1805–1808, p. 160). See likewise, S. Berrutti, “Elogio,” etc., 1839; “Saggio sulla vita ... Vassalli-Eandi,” Torino, 1825; “Notizie biografiche ... Vassalli Eandi” (“Mem. di Torino,” Vol. XXX. p. 19); “Elogio, scritto dal Berrutti” (“Mem. of the Ital. Soc.,” Vol. XXII. p. liv); Phil. Mag., Vol. XV. p. 319; Journal de Physique, An. VII. p. 336 and Vols. XLIX, L; “Ital. Soc. Mem.,” Vols. VIII. p. 516; X. p. 802; XIII. p. 85; XVII. p. 230; XIX. p. 347; “Mémoires de Turin,” Vols. X-XIII; “Mem. dell’ Acad. di Torino,” Vols. VI, X, XXII, XXIV, XXVI, XXVII, XXIX; “Mem. della Soc. Agrar. di Torino,” Vol. I; “Opuscoli Scelti,” Vols. XIX. pp. 215, etc.; XXII. p. 76; “Nuova Scelta d’Opuscoli,” Vol. I. p. 167; “Opuscoli Scelti di Milano,” quarto, Vol. XIV; “Mem. Soc. Ital.,” Vols. IV. p. 263; X. p. 733; “Biblioteca Oltramontana”; Brugnatelli’s Annali di Chimica; “Giornale Scientifico ... di Torino,” Vols. I, III; “Giornale Fis. Med.,” Vol. II. p. 110; “Biblioteca Italiana”--“Bibliothèque Italienne,” Vols. I. p. 128; II. p. 25; “Recueil périodique ... de Sédillot,” Vol. II. p. 266.

=A.D. 1790–1800.=--Morozzo--Morotius--(Carlo Luigi, Comte de), Italian savant, who studied mathematics under Lagrange, and was President of the Turin Academy of Sciences, publishes numerous scientific memoirs in French through the reports of the last-named institution, in one of which he is said to have described an experiment suggesting the electro-magnet.

REFERENCES.--Biography in Larousse, “Dictionnaire Universel,” Tome XI. p. 577, and in the “Biographie Générale,” Tome XXXVI. p. 643.

=A.D. 1791.=--Leslie (Sir John), an able English scientist (April 1766–Nov. 1832), who, upon the death of Prof. John Playfair, was called to the Chair of Natural Philosophy in the University of Edinburgh, writes a very interesting paper entitled “Observations on Electric Theories,” which is read the following year at the meeting of the Royal Society of Edinburgh, and is published at the latter place during 1824.

According to Carnevale Antonio Arella, “Storia dell’ Elettricità,” Alessandria, 1839, Vol. I. p. 130, Sir John Leslie is the author of quite an interesting treatise on the inefficacy of lightning conductors, and the “English Cyclopædia” (Biography), Vol. III. p. 866, gives a list of many of the numerous contributions he made to the leading publications of his day, more particularly in the “Edinburgh Philos. Transactions,” the “Encyclopædia Britannica,” the “Edinburgh Review,” and “Nicholson’s Philos. Journal.” The reviewer adds, what will surprise many readers, that, although some papers by Sir John Leslie treating of physical subjects were also read before the Royal Society of London, none were ever printed in their “Philos. Transactions.”

Professor John Playfair above alluded to (1748–1819), became, during 1785, Joint Professor of Mathematics with Dr. Adam Ferguson in the University of Edinburgh and, in 1805, exchanged this for the Professorship of Natural Philosophy in the same university.

REFERENCES.--Macvey Napier, “Memoir of Sir John Leslie,” 1838, which appeared in seventh edition of “Encycl. Britan.,” Vol. XIII; “Engl. Cycl.” (Biography); Rose, “New Gen. Biogr.”; Hœfer, “Nouv. Biogr. Gen.,” Paris, 1862, Vol. XXX. pp. 949–952 (giving full account of his works); “Encycl. Britan.,” ninth edition, Edinburgh, 1882, Vol. XIV. pp. 476–477; Sidney Lee, “Dict. Nat. Biogr.,” Vol. XXXIII. pp. 105–107 and Vol. XLVIII. pp. 413–414; Pierre Larousse, “Grand Dict. Univ.,” Vol. X. pp. 406–407; “Caledonian Mercury,” article of Prof. Napier summarized in the “Gentleman’s Magazine” for 1833, Vol. I. pp. 85–86. Consult also A.D. 1751 at Adanson; “Dove,” p. 256; Philosophical Magazine, Vols. XL and XLII.

=A.D. 1791.=--At p. 353, Chap. III of the first volume of Gmelin’s “Handbook of Chemistry,” it is stated that during 1791 James Keir (Kier) first showed, by immersing iron in a solution of nitrate of silver or fuming nitric acid, that many metals can be made to pass from their ordinary active state into a passive or electro-negative state and lose either wholly or in part their tendency to decompose acids and metallic oxides.

At pp. 167–170, Sixth Memoir, of Wm. Sturgeon’s “Scientific Researches” (Bury, 1850), treating of the application of electro-chemistry to the dissolution of simple metals in fluids, reference is made to the long line of investigations carried on by both Bergman and Keir, the last named having demonstrated that iron “acquires that altered state by the action of nitric acid which Sir John Herschel met with in his experiments, and has called prepared state, and that Schönbein and others call the peculiar or the inactive state” (Noad’s “Manual of Electricity,” London, 1859, p. 534). The iron which is active in nitric acid was called by Keir “fresh iron,” while that which became inactive he designated as “altered iron” (Sturgeon’s “Annals of Electricity,” Vol. V. p. 439).

Some remarkable phenomena in the display of which but one individual piece of metal is used, as first shown by Keir, remain, Sturgeon says, “without even an attempt at explanation by any of the philosophers under whose notice they have appeared.” Sir John Herschel pronounces them as of an “extraordinary character”; Prof. Andrews, after giving some very satisfactory explanations of several phenomena, acknowledges that he “can offer no explanation of most of the particular facts which have been described,” and Professor Schönbein “has not made public any conclusive explanation of them whatever” (Phil. Mag. for October 1837, p. 333, and for April 1838, p. 311).

This same James Keir, called by Watt “a mighty chemist” (1735–1820), has strangely by some been confounded with Robert Kerr, also a Scotchman, who was an able scientific writer and lived at about the same period (1755–1813). Kerr made valuable translations from Lavoisier and Linnæus which, during 1805, won for him a fellowship in the Edinburgh Royal Society. (Consult Sidney Lee, “Dict. of Nat. Biogr.,” London, 1892, Vol. XXI. p. 64, also the references therein given; and the article “Faraday” in the “Encycl. Britan.,” ninth edition, Edinburgh, 1879, Vol. IX. p. 30.)

REFERENCES.--Mrs. Amelia Moillet, “Sketch of the Life of James Keir,” 1859; Sidney Lee, “Dict. of Nat. Biog.,” London, 1892, Vol. XXX. pp. 313–314; Annales de Chimie for October 1837; Phil. Trans. for 1790, p. 353, as well as Hutton’s abridgment of the same, Vol. XVI. p. 694; Sturgeon’s “Annals of Electricity,” Vol. V. p. 427; Gmelin’s Chemistry, pp. 367, 370.

=A.D. 1791.=--Shaw (George), English naturalist, who became a Fellow of the Royal Society during the year 1789, communicates to the latter body a paper on the Scolopendra electrica and Scolopendra subterranea (“Linn. Soc. Trans.” I. pp. 103–111). This was afterward translated into Italian and appeared in Vol. IX. p. 26, of Brugnatelli’s Annali di Chimica. Mr. James Wilson, F.R.S.E., in his “Encycl. Brit.” article on Myriapoda, alludes to the Scolopendra electrica as figured by Frisch and described by Geoffroy in his “Histoire des Insectes,” Vol. II. p. 676, n. 5. Shaw also treats of the Trichiurus Indicus, which Sir David Brewster believes to be the same as the trichiurus electricus, known to inhabit the Indian Seas and to have the power of giving electric shocks.

Five years before the above date (1786), the Phil. Trans. contained (p. 382) the description of the tetraodon electricus, which Lieutenant William Paterson discovered in the cavities of the coral rocks of one of the Canary Islands and which he found to possess the properties of other electrical fishes. (See Hutton’s abridgments, Vol. XVI. p. 134.)

REFERENCES.--“Biographie Générale,” Vol. XLIII. p. 922; “Gentleman’s Magazine,” Vol. LXXXIII; Poggendorff, Vol. II. p. 918; “Cat. Royal Society Sc. Papers,” Vol. V. p. 674; Dr. Thomas Young, “Course of Lectures,” London, 1807, Vol. II. p. 436, for the Trichiurus Indicus....

Having thus far called attention to the most important varieties of the electrical fishes, notably at the articles Adanson (A.D. 1751), Bancroft (A.D. 1769), Walsh, also Hunter (A.D. 1773), the following original list of additional references will prove interesting:

Raia Torpedo.--Stephani Lorenzini, “Osservazioni ...” Firenze, 1678; R. A. F. de Réaumur, “Des Effets ...” Paris, 1714; Templeman, in “Nouvelliste,” 1759; Ingen-housz (Phil. Trans., 1775); Cavendish (Phil. Trans., 1776, Vol. LXI. p. 584, Vol. LXVI. p. 196, also Hutton’s abridgments, Vol. II. p. 485; Vol. XIII. p. 223; Vol. XIV. p. 23); F. Soave (“Scelta di Opuscoli,” Vol. XV), Milano, 1776; J. A. Garn, “De Torpedine ...” Witteb., 1778; R. M. de Termeyer (Raccolta Ferr. di Op. Sc. ... Vol. VIII), Venice, 1781; L. Spallanzani (“Goth. Mag.,” V. i. 41; “Opusc. Scelti,” VI. 73), Milano, 1783; Girardi and Walter (“Mem. Soc. Ital.,” III. 553), Verona, 1786; W. Bryant (“Tr. Amer. Phil. Soc.,” II. 166, O. S.), Philad., 1786; J. W. Linck, “De Raja Torpedine,” Lips., 1788; Vassalli-Eandi (_Journal de Physique_, Vol. XLIX. p. 69); Geoffroy Saint-Hilaire (“Annal. du Mus.,” An. XI. Vol. I., No. 5, and Phil. Mag., Vol. XV. p. 126), 1803; J. F. M. Olfers, “Die Gattung Torpedo ...” Berlin, 1831; Linari-Santi in “Bibl. Univ.,” Ser. II., Geneva, 1837–1838, and in “Bibl. Ital.,” Vol. XCII. p. 258, Milan, 1839; C. Matteucci, “Recherches ...” Genève, 1837 (“Royal Soc. Catalogue of Sc. Papers,” Vol. IV. pp. 285–293); also Delle Chiaje, “On the Organs ...” and P. Savi, “Etudes ...” Paris, 1844; G. Pianciani (“Mem. Soc. Ital.,” XXII. 7); F. Zantedeschi (“Bull. Acad. Brux.,” VIII. 1841); A. Fusinieri (“Ann. del Reg. Lomb.-Veneto,” VIII. 239), Padova, 1838; A. F. J. C. Mayer, “Spicilegium ...” Bonnæ, 1843; L. Calamai, “Osservazioni ...” 1845; C. Robin, “Recherches ...” Paris, 1847; Krünitz, “Abhandl.,” XVII; Nicholson’s Journal, Vol. I. p. 355; Rozier, IV. p. 205; “Acad. Brux.,” 111; “Phil. Hist. and Mem. of the Roy. Acad. of Sc. Paris,” 1742, Vol. V. pp. 58–73; John Ewing, at A.D. 1795; Dr. Godef. Will. Schilling (in original Latin, also the French translation), “Biblioth. Britannique,” Vol. XL. pp. 263–272; Dr. Jan Ingen-housz in Phil. Tr. Vol. LXV. p. 1; Vol. LXVIII. pp. 1022, 1027; Vol. LXIX. pp. 537, 661; also Hutton’s abridgments, Vol. XIII. p. 575; Vol. XIV. pp. 462, 463, 589, 598; “Journal des Sçavans,” Vol. LXXVIII. for January-April, 1726, p. 58; “The System of Natural History, written by M. De Buffon,” Edinburgh, 1800, Vol. II. pp. 24–25.

M. R. A. F. De Réaumur, mentioned above, has communicated the results of his investigations relative to the torpedo in “Mém. de Paris” for 1714, following it up more particularly with another article in the issue for year 1723 on magnetization, which is also alluded to in “Journal des Sçavans,” Vol. LXXXII. for 1727, p. 4.

Silurus Electricus.--Ranzi, on the discovery of the discharge of this animal; P. Forskal “Beobachtungen ...” 1775; F. Pacini, “Sopra l’ Organo ...” Bologna, 1846; Abd-Allatif, Relation de l’Egypte, p. 167, quoted at p. 250; Note XI. vol. i. of Libri’s “Hist. des Mathém.”; C. Maspero, “The Dawn of Civilization,” New York, 1894, p. 36, wherein it is said that the silurus was the nârû of the ancient Egyptians, as described by Isidore Geoffroy de St. Hilaire in his “Histoire Naturelle des Poissons du Nil.”

Gymnotus Electricus.--T. Richer, “Observations ...” Paris, 1679 (“Hist. et Mém. de l’Acad. Roy. des Sciences,” Vols. I. p. 116; VII. i. pt. 2, p. 92); “Edinburgh Review,” Vol. XVI. pp. 249–250; John Ewing at A.D. 1795; P. Sue, aîné “Histoire du Galvanisme,” Paris, An. X, 1802, Vol. II. pp. 94–97; A. Van Berkel, “Reise nach Rio ...” Memming, 1789, for the observations made in 1680–1689; J. B. Duhamel (“Hist. Acad. Sc.,” 168); J. N. Allamand, “On the Surinam Eel ... by S’Gravesande,” Haarlem, 1757; Gronov-Gronovius (“Acta Helvetica ...” IV. 26, Basle, 1760; Phil. Trans., Vol. LXV. part i. p. 94, 102, and part ii. p. 395); P. V. Musschenbroek (“Hist. et Méms. de l’Acad. des Sc.,” 1760); G. W. Schilling, “Diatribe de Morbo ...” 1770, treating of the torpedo as well as of the magnetism of the Gymnotus (which latter was observed by him in 1764, and is alluded to besides by Jan Ingen-housz in his “Nouv. Exper.,” Paris, 1785); “Mem. of Berlin Acad. of Sc.,” Bonnefoy, “De l’app. de l’élect ...” 1782–1783, p. 48; Ferdinando Elice, “Saggio sull’ Elettricità,” p. 26; H. Williamson, Alexander Garden and John Hunter in the Phil. Trans. for 1775, p. 94, 102, 105, 395, and in Hutton’s abridgments, Vol. XIII. pp. 597–600; R. M. de Termeyer (“Opus. Scelti,” IV. 324, for 1781); H. C. Flagg (“Trans. Amer. Phil. Soc.,” O. S., Vol. II. p. 170); Samuel Fahlberg, “Beskrifning ofver elektriska alen Gymnotus electricus,” Stockholm, 1801; (See Fahlberg at A.D. 1769, and in “Vet Acad. Nyr. Handl.”; Gilbert, Annalen, XIV. p. 416); Humboldt, “Observations ... anguille elect ...” Paris, 1806; “Versuche ... elec. fische,” Jena, 1806; also in the Annales de Chimie et de Physique, Vol. XI for 1819, and at p. 256 of the “Harmonies of Nature,” by Dr. G. Hartwig, London, 1866, will be found a picture showing mode of capture of the Electric Eel; F. S. Guisan, “De Gymnoto ...” Tübingen, 1819, Carl Palmstedt (“Skand. Naturf. motets Forhand,” 1842); H. Letheby (“Proceedings London El. Soc.,” Aug. 16, 1842, and June 17, 1843); M. Vanderlot’s work, alluded to by Humboldt at p. 88 of his “Voyage ...”; F. Steindachner, “Die Gymnotidie ...” Wien, 1868.

Consult likewise, for reputed magnetic powers of the echeneis, or sucking-fish, Gaudentius Merula, “Memorabilium,” 1556, p. 209; Fracastorio, “De Sympathia,” lib. 1, cap. 8; W. Charleton, “Physiologia,” 1654, p. 375; Cornelius Gemma, “De Naturæ Divinis,” 1575, lib. 1, cap. 7, p. 123; and, for electrical fishes generally, Rozier, Intr., II. p. 432; Bloch, “Naturgeschichte ...” Berlin, 1786; A. De la Rive, “Traité de l’électricité,” Paris, 1858, Vol. III. pp. 61–82; Rozier, Vol. XXVII. pp. 139–143; “Works of Michael de Montaigne,” by W. Hazlitt, New York, 1872, Vol. II. pp. 158–159; R. J. Haüy, “Traité de Physique,” p. 41; Geoffroy Saint-Hilare (Journal de Physique, LVI. 242; Phil. Mag. XV. 126–136, 261; “B. Soc. Phil.” N. 70; Gilbert, Annalen, XIV. 397; “Ann. du Mus.” for 1803); M. Schultze, “Zur Kentniss ... elect ... fische,” Halle, 1858 and 1859; Jobert (de Lamballe) “Des Appareils ...” Paris, 1858; W. Keferstein and D. Kupffer (Henle u. Pfeuffer’s “Zeitschr. f. rat. Med. Newe Folgc,” III. 1858) and Keferstein’s “Beitrag ... elekt. fische,” Göttingen, 1859; “Annual of Sc. Discovery” for 1863, giving, at pp. 115–116, the views of Sir John Herschel, of Charles Robin and of M. Moreau on the electrical organs of fishes.

=A.D. 1792.=--Berlinghieri (Francesco Vacca, and not Vacca Leopold nor Andrea Vacca), Italian surgeon and anatomical writer, communicates to M. De La Méthérie the result of the extensive experiments made by him in concert with M. Pignotti and his brother. After describing his investigations with frogs, he remarks that the same movements and contractions can be produced on animals with hot blood, but that the latter require a peculiar process. He says that after having dissected the crural or any other considerable nerve, and cut it at a certain height to separate it from its superior part, it should have a piece of tinfoil wrapped around its summit, and the communication should be made in the usual way by touching the coating with one of the extremities of the exciting arc and the muscles in which the nerve is distributed with the other extremity.

Many other investigations of Berlinghieri were, later on, communicated to the Société Philomathique, by whom they were successfully renewed, and, during the year 1810, a translation of his paper on the method of imparting magnetism to a bar of iron without a magnet appeared at p. 157, Vol. XXXV. of the Philosophical Magazine.

REFERENCES.--Rozier, XL. p. 133, and XLI. p. 314; “Giorn. di Med. Prac. di Brera,” IX. pp. 171–298; L. B. Phillips, “Dict. of Biog. Ref.,” 1871, p. 137; Tipaldo, “Biografia ...” 1834.

=A.D. 1792.=--Lalande (Joseph Jérome le Français de), a distinguished scientist, and, doubtless, the best known of all French astronomers, who had previously communicated (1761) observations on the loadstone to the “Mémoires de Paris,” and had likewise written upon meteoric displays (1771), addresses to the Journal des Sçavans of Nov. 1792 a treatise entitled “Une Notice sur la découverte du Galvanisme,” justifying his claim to being the first introducer of galvanism into France, which he had before made through the columns of the Journal de Paris of the 17 Pluviôse, An. VII.

REFERENCES.--Lalande, “Abrégé de l’Astronomie,” pp. 101, etc.; “Biog. Générale,” Vol. XXVIII. p. 948; “Biog. Universelle,” Vol. XXII. pp. 603–613; Ninth “Enc. Britannica,” Vol. XIV. p. 225; P. Sue, aîné, “Hist. du Galv.,” Paris, An. X (1802), Vol. I. p. 1.

=A.D. 1792.=--Chappe (Claude), a French mechanician (1763–1805), introduces the sémaphore, which he at first called a tachygraphe, from two Greek words meaning to write fast, but to which M. Miot, chief of one of the divisions of the War Department, gave the name of telegraph during the year 1793. Chappe had not long before devised a contrivance somewhat like that alluded to by Barthélémy (A.D. 1788), but it was not apparently brought into use.

His sémaphore consisted of a vertical wooden pillar 15 feet or 16 feet high, bearing a transverse beam 11 feet or 12 feet long, which turned upon its centre and held at each extremity pivoted arms so worked by cords or levers as to admit of 256 distinct signals. The semaphores were placed upon high towers, about four miles apart, on level ground, and even as much as ten miles apart upon intervening elevations. This system of signals was presented by Chappe to the Assemblée Législative, and was originally erected during the month of August 1794 upon stations between Paris and Lille (Lisle), a distance of about 148 miles. One of the first sentences conveyed between the two places by the Committee of Public Safety consumed 13 minutes and 40 seconds, but it was not long before dispatches could be conveyed in two minutes’ time, and it was through Chappe’s apparatus that the news of the recapture of the city of Condé was conveyed to the Assembly shortly after the entry of the troops of the Republic.

It is not now believed that Claude Chappe was acquainted with the devices of either Robert Hooke (at A.D. 1684) or of Guillaume Amontons (at A.D. 1704), as was at the time claimed by many of his jealous contemporaries. No doubt exists that he is justly entitled to the credit of having, with the assistance of other members of his family, developed an entirely new system of signals as well as the mechanism by which they were operated. The histories of telegraphy written by I. U. J. Chappe (Paris, 1824; Le Mans, 1840) review Claude Chappe’s investigations and the difficulties he encountered, besides making reference to the false magnetic telegraphs of A. T. Paracelsus (A.D. 1490–1541), William Maxwell (A.D. 1679), and F. Santanelli (“Philosophiæ reconditæ ...” Coloniæ, 1723) alluded to in the “Dictionnaire des Sciences Médicales.”

Claude Chappe’s uncle, L’Abbé Jean Chappe d’Auteroche (1722–1769), French astronomer, who succeeded N. L. de la Caille at the Paris Observatory as assistant to Cassini de Thury and edited a translation of the works of Dr. Halley, is the author of several memoirs upon the declination and inclination and upon lightning, meteors, etc., alluded to in J. B. J. Delambre’s “Hist. de l’Astron. au 18^e siècle,” in J. C. Poggendorff’s “Biog.-Liter. Hand.,” Vol. I. p. 420, and in the “Mém. de Paris,” 1767, Mém. p. 344.

REFERENCES.--English Encycl., “Arts and Sciences,” Vol. VIII. p. 65; “Johnson’s Encycl.,” Vol. IV. p. 757; “Penny Ency.,” Vol. XXIV. p. 146; Shaffner, “Manual,” pp. 27, 45 and 48; “Le Cosmos,” Paris, Feb. 4, 1905, p. 128; Nicholson’s “Journ. of Nat. Phil.,” Vol. VIII. p. 164, note; Sc. American Supplement, No. 475, p. 7579; “Emporium of Arts and Sciences,” Vol. I. p. 292; Rozier, XXXIV. p. 370, and XL. p. 329; “Bull. des Sc. de la Société Philomathique,” March 1793, No. 21, for an account of the experiments of Galvani and of Valli repeated for the Society by C. Chappe, M. Robillard and A. F. de Silvestre.

=A.D. 1792.=--Valli (Eusebius), Italian physician of Pisa, corresponding member of the Royal Academy of Sciences at Turin, publishes his “Experiments on Animal Electricity” the results of which were communicated to the French Academy of Sciences and found to be of such great importance that a committee composed of Messrs. Le Roy, Vicq d’Azyr, Coulomb and Fourcroy, was directed to repeat them. The most important were repeated in Fourcroy’s laboratory on the 12th of July 1792.

Valli was the first to demonstrate that when an arc of two metals, plumber’s lead and silver, is employed upon an animal, the most violent contractions are produced while the lead is applied to the nerves and the silver to the muscles. He also showed that of all metals, zinc, when applied to the nerves, has the most remarkable power of exciting contractions; and he found that when a frog had lost its sensibility to the passage of a current, it regained it by repose.

These experiments were also repeated before the French Royal Society of Medicine. M. Mauduyt, who was present, deduced from the results obtained by Valli that the metals were charged with a different quantity of the electric fluid, in so much that when they were brought in contact with each other a discharge ensued. And, secondly, that the animal body, by which the electric fluid is rendered perceptible, is a more delicate electrometer than any one heretofore discovered.

Many new and very interesting investigations were afterward made by Valli upon different animals, the results of which were given to the public through the columns of the Journal de Physique as shown below. These embrace thirteen experiments upon animals rendered insensible by means of opium and powdered tobacco, showing electricity to be independent of their vitality, as well as others to show that the electric fluid is necessary to man and animals. He fully established the identity of the nervous and the electric fluids, and proved that the convulsions took place by merely bringing the muscles themselves into contact with the nerves, without the intervention of any metal whatever. In answer to the inquiry of M. Vicq d’Azyr, member of the late French Academy of Sciences, he supported by nineteen experiments the assertion that however the blood vessels may be, as they assuredly are, conductors of electricity, the nerves alone prove capable of exciting muscular movements in consequence of the mode in which they are disposed.

REFERENCES.--Brugnatelli, Annali di Chimica, Vol. VII. pp. 40, 213, 228 (and pp. 138, 159, 186, 208 for Caldani); also the “Giornale Fis. Med. di Brugnatelli,” Vol. I. p. 264; Sue, “Histoire du Galvanisme,” Paris, An. X-1802, Vol. I. p. 45; “Société Philomathique,” Vol. I. pp. 27, 31, 43; Journal de Physique, Vol. XLI. pp. 66, 72, 185, 189, 193, 197, 200, 435; Vol. XLII. pp. 74, 238, the last named containing the “Lettre sur l’Electricité Animale” (“De animalis electricæ theoriæ ...” Mutinæ, 1792) sent by Valli to MM. De La Méthérie and Desgenettes; Report of MM. Chappe, Robillard and Silvestre on Valli’s and Galvani’s experiments (“Soc. Phil.” for March 1793, No. 21); Report of Messrs. Le Roy, Vicq d’Azyr and Coulomb in “Médecine éclairée par les Sciences Physiques,” Tome IV. p. 66; “Epitome of Electricity and Magnetism,” Philad., 1809, p. 133; “Versuche ... animal, electricität” of Karl Friedrich Kielmayer (Kielmaier) of the Tübingen University (Poggendorff, Vol. I. p. 1253; F. A. C. Gren, Journal der Physik, Vol. VIII for 1794); Floriano Caldani’s works, 1792–1795, and those of Leopoldo Marc-Antonio Caldani, 1757–1823; Junoblowiskiana Society, 1793–1795.

=A.D. 1793.=--Fontana (Felice), distinguished Italian experimental philosopher and physiologist, gives in his “Lettere sopra l’ Elettricità Animale,” the result of further extensive investigations carried on by him to ascertain more especially all the features of galvanic irritability and the peculiar actions of the several organs in cases of death by electricity. Some of his previous observations in the same line had already been made known through his “Di Moti dell’ Iride,” 1765, and “Richerche filosofiche,” 1775, all which led to an active correspondence in after years with the Italian Giochino Carradori, as will be seen by consulting the volumes of Luigi Valentino Brugnatelli’s well-known “Giomale Fisico-Medico” (Cuvier, in “Biog. Univ.,” Vol. XV. p. 8, par. 1816; “Giornale Fisico-Medico,” Vol. IV. p. 116).

Fontana (Gregorio), younger brother of Felice Fontana, likewise an able natural philosopher, succeeded the celebrated Ruggiero Giuseppe Boscovich in the Chair of Higher Mathematics at the University of Padua, and is the author of “Disquisitiones physico-mathematicæ,” Papiæ, 1780, as well as of many papers in the “Mem. della Soc. It. delle Scienze,” wherein he gives detailed accounts of many very interesting electrical observations. Mention of Gregorio Fontana’s name has already been made under Bennet, A.D. 1787.

REFERENCES.--Houzeau et Lancaster, “Bibl. Gén.,” Vol. I. part i. p. 334, and, for R. G. Boscovich, “The Edinburgh Encyclopædia,” 1830, Vol. III. pp. 744–749.

=A.D. 1793.=--Aldini (Giovanni), nephew of Luigi Galvani and one of the most active members of the National Institute of Italy, who succeeded his former instructor, M. Canterzani, in the Chair of Physics at the Bologna University, established in the last-named Institution a scientific society whose open object was to combat all of Volta’s works and which became very hostile to the organization already formed in the University of Pavia by Felice Fontana, Bassiano Carminati and Gioachino Carradori against the followers of Galvani. Similar societies espousing the cause of Volta were subsequently organized in England, at the suggestion of Cavallo and others, and during five years, the scientists of Europe were divided between the two discoverers, without, however, any material benefit accruing therefrom to either faction.

Aldini proved to be an indefatigable investigator, as shown by the numerous Memoirs sent by him to the publications named below, up to the month of October 1802, when he experimented before the Galvani Society of Paris. An account of these experiments is given in his “Essai théorique,” etc., where, among other results, attention is called to the curious fact that contractions can be excited in a prepared frog by holding it in the hand and plunging its nerves into the interior of a wound made in the muscle of a living animal (Figuier, “Exposition,” etc., Vol. IV. p. 308). His interesting investigations of the artificial piles of muscle and brain, first made by M. La Grave and shown to the French Galvani Society, are alluded to in Nicholson’s Journal, Vol. X. p. 30, in the Journal de Physique, An. XI. pp. 140, 159, 233, 472, and in Sturgeon’s “Scientific Researches,” Bury, 1850, p. 195.

Nearly all of Aldini’s experiments were successfully repeated in London at Mr. Wilson’s Anatomical Theatre, where Mr. Cuthbertson assisted Prof. Aldini in arranging the apparatus, and where a student, by the name of Hutchins, furnished the anatomical preparations, but the demonstration, of all others, which attracted most attention was doubtless the one made in London on the 17th of January 1803. The murderer Forster had just been executed and, after his body lay for one hour exposed in the cold at Newgate, it was handed over to Mr. Koate, President of the London College of Surgeons, who, with Aldini, made upon it numerous important observations to ascertain the precise effects of galvanism with a voltaic column of one hundred and twenty copper and zinc couples. The extraordinary results obtained, which cannot properly be enumerated here, are to be found in the “Essai Théorique,” etc., already alluded to. They led Aldini to believe he could, by the galvanic agency, bring back those in whom life was not totally extinct, such as in cases of the recently drowned or asphyxiated. (Consult M. Bonnejoy’s method of proving death by ... Faradization, Paris, 1866, and Georgio Anselmo, “Effets du Galvanisme ...” Turin, 1803; S. T. Sömmering, “On the application of Galvanism to ascertain the reality of death,” Ludwig scripter nevrolog., III. 23; Ure, “Exper. on the body of a criminal ...” “Journal of Sc. and Arts,” No. XII; Phil. Mag., Vol. LIII. p. 56; Jean Janin de Combe Blanche, “Sur les causes,” etc., Paris, 1773 (hanging); C. W. Hufeland, 1783, for the app. of Elec. in cases of asphyxia; T. Kerner, for the app. of Galv. and Magn. as restoratives, Cannstadt, 1858; Wm. Henley, for electricity as a stimulant ... drowned or ... suffocated, “Trans. of the Humane Society,” Vol. I. p. 63.)

Another of Aldini’s curious experiments was the production of very powerful muscular contractions upon the heads of oxen and other animals recently decapitated, by introducing into one of the ears a wire connecting with one of the battery poles and into the nostrils or tongue a wire communicating with the other pole. Thus were the eyes made repeatedly to open and roll in their orbits while the ears would shake, the tongue move and the nostrils dilate very perceptibly (De la Rive, “A Treatise on Electricity,” 1856, Vol. II. p. 489, and 1858, Vol. III. p. 588; Pepper, “Voltaic Electricity,” 1869, pp. 287, 288). In the experiments which Aldini made during 1804 upon corpses, the body became violently agitated and even raised itself as if about to walk, the arms alternately rose and fell and the forearm was made to hold a weight of several pounds, while the fists clenched and beat violently the table upon which the body lay. Natural respiration was also artificially re-established and, through pressure exerted against the ribs, a lighted candle placed before the mouth was several times extinguished.

For the experiments of the eminent French physiologist and anatomist Marie François Xavier Bichat, of Vassalli-Eandi, Giulio, Rossi, Nysten, Hallé, Mezzini, Klein, Bonnet, Pajot-Laforest, Dudoyon, Berlinghieri, Fontana, Petit-Radel, Alizeau, Lamartillière, Guillotin, Nauche and others upon animals and men recently decapitated, see Bichat’s “Recherches Physiologiques sur la vie et la mort,” Paris, 1805; Francesco Rossi’s “Rapport des expériences,” etc., Turin, 1803; P. H. Nysten’s “Nouvelles Expériences Galvaniques,” etc., Paris, 1811, and also the latter’s “Expériences faites ... le 14 Brumaire, An. XI.” (Consult likewise, J. R. P. Bardenot, “Les Recherches ... refutées,” Paris, 1824, and, for an account of Bichat consult F. R. Buisson, “Précis historique ...” Paris, 1802; Larousse, Vol. II. pp. 703, 704; “Biog. Univ.,” Vol. XI. pp. 2–19.)

In Aldini’s “Account of Galvanism,” printed for Cuthell and Martin, London, 1803, it is said (p. 218) that, on the 27th of February 1803, he transmitted current through a battery of eighty silver and zinc plates from the West Mole of Calais harbour to Fort Rouge, by means of a wire supported on the masts of boats, and made it return through two hundred feet of intervening water.

REFERENCES.--J. B. Van Mons’ treatise on animal electricity in Tome III of the sixth year of the “Magasin Encyclopédique”; Fowler, in “Bibl. Britannica,” May 1796; Giulio e Rossi (“Gior. Fis. Med. di Brugnatelli,” 1793, Vol. I. p. 82); P. Sue, ainé, “Hist. du Galvanisme,” Paris, An. X, 1802, Vol. I. pp. 31, 67, 73; Vol. II. p. 268; Brugnatelli, Annali di Chimica, Vols. XIII. p. 135; XIV. p. 174; XIX. pp. 29, 158; “Opuscoli Scelti,” Vols. XVII. p. 231; XIX. p. 217; XX. p. 73; XXI. p. 412; “Mem. Soc. Ital.,” Vol. XIV. p. 239; Poggendorff, Vol. I. p. 27; “Bibl. Britan.,” Vol. XXII. 1803, pp. 249–266; “Galvanische und elektrische ... Körpern,” 4to, Frankfort, 1804; “Bull. des Sc. de la Soc. Philom.,” No. 68; J. C. Carpue, “Bibl. Britannica,” Nos. 207, 208, p. 373; Phil. Mag., Vols. XIV. pp. 88, 191, 288, 364; XV. pp. 40, 93; Cassius Larcher, M. Daubancourt et M. Zanetti, ainé (Ann. de Chimie, Vol. XLV. p. 195); also Larcher, Daubancourt et M. de Saintiot (Précis succinct, etc., Paris, 1803); W. Sturgeon, “Scientific Researches,” Bury, 1850, p. 194; M. Kilian, “Versuche über restitution ...” Giessen, 1857; Gilbert, IV. 246; J. Tourdes (“Décade Philos.” No. 3, An. X. p. 118); Francesco Rossi (“Bibl. Ital.,” Vol. I. p. 106; Phil. Mag., Vol. XVIII. p. 131; and in the “Mémoires de Turin”); J. J. Sue, “Recherches Physiol.,” etc., 1803, p. 77; Vassalli-Eandi (“Expériences sur les décapités ...” Turin, 1802 and “Recueil ... de Sédillot,” Vol. II. p. 266); C. H. Wilkinson, “Elements of Galvanism,” etc., London, 1804, 2 Vols. passim; Report of MM. Chappe, Robillard and Silvestre (“Bull. des Sciences de la Soc. Philom.,” No. 21 for March 1793; also Jour. de Phys., Vol. XLII. p. 289); M. Payssé (“Jour. de la Soc. de Pharm.,” first year, p. 100); Dr. Crichton (“Rec. Périod. de Litt. Méd. Etrangère,” Tome II. p. 342); J. Louis Gauthier, “Dissertatio,” etc., Hales, 1793 (“Com. de Leipzig,” Tome XXXVI. p. 473); Gardiner’s “Observ. on the animal œconomy”; Humboldt (“Soc. Philom.,” Vol. I. p. 92); Alex. Monro’s “Experiments,” etc., Edin., 1793, 1794 (“Trans. Edin. Roy. Soc.,” Vol. III); Felice Fontana, “Lettere ...” 1793; Joseph Izarn, “Manuel du Galvanisme,” Paris, An. XII, 1804, pp. 97, 138, 141, 160, 163, 285; Louis Figuier, “Exposition et Histoire,” Vol. IV. pp. 307–308, 358, 360–363, 365, 366, 370, 371.

=A.D. 1793.=--Fowler (Richard), a very ingenious physician, of Salisbury, makes known in Edinburgh his “Experiments and Observations relative to the influence lately discovered by Galvani and commonly called Animal Electricity,” of which a very complete review is made by Dr. G. Gregory at pp. 374–381, Vol. I of his “Economy of Nature,” etc., third edition, published in London during the year 1804.

Dr. Fowler observed that the contractions in a frog are excited by making the metals touch under water even at the distance of an inch from the divided spine of the animal. He succeeded in causing the heart to contract, but could not produce the same effect upon the stomach and intestines. He also found, as did Prof. John Robison, of Edinburgh, at the same period, that the senses of touch and smell are unaffected by the metals, but that when these are applied to the eye, or, what is better, when they are thrust up between the teeth and the lips, and then made to touch, a flash of light is rendered visible. This is the case also when the metals are placed between the gums and the upper and lower lips, as proven by the experiments of Dr. Rutherford and of Mr. George Hunter, of York. Fowler likewise observed that all pure metals prove excellent conductors of the galvanic influence and that living vegetables afford it a ready passage, but that stones and oils seem to be possessed of no conducting power whatsoever.

In conjunction with Mr. Alexander Munro, Fowler published a work on animal electricity (translated into German under the title of “Abhandlung ueber thierische elekt.” etc.), while, in the “Bibliotheca Britannica” for May 1796, mention will be found of the observations of Dr. Fowler respecting the muscular irritability excited by electricity, as well as on the reproduction of the nervous substance, on the action of poisons, on the phenomena of muscular contraction, etc. etc.

REFERENCES.--“Essays and Observations,” etc., Edinburgh, 1793, in Library of the Royal Institution; Gilbert Blane’s paper read to the English Royal Society, of which an extract can be found in Bacher’s “Medical Journal,” Vol. XC. p. 127; Figuier, “Exp. et Hist. des Princip. Déc.,” Vol. IV. p. 309; C. H. Wilkinson, “Elements of Galvanism,” London, 1804, Chap. VI. et passim; eighth “Encyc. Brit.,” Vol. XXI. p. 634.

=A.D. 1793.=--Dalton (John), LL.D., F.R.S. (1766–1844), a very able English natural philosopher and the illustrious author of the “Atomic Theory of Chemistry and of the Constitution of Mixed Gases,” gives in his earliest separate publication, “Meteorological Observations and Essays,” the result of many experiments upon the electricity of the atmosphere, made by him at Kendal and at Keswick during the seven years ending May 1793.

He proved, as Sir David Brewster expresses it, that the aurora exercises an irregular action on the magnetic needle, that the luminous beams of the aurora borealis are parallel to the dipping needle; that the rainbow-like arches cross the magnetic meridian at right angles; that the broad arch of the horizontal light is bisected by the magnetic meridian; and that the boundary of a limited aurora is half the circumference of a great circle crossing the magnetic meridian at right angles, the beams perpendicular to the horizon being only those on the magnetic meridian.

In the eighth “Encyclopædia Britannica” (Vol. IV. p. 246), treating of the height of polar lights, reference is made to the extraordinary aurora borealis observed by Dalton on the 29th of March 1826, and of which a description is given in a paper read before the Royal Society, April 17, 1828 (Phil. Mag. or Annals, Vol. IV. p. 418; Philosophical Transactions for 1828, Part II; James Hoy in Phil. Mag., Vol. LI. p. 422; J. Farquharson in Phil. Trans. for 1839, p. 267). This aurora was seen in places one hundred and seventy miles apart and covered an area of 7000 to 8000 square miles. In Vol. XIV of the same Encyclopædia will be found (p. 15), an account of another aurora observed at Kendal, February 12, 1793, while at p. 12 are given Dalton’s views as to the connection between the heat and magnetism of the earth, and, at p. 66, his conclusions as to the cause of the aurora and its magnetic influence.

REFERENCES.--“Memoirs of Dalton’s Life,” by Dr. W. C. Henry, London, 1854; “Life and Discoveries of Dalton,” in _British Quarterly Review_, No. 1; Pharmaceutical Journal, London, October 1841; Thomson’s “History of Chemistry,” Vol. II; Young’s “Course of Lectures,” London, 1807, Vol. I. pp. 706–709, 753, and Vol. II. pp. 466–470; Noad, “Manual,” etc., London, 1859, pp. 226, 269, 534; article, “Aurora Borealis,” immediately following A.D. 1683; Sir H. Davy, “Bakerian Lectures,” London, 1840, pp. 322, 323, 328–330; “Dict. of Nat. Biog.,” Vol. XIII. pp. 428–434, as well as the numerous references therein cited. Consult also, for theories, investigations, observations, records, etc., of the Aurora Borealis: Georg. Kruger, 1700; J. J. Scheuchzer, 1710–1712, 1728–1730; L. Feuillée, 1719; J. L. Rost, 1721; J. C. Spidberg, 1724; W. Derham, 1728, 1729–1730; F. C. Mayer--Meyer, 1726; J. F. Weidler, 1729, 1730, 1735; J. Lulolfs, 1731; M. Kelsch, 1734; F. M. Zanotti, 1737, 1738; also Zanotti and P. Matteucci, 1739; B. Zendrini, J. Poleni, F. M. Serra, E. Sguario and D. Revillas in 1738; G. Bianchi, 1738 and 1740; J. M. Serantoni, 1740; G. C. Cilano de Maternus, 1743; S. von Trienwald, 1744; G. Guadagni, 1744; J. F. Ramus, 1745; C. Nocetus, 1747; P. Matteucci, 1747; Jno. Huxham, 1749–1750; G. W. Krafft, 1750; P. Kahm--Kalm, 1752; G. Reyger, 1756; A. Hellant, 1756, 1777; Jos. Stepling, 1761; H. Hamilton, 1767, 1777; M. A. Pictet, 1769; J. E. Silberschlag, 1770; C. E. Mirus, 1770; J. E. B. Wiedeburg, 1771; Max. Hell, 1776; Mr. Hall, J. H. Helmuth, 1777; E. H. de Ratte, W. L. Krafft, 1778; J. E. Helfenzrieder, 1778; G. S. Poli, 1778–1779; Marcorelle and Darguier, 1782; L. Cotte, 1783; J. A. Cramer, 1785; D. Galizi, in A. Calogera’s “Nuova Raccolta ...” Vol. XXXIX. p. 64; J. L. Boeckmann, in “Mem. de Berlin” for the year 1780; H. Ussher, 1788; G. Savioli, 1789, 1790; J. J. Hemmer, 1790; P. A. Bondoli, 1790, 1792, 1802; A. Prieto, 1794; J. D. Reuss’s works published in Göttingen; Jacopo Penada, 1807–1808; M. Le Prince, “Nouvelle Théorie ...”; W. Dobbie, 1820, 1823; Col. Gustavson, in Phil. Mag. for 1821, p. 312; M. Dutertre, 1822; J. L. Späth, 1822; Chr. Hansteen, 1827, 1855; L. F. Kaemtz, 1828, 1831; G. W. Muncke, 1828; J. Farquharson, 1829; D. Angelstrom, Rob. Hare, 1836; Ant. Colla, 1836, 1837; L. Pacinotti, 1837; G. F. Parrot, 1838; J. H. Lefroy, 1850, 1852; Don M. Rico-y-Sinobas, 1853; A. A. de La Rive, 1854; A. Boué (Katalog), 1856, 1857; C. J. H. E. Braun, 1858; E. Matzenauer, 1861; F. Dobelli, 1867; F. Denza, 1869.

=A.D. 1793–1797.=--Robison (John), a very distinguished English natural philosopher, completes what are without question the most important of all his scientific publications. These are to be found throughout the eighteen volumes and two supplements to the third “Encyclopædia Britannica,” where they cover such subjects as Physics, Electricity, Magnetism, Thunder, Variation, etc. etc. Taken together, “they exhibited,” according to Dr. Thomas Young, “a more complete view of the modern improvements of physical science than had previously been in the possession of the British public.”

It was after his retirement from the navy that Robison devoted himself to scientific studies, becoming the successor of Dr. Black in the lectureship of chemistry at the University of Glasgow during 1766, and accepting, seven years later (1773), the Professorship of Natural Philosophy at Edinburgh, where he taught all branches of physics and of the higher mathematics. In 1783 he was made Secretary of the Philosophical Society of Edinburgh, received the degree of Doctor of Laws, 1798–1799, and was elected foreign member of the Saint Petersburg Academy of Sciences in 1800. Of him, Mr. James Watt wrote, Feb. 7, 1805: “He was a man of the clearest head and the most science of anybody I have known” (Arago’s “Eloge of Jas. Watt,” London, 1839, p. 81).

It was while acting as midshipman under Admiral Saunders that Robison himself observed the effect of the aurora borealis on the compass, which had been remarked by Hiörter, Wargentin, and Mairan several years before, but which was not then generally known. The aurora borealis, he afterwards wrote, “is observed in Europe to disturb the needle exceedingly, sometimes drawing it several degrees from its position. It is always observed to increase its rate of deviation from the meridian; that is an aurora borealis makes the needle point more westerly. This disturbance sometimes amounts to six or seven degrees, and is generally observed to be greatest when the aurora borealis is most remarkable.... Van Swinden says he seldom or never failed to observe aurora borealis immediately after any anomalous motion of the needle, and concluded that there had been one at the time, though he could not see it.... This should farther incite us to observe the circumstance formerly mentioned, viz., that the South end of the dipping needle points to that part of the heavens where the rays of the aurora borealis appear to converge....”

The experiments of J. H. Lambert (at A.D. 1766–1776) upon the laws of magnetic action were carefully repeated by Robison, who, in 1769 or 1770, tried various methods and made numerous investigations from which he deduced that the force is inversely as the square of the distance. When he observed, however, some years afterward, that Æpinus had in 1777 conceived the force to vary inversely as the simple distance, he carefully again repeated the experiments and added others made with the same magnet and with the same needle placed at one side of the magnet instead of above it. By this simple arrangement the result was still more satisfactory, and the inverse law of the square of the distance was well established.

Throughout his numerous investigations, Prof. Robison found that when a good magnet was struck for three-quarters of an hour, and allowed in the meantime to ring, its efficacy was destroyed, although the same operation had little effect when the ringing was impeded; so that the continued exertion of the cohesive and repulsive powers appears to favour the transmission of the magnetic as well as of the electric fluid. The internal agitation, produced in bending a magnetic wire around a cylinder, also destroys its polarity, and, it is said, the operation on a file has the same effect. M. Cavallo found that brass becomes generally much more capable of being attracted when it has been hammered, even between two flints; and that this property is again diminished by fire: in this case, Dr. Thomas Young remarks, it may be conjectured that hammering increases the conducting power of the iron contained in the brass, and thus renders it more susceptible of magnetic action.

Of his other very important observations in the same line it would be difficult to select the most interesting, and it may suffice to call attention merely to such as are noted throughout Prof. Alfred M. Mayer’s valuable contributions on “The Magnet, Magnetism,” etc., in Johnson’s “New Universal Encyclopædia,” as well as in his “Practical Experiments in Magnetism,” etc., published through the columns of the Scientific American Supplement.

Prof. Robison’s electrical investigations are scarcely less interesting. In the theories advanced by Æpinus and Cavendish it was shown that the action of the electrical fluid diminished with the distance, while M. Coulomb proved, by a series of elaborate experiments, that it varied like gravity in the inverse ratio of the square of the distance. Robison had previously determined that in the mutual repulsion of two similarly electrified spheres the law was slightly in excess of the inverse duplicate ratio of the distance, while in the attraction of oppositely electrified spheres the deviation from that ratio was in defect; and he therefore arrived at the same conclusion formed by Lord Stanhope, that the law of electrical attraction is similar to that of gravity.

At the close of Richard Fowler’s “Experiments and Observations,” etc., Edinburgh, 1793, is a letter from Prof. Robison, wherein he gives the following results of many curious investigations, mostly made upon himself, to ascertain the effects of the galvanic influence. He found the latter influence well defined on applying one of two metallic substances to a wound which he had accidentally received; discovered by their tastes the solders in gold and silver trinkets; and showed that the galvanic sensation can be felt when the metallic substances are placed at a distance from each other. He proved the last-named fact by placing a piece of zinc between one of the cheeks and the gums, and a piece of silver on the opposite side within the other cheek. He next introduced a zinc rod between the piece of zinc and the cheek on the one side, and a silver rod between the silver and the cheek on the other, and when he afterward carefully brought into contact the extremities of the rods outside the mouth a flash appeared and a powerful sensation was noticeable in the gums. He experienced the same sensation when he again separated the rods and brought them to a short distance from each other, but he could perceive no galvanic effect when he placed the rods (or wires) in such manner that the silver rod should touch the zinc or the zinc rod touch the piece of silver. He also ascribed to galvanic effect the well-known fact that the drinking of porter out of a pewter pot produces a more brisk sensation than when it is taken out of a glass vessel. In this instance, he says there is a combination of one metal and of two dissimilar fluids. In the act of drinking, one side of the pewter pot is exposed to the saliva and the humidity of the mouth, while the other metallic side is in contact with the porter. In completing the circuit, in the act of drinking, a brisk and lively sensation arises, which imparts an agreeable relish to the liquid. He likewise observed that the conducting power of silk thread depends greatly on its colour, or rather on the nature of its dye. When of a brilliant white, or a black, its conducting power is the greatest; while either a high golden yellow or a nut-brown renders it the best insulator. Human hair, when completely freed from everything that water could wash out of it, and then dried by lime and coated with lac, was equal to silk.

Robison’s last publication was made in 1804, one year before his death, and constituted the first part of a series which was to appear under the head of “Elements of Mechanical Philosophy.” This portion, together with some MSS. intended for the second part, and his principal articles contributed to the “Encyclopædia Britannica,” were collected in 1822 by Sir David Brewster, and published with notes in 4 vols. under the title of “System of Mechanical Philosophy.”

REFERENCES.--Playfair in “Transactions of the Royal Society of Edinburgh,” Vol. VII. p. 495; Stark’s “Biographia Scotica”; Philosophical Magazine, Vol. XIII. pp. 386–394 (Biogr. Memoir); Aikin’s “General Biography,” London, 1813, Vol. VIII; Dr. Gleig in Anti-Jacobin Magazine for 1802, Vol. XI; Chalmer’s “Biographical Dictionary,” London, 1816, Vol. XXV; Dr. Thomas Young, “Course of Lectures,” London, 1807, Vol. II. pp. 438, 444.

=A.D. 1793.=--Prof. Georg. Fred. Hildebrandt of Erlangen (1764–1816), makes important observations relative to the influence of form and of substance upon the electric spark. He finds, among other results, that an obtuse cone with an angle of fifty-two degrees gives a much more luminous spark than one with an angle of only thirty-six degrees; that the greatest sparks are given by conical pieces of regulus of antimony and the least by tempered steel; also, that when the spark is white by taking it with a metallic body, it will, under the same circumstances, be violet if taken with the finger; that if the spark is taken with ice or water, or a green plant, its light will be red, and, if it is taken with an imperfect conductor, such as wood, the light will be emitted in faint red streams.

REFERENCES.--Biography in fifth ed. of “Lehrbuch der Physiologie des Mens. Koerpers,” Erlangen, 1817; “Encyl. Britannica,” Vol. VIII, 1855, pp. 544, 545; “Biog. Générale,” Vol. XXIV. pp. 671–672; Ersch und Gruber, “Allgem. Encyklopædie.”

=A.D. 1794.=--Read (John), mathematical instrument maker, at the Quadrant, in Kingsbridge, Hyde Park, gives, in his “Summary View of the Spontaneous Electricity of the Earth and Atmosphere,” the result of a very elaborate series of observations, which he continued almost hourly between the years 1791 and 1792. Of 987 trials, he found that 664 gave indications of positive electricity, and out of 404 trials made during twelve months, the air was positively electrical in 241, negatively in 156, and insensible in only seven observations. He also found the vapour near the ground, in the act of condensing into dew, always highly electric.

He made many observations upon the electricity of vegetable bodies, which were afterward developed by M. Pouillet, and it was also Mr. Read who introduced a new hand-exploring instrument as well as an improved fixed thunder rod for collecting atmospherical electricity. These are described at p. 608 of the eighth volume of the 1855 “Encyclopædia Britannica.”

According to Mr. Wilkinson (“Elements of Galvanism,” etc., London, 1804, Vol. II. p. 344), Mr. Read was the first to apply the apparatus called the condenser to the electroscope in order that it should evince small intensities of electricity. He says: “The very minute portion of the fluid given out by the single contact of two different metals, does not produce any disturbance of the gold leaves; but when several minute portions are accumulated, a separation of the leaves takes place. The electroscope, in its simple state, will be as much charged the first time as if the contact had been made a thousand times, and cannot therefore acquire a greater quantity of the fluid than suffices to place it in equilibrio with the metallic plates. This portion being inadequate to the production of any divergency of the leaves, Mr. Read applied the principle of the electrical doubler to the above instrument, by which means he was enabled to charge an intervening plate of air. By thus accumulating every minute portion of the fluid imparted through the metallic plate, and by apparently condensing and increasing its intensity, he ultimately succeeded in producing marked signs of disturbance.”

REFERENCES.--Philosophical Transactions for 1791, p. 185; for 1792, p. 225; for 1794, pp. 185, 266: also Hutton’s abridgments, Vol. XVII. pp. 52, 207, 423; “Bibl. Britan.,” Vol. II, 1796, p. 209; Vol. III, 1796, p. 272; Vol. X, an. vii. p. 283; Cavallo, “Nat. Phil.,” 1825, Vol. II. p. 226; Young’s “Course of Lectures,” Vol. I. p. 714; Ed. Peart, “On Electric Atmospheres ...” Gainsboro’, 1793; “Eng. Ency.,” “Arts and Sciences,” Vol. III. p. 805; Thomas Thomson, “Outline of the Sciences,” 1830, p. 446; Journal de Physique for 1794, Vol. XLV. p. 468.

=A.D. 1794.=--Chladni (Ernst Florens Friedrich), founder of the theory of acoustics, publishes “The Iron Mass of Pallas,” etc. (“Ueber den Ursprung der von Pallas ...”), giving a list of recorded cases of the fall of meteorites or aerolites and all the important accounts of such that he was able to collect. As Prof. Alexander Herschel informs us, in his lecture, delivered (1867) before the British Association at Dundee, Chladni conceived that a class of cosmical bodies exists in all parts of the solar system, each forming by itself a peculiar concourse of atoms, and that the earth from time to time encounters them, moving with a velocity as great as its own, and doubtless in orbits of very various eccentricity around the sun. Prof. Muirhead says that through their exceeding great velocity, which is increased by the attraction of the earth and the violent friction of the atmosphere, a strong electricity and heat must necessarily be excited, by which means they are reduced to a flaming and melted condition, and great quantities of vapour and different kinds of gases are thus disengaged, which distend the liquid mass to a monstrous size, until, by still further expansion of these elastic fluids, they must at length explode (Chladni’s hypothesis in “Enc. Brit.,” article “Meteorolite”).

Humboldt gives (“Cosmos,” London, 1849, Vol. I. p. 104, note) the following upon the same subject, taken from Biot’s “Traité d’Astronomie Physique,” third edition, 1841, Vol. I. pp. 149, 177, 238, 312: “My lamented friend Poisson endeavoured in a singular manner to solve the difficulty attending an assumption of the spontaneous ignition of meteoric stones at an elevation where the density of the atmosphere is almost null. These are his words: ‘It is difficult to attribute, as is usually done, the incandescence of aerolites to friction against the molecules of the atmosphere, at an elevation above the earth where the density of the air is almost null. May we not suppose that the electric fluid, in a neutral condition, forms a kind of atmosphere, extending far beyond the mass of our own atmosphere, yet subject to terrestrial attraction, although physically imponderable, and consequently following our globe in its motion?’ According to his hypothesis, the bodies of which we have been speaking would, on entering this imponderable atmosphere, decompose the neutral fluid by their unequal action on the two electricities, and they would thus be heated, and in a state of incandescence, by becoming electrified” (Poisson, “Rech. sur la Probabilité des Jugements,” 1837, p. 6).

The theories advanced by Chladni were confirmed four years later by Brandes and Benzenberg at Göttingen, and, during the month of April 1809, he inserted a “Catalogue of Meteors” in the “Bulletin de la Société Philomathique,” which was followed by a paper on “Fiery Meteors” published at Vienna during 1819.

In his “Traité d’Acoustique,” Chladni treats of the line of experiments to which he was led, as well by the discovery of Lichtenberg’s electrical figures (see A.D. 1777, and Tyndall, “Sound,” Lecture IV), an account of which latter appeared in the “Mémoires de la Société Royale de Göttingen,” as through the suggestions made him by Lichtenberg himself during the year 1792 relative to the origin of meteors. The results of Chladni’s researches concerning the last named appeared in a Memoir published at Leipzig during 1794, translated by M. Eugène Coquebert Mombret for Vol. V of the Journal des Mines.

It may here be properly added that, in one of the editions of his “Lectures on Sound,” Prof. Tyndall gives a portrait of Chladni and quotes a letter received from Prof. Weber wherein he says: “I knew Chladni personally. From my youth up he was my leader and model as a man of science, and I cannot too thankfully acknowledge the influence which his stimulating encouragement during the last years of his life had upon my own scientific labours.”

REFERENCES.--Quetelet (Lambert A. J.) in “Cat. Sc. Pap. Roy. Soc.,” Vols. V, VI, VIII; “Mém. de l’Acad. Roy. de Brux.,” 1830–1842; “Annali” of Ambroglio Fusinieri for 1854; “Phil. Mag.,” 1851; Secchi (Angelo) in “Cat. Sc. Pap. Roy. Soc.,” Vols. V, VIII; “Bull. Meteor. dell Osservat.,” 1862, 1866, 1867; Humboldt’s “Cosmos,” London, 1849, Vol. I. p. 104 (M. Schreiber), pp. 113, 114 (M. Capocci), also pp. 105, 108, 110, 121, and the entire “Review of Natural Phenomena,” with all the important references and notes thereunto attached. See likewise Peter Simon Pallas (Phil. Trans. for 1776 and “Act. Acad. Petrop.,” I for 1778); Chladni’s “Uber ... elektricität einer Katze,” Jena, 1797; J. Acton and Capel Lofft, in Phil. Mag., Vol. LI. pp. 109, 203; A Seguin, Phil. Mag., Vol. XLIV. p. 212; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. pp. 714, 762, for étoiles, filantes et météorites; F. B. Albinus, “Specimen,” etc., 1740; Voigt’s “Magaz.,” I, 1797; Schweigger’s Journal, XLIII, 1825; H. Atkinson, “On Hypotheses,” etc. (Phil. Mag., Vol. LIV. p. 336); Karstner, Archiven, Vol. IV; F. C. Von Petersdorff in “Great Divide”; Pierre Prevost and others in Poggendorff’s Annalen, Vols. II, VI and VII; Arago, “Annuaire pour 1826”; “The fall of Meteorites in Ancient and Modern Times” (“Sc. Progress,” Vol. II. N.S., pp. 349–370: numerous references given by Prof. H. A. Miers; “A Century of the Study of Meteorites,” by Dr. Oliver C. Farrington in “Pop. Sc. Monthly,” Feb. 1901, or the Report of Smiths. Instit. for 1901, pp. 193–197; Phil. Mag., Vol. IV. p. 332; “Cat. Sc. Papers ... Roy. Soc.,” Vol. I. pp. 916–918; D. Avelloni “Lettera,” etc., Venezia, 1760; Martin H. Klaproth’s different memoirs published at Berlin 1795–1809; Joseph Izarn, “Lithologie Atmosphérique”; J. Murray (Phil. Mag., Vol. LIV. p. 39); beside Chladni’s works in conjunction with Karl F. Anton von Schreibers, Wien, 1819 and 1820, and with Messrs. Steininger and Næggerath, London, 1827 (Schweigger’s Journal, N.R., XVI. 385, and Phil. Mag., Vol. II. p. 41, also Vol. IV. p. 332). For a very interesting account, see “A description of the great Meteor which was seen on the 6th of March 1715–1716, sent in a letter ... to R. Danuye ...” London, 1723 (Phil. Trans. for 1720–1721, Vol. XXXI), by Roger Cotes (1682–1716), of whom Sir Isaac Newton entertained so high an opinion as to frequently remark: “If Mr. Cotes had lived, we had known something” (“Biographia Philosophica,” pp. 512–516; English Encycl., “Biography,” Vol. II. p. 401). Other exceedingly interesting accounts of aerolites are to be found, more particularly in Frederic Petit’s works, published at Toulouse, in Bigot de Morogue’s “Catalogue,” London, 1814, and in the Phil. Mag., Vols., XVII, XX, XXVIII, XXXII, XXXVI, XLIII, XLVI, XLVIII, L, LIII, LIV, LVI-LIX, LXII. While treating of this subject, it may be well to add here that up to the year 1887 diamonds were not known to exist in meteorites. In a very remarkable paper by Prof. A. E. Foote, read before the Geological section of the Am. Asso. Adv. Sci., at its meeting in Washington, he described having, during the month of June 1891, explored Crater Mountain (Cañon Diablo), 185 miles north of Tucson, Ariz., where he found some extraordinary specimens. The extreme hardness of one of these attracted particular attention, and upon carefully examining it he discovered in some of the cavities many small black diamonds as well as a white diamond one-fiftieth of an inch in diameter. This is said to be the most extensive find of the kind yet made.

=A.D. 1794.=--Mr. J. Churchman publishes his improved “Magnetic Atlas or Variation Charts of the whole terraqueous globe,” etc., which Sir John Leslie subsequently pronounced the most accurate and complete hitherto made. The charts preceding it worthy of note were those of Dr. Halley (see A.D. 1683), of Mountaine and Dodson, in 1744 and in 1756, of Wilcke, in 1772, and of Lambert, in 1779. In his charts, Churchman refers variation lines to two poles, one of which he places, for the year 1800, in lat. 58° N. and long. 134° W. of Greenwich, while the other pole is in lat. 58° S. and long. 165° E. of Greenwich. He supposes the northern pole to revolve in 1096 years and the southern one in 2289 years (“Ency. Brit.,” 1857, Vol. XIV. p. 49).

REFERENCES.--Churchman’s letters to Cassini, Phila., 1788, and his “Explanation of the Magn. Atlas ...” 1790; Harris, “Rudim. Mag.,” Part III. p. 101; “Bibl. Britan.,” Vol. II. 1796, p. 325 (atlas); Becquerel, “Traité d’Electr. et de Magn.,” Paris, 1856, III. p. 140.

=A.D. 1794.=--M. Reusser Reiser, of Geneva, addresses a letter to the “Magazin für das Neueste aus der Physik” of Johann Heinrich Voigt (Vol. IX. part i. p. 183), describing the construction of “a new species of electric letter post” (“Schreiben an den herausgeber”) in the following words: “... on an ordinary table is fixed, in an upright position, a square board, to which a glass plate is fastened. On this plate are glued little squares of tinfoil, cut after the fashion of luminous panes, and each standing for a letter of the alphabet. From one side of these little squares extend long wires, enclosed in glass tubes, which go underground to the place whither the despatch is to be transmitted. The distant ends are there connected to tinfoil strips, similar ... to the first, and, like them, each marked by a letter of the alphabet; the free ends of all the strips are connected to one return wire, which goes to the transmitting table. If, now, one touches the outer coating of a Leyden jar with the return wire, and connects the inner coating with the free end of that piece of tinfoil which corresponds to the letter required to be indicated, sparks will be produced, as well at the near as at the distant tinfoil, and the correspondent there watching will write down the letter....”

Reusser also suggested calling the attention of the correspondent by firing an electrical pistol through the spark; to him, therefore, belongs the credit of having first clearly indicated the use of a special call for the telegraph.

REFERENCES.--Vail’s “History,” p. 121; Voigt’s “Magazin ...” Vol. VII. part ii. p. 57; Shaffner, “Manual,” pp. 133, 134; Forster’s “Bauzeitung,” 1848, p. 238; Ed. Highton, p. 38; Sabine, p. 11; “Appleton’s Encycl.,” 1871, Vol. XV. p. 335; Reiser, “Der El. Würfel,” Gotha, 1791; Comptes Rendus, Tome VII for 1838, p. 80.

=A.D. 1794.=--Prof. Boeckmann improves upon Reusser’s idea, and does away with the thirty-six plates and the seventy-two wires which the latter is believed to have employed. As Dr. Schellen expresses it, he used “the sparks passing at the distant station, employing only two wires, through which first one and then, after certain intervals, more sparks are combinedly grouped” in a way to indicate particular letters. Like Reusser, he made use of the pistol as a call signal.

REFERENCES.--Zetzsche, “Geschichte der Elektrischen Telegraphie,” p. 32; Boeckmann, “Versuch über Telegraphie und Telegraphen,” Carlsruhe, 1794, p. 17; “El. Magn. Teleg.,” 1850, p. 46; Gren’s Journal der Physik, Vol. I for 1790; “Neue Abhandl. der Bairischen Akad. Philos.,” Vol. III.

=A.D. 1794.=--Edgeworth (Richard Lovell), an able English mechanical philosopher, better known as the father and literary associate of Maria Edgeworth, introduces his tellograph (contraction of the word telelograph), “a machine describing words at a distance,” which originated in a wager relative to the prompt transmission of racing news from Newmarket to London. It consisted merely of four pointers, in the form of wedges or isosceles triangles, placed upon four portable vertical posts and the different positions of which were arranged to represent letters and numbers.

Edgeworth claimed to have made experiments, as early as 1767, with an ordinary windmill, the arms and sails of which were arranged in different positions to indicate the several letters of the alphabet.

REFERENCES.--Edgeworth’s Letter to Lord Charlemont on the Tellograph, also his “Essay on the Art of Conveying Secret and Swift Intelligence,” Dublin, 1797, republished in Vol. VI of the Trans. of the Royal Irish Academy; “Appleton’s Encycl.,” 1871, Vol. XV. p. 334.

A.D. 1795.--Lord George Murray, of England, submits to the Admiralty his six-shutter telegraph, an improvement upon Chappe’s original plan. Each of the six octagonal shutters was made to turn inside of two frames at different angles upon its own axis, thus affording sixty-three separate and distinct signals. By its means, information was transmitted from London to Dover in seven minutes, and it answered nearly all the requirements of the Admiralty up to the year 1816, when it was superseded by the semaphore of Rear Admiral Popham. Murray’s method was, however, useless during foggy weather, when relays of horses had to be employed for conveying the news.

REFERENCES.--English Encyclopædia, “Arts and Sciences,” Vol. VIII. p. 66; Tomlinson’s “Telegraph”; Turnbull, El. Mag. Tel., 1853, p. 18; “Penny Ency.,” Vol. XXIV. p. 147.

=A.D. 1795.=--Salvá (Don Francisco), a distinguished Spanish physician, reads a memoir, before the Academy of Sciences of Barcelona, from which the following is extracted: “... with twenty-two letters, and even with only eighteen, we can express with sufficient precision every word in the language, and, thus with forty-four wires from Mataro to Barcelona, twenty-two men there, each to take hold of a pair of wires, and twenty-two charged Leyden jars here, we could speak with Mataro, each man there representing a letter of the alphabet and giving notice when he felt the shock.... It is not necessary to keep twenty-two men at Mataro nor twenty-two Leyden jars at Barcelona, if we fix the ends of each pair of the wires in such a way that one or two men may be able to discriminate the signals. In this way six or eight jars at each end would suffice for intercommunication, for Mataro can as easily speak with Barcelona as Barcelona with Mataro ... or the wires can be rolled together in one strong cable ... laid in subterranean tubes, which, for greater insulation, should be covered with one or two coats of resin.”

He is said to have approved of the use of luminous panes as indicated by Reusser; to have also suggested, as early as December 16, 1795, the idea of a submarine telegraphic cable carrying several conductors, and to have proposed, at the same period, the laying of a cable between Barcelona and Palma in the island of Majorca.

In 1798, Salvá constructed a single wire telegraphic line between Madrid and Aranjuez, a distance of twenty-six miles, through which the signals were transmitted in the shape of sparks from Leyden jars. This is the line which is credited to Augustin de Bétancourt, a French engineer, by Alexander Von Humboldt, in a note at p. 14 of Gauss and Weber’s Resultate, etc., for the year 1837.

On the 14th of May 1800, and on the 22nd of February 1804, Salvá communicated to the Academy of Sciences at Barcelona two papers on galvanism applied to electricity, wherein he shows that a cheaper motive power is produced by the electricity of a number of frogs, and proposes a telegraphic apparatus in conjunction with the voltaic column which is illustrated and described at pp. 224 and 225 of Fahie’s “History of Telegraphy.” From the latter the following is taken: “This illustrious Spanish physician (Salvá) was therefore the first person who attempted to apply electricity dynamically for the purpose of telegraphing. It is, says Saavedra, not without reason, I must confess, notwithstanding my cosmopolitan opinions on scientific questions, that the Catalans hold Salvá to be the inventor of electric telegraphy. With documents as authentic as those which I have seen with my own eyes in the very hand writing of this distinguished professor (which documents are at this present moment to be found in the library of the Academy of Sciences of Barcelona) it is impossible for any author to henceforth deny, even if others did precede Salvá in telegraphic experiments with static electricity, that no one preceded him in the application of the docile electro-dynamic fluid to distant communications.”

REFERENCES.--Comptes Rendus, séance, 1838; Memorial of Joseph Henry, 1880, p. 224; Ed. Highton, the El. Tel., 1852, pp. 38 and 43; “Appleton’s Encyclopædia,” 1871, Vol. XV. p. 335; De Bow’s Review, Vol. XXV. p. 551; Voigt’s Magazin, etc., Vol. XI. part iv. p. 61; Sc. Am. Supp., No. 547, p. 8735, and No. 384, p. 6127; Biography in Saavedra’s Revista, etc., for 1876; Noad’s Manual, pp. 747 and 748; Shaffner, Manual, p. 135; Turnbull, El. Mag. Tel., 1853, pp. 21, 22, 220; Du Moncel, Exposé, Vol. III; “Edinburgh Encyclopædia,” London, 1830, Vol. VIII. p. 535; “Gazette de Madrid” of November 25, 1796; “Mémoires de l’Institut,” Vol. III and “Bulletin de la Soc. Philom.,” An. VI for the new telegraph of MM. Bréguet and Bétancourt, and for the Report made thereon by MM. Lagrange, Laplace and others.

=A.D. 1795.=--Ewing (John), D.D., Provost of the University of Pennsylvania and one of the founders of the American Philosophical Society, makes a compilation of his course of lectures on natural experimental philosophy, which is subsequently revised for the press by Prof. Robert Patterson.

He devotes much attention to atmospheric electricity, detailing the Franklinian theory, and, besides reporting upon the hypotheses advanced by Henry Eales (at A.D. 1755), as well as treating of the attraction of magnetism, he gives a very interesting account of experiments with the torpedo and the gymnotus electricus. He says that Mr. Walsh found the torpedo “possessed of the power of shocking only in two parts of its body, directly opposite to each other and near to the head. A spot on the back and another on the belly opposite to the former being of a different colour led him to make the experiment, and he found that the electrical virtue was confined to these, and that any other part of the fish might be handled, without receiving a shock, while it was out of the water. Either of these places separately might be handled without the shock being received until a communication between them was formed. This makes it appear probable that the same may also be the case with the Guiana eel. One of these spots must therefore be always in the positive and the other in the negative state; or, rather, they are both generally in the natural state, until, by an effort of the fish’s will, they are suddenly put into different states, as we frequently found that the hand might be in the water, which formed the communication, without receiving any shock. This cannot be the case with the Leyden bottle when charged, which suddenly discharges itself upon forming the communication. Whether there be any electric atmosphere round these spots in the torpedo we cannot tell, as we had no opportunity of examining this matter in the eel, nor have we heard whether Mr. Walsh made any experiments for ascertaining this.”

ELECTRICITY OF THE ATMOSPHERE

The investigations of John Ewing concerning atmospheric electricity were in reality quite extensive. He not only repeated the experiments of Franklin, but he examined thoroughly those of other scientists in the same channel, especially the investigations of Henry Eeles, which will be found detailed in the latter’s “Trinity College Lectures” as well as in his “Philosophical Essays,” London, 1771.

For a very interesting historical review of theories as to the origin of atmospherical electricity, it would be well to consult M. A. B. Chauveau’s article in “Ciel et Terre,” Bruxelles, March 1, 1903, and also Humboldt’s “Cosmos,” London, 1849, Vol. I. pp. 342–346. In the last-named work are cited: Arago, “Annuaire,” 1838, pp. 246, 249–266, 268–279, 388–391; Becquerel, “Traité de l’Electricité,” Vol. IV. p. 107; De la Rive, “Essai Historique,” p. 140; Duprez, “Sur l’électricité de l’air,” Bruxelles, 1844, pp. 56–61; Gay-Lussac, “Ann. de Ch. et de Phys.,” Vol. VIII. p. 167; Peltierin, “Ann. de Chimie,” Vol. LXV. p. 330, also in “Comptes Rendus,” Vol. XII. p. 307; Pouillet, “Ann. de Chimie,” Vol. XXXV. p. 405.

------+-----------------+-------------------------------+--------------------------- | | | Date | Name | Experiments | References | | | ------+-----------------+-------------------------------+--------------------------- 1751 |Franklin |Effects of lightning |Phil. Trans., xlvii. p. 289 ------+-----------------+-------------------------------+--------------------------- 1751 |Mazeas |Kite experiments independently |Phil. Trans., 1751–1753 | | of Franklin | ------+-----------------+-------------------------------+--------------------------- 1752 |Nollet |Theory of Electricity |Recher. sur les causes, | | | 1749–1754 | | |Lettres sur l’élect., 1753, | | | 1760, 1767, 1770 ------+-----------------+-------------------------------+--------------------------- 1752 |Watson |Electricity of clouds |Phil. Trans., 1751, 1752 ------+-----------------+-------------------------------+--------------------------- 1752 |De Lor and Buffon|Iron pole 99 ft. high, mounted |Letter of Abbé Mazeas, | | on a cake of resin 2 ft. sq.,| dated St. Germain, | | 3 in. high, Estrapade, May | May 20, 1742 | | 18, 1752 | ------+-----------------+-------------------------------+--------------------------- 1752 |D’Alibard |Sparks from thunder clouds, 40 |Mem. l’Acad., r. des | | ft. pole in garden at Marly, | Sci., May 13, 1762 | | also wooden pole 30 ft. high,| Hist. Abrégée, 1776 | | at Hôtel de Noailles | ------+-----------------+-------------------------------+--------------------------- 1752 |Le Monnier |Observations of air charge |Mém. de Paris, 1752, | | | pp. 8, 233 ------+-----------------+-------------------------------+--------------------------- 1752 |De Romas |Observations of air charge; |Mém. Sav. Etrangers, | | kite experiments | 1752, and Mém. de | | | Math., 1755, 1763 ------+-----------------+-------------------------------+--------------------------- 1752 |Mylius, Ch. |Observations of air charge |“Nachrichten,” Berlin, 1752 | | | ------+-----------------+-------------------------------+--------------------------- 1752 |Kinnersley |Observations of air charge |Franklin’s Letters, Phil. | | | Trans., 1763, 1773 ------+-----------------+-------------------------------+--------------------------- 1752 |Ludolf and Mylius|Observations of air charge |Letter to Watson ------+-----------------+-------------------------------+--------------------------- 1753 |Richman |Electrical gnomon |Phil. Trans., 1753 ------+-----------------+-------------------------------+--------------------------- 1753 |Canton |Electricity of clouds |Franklin’s letters and | | | Phil. Trans., 1753 ------+-----------------+-------------------------------+--------------------------- 1753 |Beccaria, C.B. |Systematic observations with |Lett. dell’ Elet. Bologna, | | an electroscope | 1758 ------+-----------------+-------------------------------+--------------------------- 1753 |Wilson |Experiments |Phil. Trans., 1753, p. 347 ------+-----------------+-------------------------------+--------------------------- 1754 |Lining |Kite experiments |Letter to Chas. Pinckney ------+-----------------+-------------------------------+--------------------------- 1755 |Le Roy |Experiments |Mém. de Paris, 1755 ------+-----------------+-------------------------------+--------------------------- 1756 |Van Musschenbroek|Kite experiments |Intro. ad Phil. Nat., 1762 ------+-----------------+-------------------------------+--------------------------- 1759 |Hartmann |Origin of electricity |Verbesseter ... Blitzes | | | (Hamb. Mag. vol. xxiv.) ------+-----------------+-------------------------------+--------------------------- 1769 |Cotte |Memoirs on meteorology |Journ. Phys., xxiii., 1783 | | | Mém. Paris, 1769–1772 ------+-----------------+-------------------------------+--------------------------- 1772 |Ronayne |Fog observations |Phil. Trans., 1772, p. 137 ------+-----------------+-------------------------------+--------------------------- 1772 |Henley |Quadrant electrometer |Phil. Trans., 1772–1774 ------+-----------------+-------------------------------+--------------------------- 1775 |Cavallo |Fogs, snow, clouds and rain; |Treatise on Elect., 1777 | | kite experiments | ------+-----------------+-------------------------------+--------------------------- 1784 |De Saussure |Observations |“Voyages dans les Alpes,” | | | Geneva, 1779–1796 ------+-----------------+-------------------------------+--------------------------- 1786–7|Mann |Daily observations with an |Ephémer. Météorol. of the | | electrical machine, timing | Mannheim Society, | | the revolutions to produce a | 1786–1792 | | given spark with a record of | | | the weather | ------+-----------------+-------------------------------+--------------------------- 1788 |Volta |New electroscope |Lettere Sulla Meteor, | | | 1788–1790 ------+-----------------+-------------------------------+--------------------------- 1788 |Crosse |Experiments with collectors |Gilb. Ann., Bd. 41, s. 60 ------+-----------------+-------------------------------+--------------------------- 1791 |Read |Insulation and conductors |Phil. Trans., 1791 and | | | Summary, 1793 ------+-----------------+-------------------------------+--------------------------- 1792 |Von Heller |Observations |Gren, “Neues Journ. der | | | Phys.,” vol. ii. 1795 | | | and vol. iv. 1797 ------+-----------------+-------------------------------+--------------------------- 1792 |Schubler |Observations with weather rod |J. de Phys., lxxxiii. 184 ------+-----------------+-------------------------------+---------------------------

An attractive table, which we are permitted to rearrange and reproduce here, giving a résumé of references to some of the most noted experiments of the chief investigators from the time of Franklin to the end of the eighteenth century, was made up by Mr. Alex. McAdie and first appeared in the “Amer. Meteor. Journal.” Mr. McAdie says that a detailed history of most of Franklin’s co-labourers will be found in the accounts given by Exner,[53] Hoppe,[54] Mendenhall,[55] Elster and Geitel[56] as well as by himself,[57] and that in making up this table he has passed over Peter Collinson, of London, who introduced to the notice of the Royal Society the experiments of Franklin, and the three less-known workers--J. H. Winkler, who wrote in 1746 on the electrical origin of the weather lights; Maffei, 1747; and Barberet, 1750.

=A.D. 1795.=--The telegraphs of the Rev. J. Gamble, Chaplain to the Duke of York, consisted either of five boards placed one above the other or of arms pivoted at the top of a post upon one axis and capable of producing as many signals as there are permutations in the number five, all of the combinations being possible at equal angles of forty-five degrees. His doubts as to the practicability of employing electricity “as the vehicle of information” are fully expressed at p. 73 of his “Essay on the Different Modes of Communicating by Signal,” etc., London, 1797.

REFERENCES.--J. Gamble, “Observations on Telegraphic Experiments,” etc.; Article “Telegraph” in Tomlinson’s “Encyl. of Useful Arts”; “Penny Ency.,” Vol. XXIV. pp. 147 and 148; “English Cyclopædia,” “Arts and Sciences,” Vol. VIII. p. 66.

=A.D. 1795.=--Garnet (John), proposes a telegraph consisting of only one bar moving about the centre of a circle, upon which latter the letters and figures are inscribed. On placing corresponding divisions, by means of wires, before the object glass of the telescope the coincidence of the two radii or of the arm would point out the letter intended to be repeated. As this plan proved impracticable for long distances, it did not come into general use (“Emporium of Arts and Sciences,” Phila., 1812, Vol. I. p. 293).

=A.D. 1795.=--Wells (Charles William), a physician, native of South Carolina but practising in England and a F.R.S., publishes in the Phil. Trans. a paper on the influence which incites the muscles of animals to contract in Galvani’s experiments. Therein he was the first to demonstrate that voltaic action is produced through charcoal combined with another substance of different conducting power, and this he did by causing noticeable convulsions in a frog through the combination of charcoal and zinc. (See “Ency. Met.,” Vol. IV. pp. 220, 221, for the experiments of both Dr. Wells and Dr. Fowler.) Fahie states that Davy subsequently constructed a pile which consisted of a series of eight glasses containing well-burned charcoal and zinc, using a red sulphate of iron solution as the liquid conductor. It is said this series gave sensible shocks and rapidly decomposed water and that, compared with an equal and similar series of silver and zinc, its effects were much stronger. (See Priestley’s discovery of the electrical conductibility of charcoal at A.D. 1767, and the description of Davy’s charcoal battery in “Jour. Roy. Inst.” and Nicholson’s Journal, N. S., Vol. I. p. 144.)

His biographer, in the “Eng. Cyclop.,” says (Vol. VI. pp. 631–632) that his last work and the one upon which his reputation as a philosopher must rest, is his “Essay upon Dew,” published in 1814 (“Journal des Savants” for Sept. 1817), whilst J. F. W. Herschel remarks at p. 122 of his “Prel. Disc ... Nat. Phil.,” 1855: “We have purposely selected this theory of dew, first developed by the late Dr. Wells, as one of the most beautiful specimens we can call to mind of inductive experimental inquiry lying within a moderate compass....”

REFERENCES.--Wells’ biography in the “English Cyclopædia,” Vol. VI. p. 631; Phil. Trans. for 1795, p. 246; Hutton’s abridgments of the Phil. Trans., Vol. XVII. p. 548; Fahie’s “History,” etc., pp. 201 and 202; “Aristotle on Dew” (Poggendorff, Geschichte der Phys., 1879, p. 42); Luke Howard, “On the Modification of Clouds ...” London, 1803; C. H. Wilkinson, “Elements of Galvanism,” etc., London, 1804, Vol. I. pp. 162–165 and Vol. II. p. 329.

=A.D. 1796.=--Gregory (George), D.D., F.R.S., Vicar of Westham, a miscellaneous writer of Scotch origin, for many years editor of the “New Annual Register,” is the author of “Economy of Nature,” etc., of which the second and third editions, considerably enlarged, appeared respectively in 1798 and 1804.

In the first volume of the last-named edition (Book I. chap. vi. pp. 35–54) he treats of natural and artificial magnets and of magnetic powers and theories of magnetism, while the whole of Book IV. (chaps. i.-viii. pp. 299–386) is devoted to the history of and discoveries relative to electricity, its principles and theories, as well as to electrical apparatus and electrical phenomena and to galvanism or animal electricity.

Gregory is also the author of “Popular Lectures on Experimental Philosophy, Astronomy and Chemistry; Intended Chiefly for the Use of Students and Young Persons,” 2 vols., 12 mo, published in London 1808–1809, one year after Gregory’s death.

It was the perusal of the latter work which led Joseph Henry to embrace a scientific career, just as the reading of “Mrs. Marcet’s Conversations on Chemistry” had induced Michael Faraday to enter the field in which he afterward became so highly distinguished. Prof. Asa Gray, in his Biographical Memoir of Henry, says that Gregory’s work alluded to is an unpretending volume but a sensible one, and that it begins by asking three or four questions, such as these: “You throw a stone, or shoot an arrow into the air; why does it not go forward in the line or direction that you give it? Why does it stop at a certain distance and then return to you?... On the contrary, why does flame or smoke always mount upward, though no force is used to send them in that direction? And why should not the flame of a candle drop toward the floor when you reverse it, or hold it downward, instead of turning up and ascending into the air?... Again, you look into a clear well of water and see your own face and figure as if painted there? Why is this? You are told that it is done by reflection of light. But what is reflection of light?” As Prof. Gray remarks, young Henry’s mind was aroused by these apt questions, and allured by the explanations. He now took in a sense of what knowledge was. The door to knowledge opened to him, that door which it thence became the passion of his life to open wider. The above-named volume is preserved in Prof. Henry’s library, and bears upon a fly-leaf the following entry:

“This book, although by no means a profound work, has, under Providence, exerted a remarkable influence upon my life. It accidentally fell into my hands when I was about sixteen years old, and was the first work I ever read with attention. It opened to me a new world of thought and enjoyment; invested things before almost unnoticed with the highest interest; fixed my mind on the study of nature, and caused me to resolve at the time of reading it, that I would immediately commence to devote my life to the acquisition of knowledge. J. H.” (See Prof. A. M. Mayer, “Eulogy of Joseph Henry,” Salem, 1880, pp. 29–30; “Smithsonian Report,” 1878, pp. 145, 146.)

REFERENCES.--Gentleman’s Magazine, Vol. LXVII. p. 415; Beloe’s “Sexag.,” II. 128; “Living Authors” (1798), I. p. 225.

=A.D. 1797.=--Bressy (Joseph), French physician and able chemist, remarks, in his “Essai sur l’électricité de l’eau,” that the electric fluid is composed of three beams (rayons, i. e. rays, gleams, or sparks), vitreous, resinous and vital; that three principal agents exist in nature, viz. the air, isolating body; the water, conducting body, and movement, determining action; that vapours resolve themselves into clouds merely because friction enables the electric fluid to seize upon the aqueous molecules, and that, in water, the hydrogen is maintained in the form of gas by the electric fluid, while the oxygen becomes gaseous under influence of the caloric.

REFERENCES.--Larousse, “Dict. Univ.,” Vol. II. p. 1236; Delaunay, “Manuel,” etc., 1809, pp. 15, 16.

=A.D. 1797.=--Treméry (Jean Louis), a French mining engineer, communicates his observations on elliptic magnets through Bulletin No. 6 of the “Société Philomathique” as well as through the sixth volume of the Journal des Mines.

His observations on conductors of electricity and on the emission of the electric fluid appear at p. 168 Vol. XLVIII of the Jour. de Phys., and in “Bull. de la Soc. Philom.,” No. 19, while his views in opposition to the two-fluid theory are to be found in Bulletin No. 63 of the last-named publication as well as in Jour. de Phys., Vol. LIV. p. 357.

REFERENCES.--Poggendorff, Vol. II. p. 1131; John Farrar, “Elem. of Elec.,” etc., p. 120.

=A.D. 1797.=--Pearson (George), English physician and chemist, communicates to the Royal Society a very interesting paper entitled, “Experiments and Observations made with the view of ascertaining the nature of the gas produced by passing electric discharges through water; with a description of the apparatus for these experiments.”

An abstract of the above appears in the Phil. Trans. for 1797, and a full transcript of it is to be found in Nicholson’s Journal, 4to, Vol. I. pp. 241–248, 299–305, and 349–355.

As Mr. Wilkinson has it, “Dr. Pearson supposes the decomposition of water by electricity to be effected by the interposition of the dense electric fire, between the constituent elements of the water, which he places beyond the sphere of attraction for each other, each ultimate particle of oxygen and hydrogen uniting with a determinate quantity of the electric fire to bestow on them their gaseous form. Hence the doctor supposes that the electric fire, after effecting the disunion, assumes the state of caloric.

“On the reproduction of water by the passage of an electric spark through a proportionate quantity of oxygen and hydrogen gases, Dr. Pearson ingeniously conjectures that by the influence of the electric flame the ultimate particles of these gases, the nearest to the flame, are driven from it in all directions, so as to be brought within the sphere of each other’s attractions. In one of these cases Dr. Pearson supposes that the caloric destroys the attraction, which in the other instance it occasions.

“It is with diffidence that I take on me to controvert the opinions of this very respectable physician; but I presume that the whole of the phenomena of the synthesis and analysis of water are more readily to be explained on the principles I have laid down than by the adoption of the mysterious terms of attraction and repulsion. By the operation of galvanism, water is more rapidly decomposed than by common electricity. In this operation there is no evolution of dense electrical fire, but merely a current of a small intensity of electricity acting permanently and incessantly. To reproduce water, a flame must be generated sufficient to kindle the contiguous portion of the hydrogen gas, then the next portion, and so on, the combustion being preserved by the presence of the oxygen gas. As these processes proceed with immense rapidity as soon as the gases are intermixed, so as to appear like one sudden explosion, the caloric of each of them being thus disengaged, their bases unite and constitute water.”

Dr. Pearson also made many interesting experiments to ascertain the effect of the application of galvanic electricity for the treatment of diseases, and Noad, who describes one of his successful operations, also details (“Manual,” pp. 343–349) the observations of many others in the same line, notably those of Drs. Apjohn, Majendie, Grapengieser and of Wilson Philip, Petrequin, Pravaz, Prevost and Dumas (Jour. de Physiol., Tome III. p. 207), as well as of Sarlandière and Dr. Golding Bird, besides giving the very important conclusions arrived at by Stefano Marianini.

REFERENCES.--“Some Account of George Pearson,” M.D., F.R.S. (Phil. Mag., Vol. XV for 1803, p. 274); letter of Humboldt to M. Loder (“Bibl. Germ.,” Vol. IV, Messidor, An. VIII. p. 301); William Van Barneveld, “Med. Elektricität,” Leipzig, 1787; C. H. Wilkinson, “Elements of Galvanism,” London, 1804, 2 vols. passim; Paragraph No. 328 of Faraday’s “Experimental Researches,” J. N. Hallé, “Journal de Médecine de Corvisart,” etc., Tome I, Nivose, An. IX. p. 351; “Annales de l’Electricité Médicale” passim; H. Baker (Phil. Trans., Vol. XLV. p. 270); “Jour. de la Soc. Philom.,” Messidor, An. IX; J. F. N. Jadelot, “Expériences,” etc., 1799; M. Butet (“Bull. des Sc. de la Soc. Philom.,” No. 43, Vendémiaire, An. IX); M. Oppermanno, “Diss. Phys. Med.” (see J. G. Krunitz “Verzeichnis,” etc.); Andrieux, “Mémoire ... maladies,” Paris, 1824; Lebouyer-Desmortiers (Sue, “Hist. du Galv.,” Vol. II. p. 420, and Jour. de Phys., Prairial, An. IX, 1801, p. 467); C. J. C. Grapengieser, “Versuche den Galvanismus,” etc., Berlin, 1801 and 1802; the works of J. Althaus, published in London and Berlin in 1859–1870; C. A. Struve’s works, published in Hanover and Breslau, 1797–1805; F. L. Augustin’s works, published in Berlin, 1801–1803; Karl Friedrich Kielmeyer (Kielmaier), works published at Tübingen (Poggendorff, Vol. I. p. 1253); Einhoff (Gilbert, XII. p. 230); Francesco Rossi’s treatises on the application of galvanism, published in 1809; Gilb. “Ann.,” Vol. XII. p. 450; Jour. de Phys., Vol. LII. pp. 391 and 467; Cuthbertson’s letter in Phil. Mag., Vol. XVIII. p. 358; J. G. Anglade, “Essai sur le Galvanisme,” etc. (Sue, “Hist. du Galv.,” Vol. III. p. 73); Jacques Nauche, in Phil. Mag., Vol. XV. p. 368, as well as in Poggendorff, Vol. II. p. 256, and throughout the “Journal du Galvanisme.”

=A.D. 1797.=--In No. CCXXII of the Reichsanzeiger, a German publication, it is said that a certain person having an artificial magnet suspended from the wall of his study with a piece of iron adhering to it, remarked, for several years, that the flies in the room, though they frequently placed themselves on other iron articles, never settled upon the artificial magnet.

REFERENCES.--Cavallo, “Experimental Philosophy,” 1803, Vol. III. p. 560, or the 1825 Philad. ed., Vol. II. p. 286.

=A.D. 1797–1798.=--Reinhold (Johann Christoph Leopold), while Bachelor of Medicine in Magdeburg, tendered for his theses, on the 16th of December 1797 and on the 11th of March 1798, two Latin dissertations on galvanism, one of which was offered concurrently with J. William Schlegel, then a medical student.

Numerous extracts from both the above very important papers, which treat extensively of galvanic experiments upon animals, vegetables, metals, etc., will be found at pp. 123–195, Vol. I of Sue’s “Histoire du Galvanisme,” Paris, 1802. Both dissertations review galvanism from its origin and make mention of many works which had not up to that time appeared in print.

In the first volume of his “Elements of Galvanism,” London, 1804, Mr. C. H. Wilkinson devotes the entire Chap. VIII (pp. 188–260) to Reinhold’s able review of galvanism, wherein are first cited Gardiner (author of “Observations on the Animal Economy”), Lughi, Klugel and Gardini as “anterior to the discovery of the doctrine of animal electricity.” Then follow accounts of their writings, as well as of those of Galvani and of Volta, “the Prince of Italian naturalists,” after which due mention is made, in their proper order, of the observations of Aldini, Valli, Fontana, Berlinghieri, Monro, Fowler, Corradori, Robison, Cavallo, Wells, Havgk, Colsmann, Creve, Hermestædt, Klein, Pfaff, Ackermann, Humboldt (letters to Blumenbach, Crell, Pictet and M. de Mons), Eschenmeyer, Achard, Grapengieser, Gren, Michaelis, Caldani, Schmuck, Mezzini, Behrends, Giulio, Ludwig, Webster, Vasco, Hebenstreit and others.

The subject of the eighth and last section of Reinhold’s Dissertations, as Wilkinson expresses it, consists of the exposition of the hypotheses of different authors on the galvanic fluid. These hypotheses he brings into two classes, as they relate to the seat which is assigned to the cause of the phenomena. The first of these classes belongs to the animal which is to be galvanized, and the second to the substance applied to its body, or to the arc. As the galvanic phenomena are ascribed by several physiologists to electricity, Reinhold makes a new division, relatively to the opinion of those who assert that the galvanic and electric fluids are the same, and of those who are persuaded that the former differs from the latter. Under the first head or division he ranges Galvani, Aldini, Valli, Carradori, Volta, in the early time of the discovery; then Schmuck, Voigt, and Hufeland; while under the second come Fowler and Humboldt. Of the latter division he makes subdivisions, in the first of which he comprehends Volta, Pfaff, Wells, Yelin and Monro, the second embracing Creve and Fabbroni. The other authors, not having openly avowed their opinion, he passes over in silence.

Reinhold is likewise the author of “Versuche um die eigentliche,” etc. (Gilb. “Annal.,” X, 1802, pp. 301–355), “Untersuchungen über die natur.,” etc. (Gilb. “Annal.,” X, 1802, pp. 450–481, and XII, 1803, pp. 34–48); “Galvanisch-elektrische Versuche,” etc. (Gilb. “Annal.,” XI, 1802, pp. 375–387); “Geschichte des Galvanismus,” Leipzig, 1803; “Versuch einer skizzirten,” etc. (Reil. “Archiv.,” VIII, 1807–1808, pp. 305–354); “Ueber Davy’s Versuche” (Gilb. “Annal.,” XXVIII, 1808, pp. 484–485).

REFERENCES.--Schlegel, “De Galvanismo”; Figuier, “Exp. et Hist. des Principales Découvertes,” Vol. IV. pp. 310, 433; J. W. Ritter, “Beweis ... in dem Thierreich ...” Weimar, 1796; G. R. Treviranus, “Einfluss ... thier, Reizbarkeit,” Leipzig, 1801, and Gilbert’s “Annalen,” Vol. VIII for the latter year.

=A.D. 1798.=--Perkins (Benjamin D.), is given an English patent for a process enabling him to cure aches, pains and diseases in the human body by drawing electrified metals over the parts affected. His metallic tractors, originally introduced from America and consisting of an alloy of different metals, awakened much curiosity both in England and on the Continent, and were successfully used by Dr. Haygarth and others, as related in the article “Somnambulism,” of the “Encyclopædia Britannica.”

In the Repert. II. ii. 179, it is said that one of the tractors was made of zinc, copper and gold, and the other of iron, platina and silver. M. V. Burq, in his “Métallo-thérapie,” makes a review of the successful cures of nervous complaints effected by metallic applications.

REFERENCES.--Jour. de Phys., Vol. XLIX. p. 232; Mr. Langworthy, “View of the Perkinian Electricity,” 1798; T. G. Fessenden, “Poetical petition against ... the Perkinistic Institution ...” London, 1803; B. D. Perkins, “The Influence of Metallic Tractors on the Human Body ...” London, 1798–1799; “Bibl. Britan.,” Vol. XXI, 1802, pp. 49–89; “Recherches sur le Perkinisme,” etc. (“Annales de la Soc. de Méd. de Montpellier,” Vol. XXIX. p. 274); “Sur les tracteurs de Perkins” (“Mém. des Soc. Savantes et Lit.,” Vol. II. p. 237); P. Sue, aîné, “Hist. du Galv.,” IV. p. 286 and “Hist du Perkinisme,” Paris, 1805; J. D. Reuss, “De re electrica,” Vol. XII. p. 20; J. Krziwaneck, “De electricitate ...” Prag., 1839.

=A.D. 1798.=--In a long letter written to Thomas Jefferson, President of the American Philosophical Society, and read before the latter body on the 4th of May 1798, the Rev. James Madison, then President of William and Mary College, details several experiments made by him to ascertain the effect of a magnet upon the Torricellian vacuum, and to explain the phenomena exhibited by magnets in proximity to iron filings.

He says: “Many ingenious men have supposed that the arrangement of the filings clearly indicated the passage of a magnetic fluid or effluvia in curved lines from one pole to another of a different denomination,” but that the experiments which he relates prove the attractive force of the magnets, at either pole, to be the real cause of the phenomena which the filings exhibit, and that the action of the magnet upon the filings, when they approach within a certain distance, renders them magnetic. In every magnet, says he, there is at least one line, called the equator, from which, in the direction of both poles, the attractive power increases so that the filings will “incline toward them, forming angles which appear to be such as the resolution of two forces, one lateral and the other polar, would necessarily produce.”

Thomas Jefferson, above named, succeeded Benjamin Franklin as United States Minister Plenipotentiary to Paris, 1784–1789, became Vice-President of the United States in 1796, and was sworn in as the successor of John Adams to the Presidency on the 4th of March 1801. The Rev. James Madison, D.D., second cousin of the fourth President of the United States bearing the same name, became President of William and Mary College in 1777, and was consecrated first Bishop of Virginia by the Archbishop of Canterbury in Lambeth Palace, Sept. 19, 1790.

REFERENCES.--“Transactions of the Am. Phil. Soc.,” Vol. IV for 1799, O.S. No. 39, pp. 323–328.

=A.D. 1798.=--Monge (Gaspar), Comte de Peluse, a very able French scientist, called “the inventor of descriptive geometry,” and from whom, it is said, that science received greater accessions than had before been given it since the days of Euclid and Archimedes, erects a telegraph upon the “Palais des Tuileries” in Paris. Of this, however, no reliable details are on record.

He also makes many experiments on the effects of optics and electricity, and, likewise, many useful observations on the production of water by inflammable air, independently of those carried on by Lord Cavendish.

REFERENCES.--Biography in Charles Dupin’s “Essai Historique,” etc., and in “English Cycl.,” Vol. IV. pp. 296, 297; Memoir at p. 175 of Vol. LV, Phil. Mag. for 1820; G. Monge, “Sur l’effet des étincelles ...” Paris, 1786, and “Précis des leçons,” Paris, 1805; Sci. Am. Supp., No. 621, p. 9916, and the note at foot of p. 701 of “Fifth Dissert.” eighth ed. of “Encyclopædia Britannica,” Vol. I; as well as “Mém. de l’Acad. des Sciences,” 1786.

=A.D. 1798.=--Berton (Henri Montan), a prominent French composer and Professor of Harmony at the Paris “Conservatoire de Musique,” also a member of the “Académie des Beaux-Arts,” devises a novel electric telegraph which is merely alluded to, under the heading of “Note historique sur le télégraphe électrique,” at p. 80 of the seventh volume of the Comptes Rendus for July 1838, as well as in Julia Fontenelle’s “Manuel de l’électricité.”

=A.D. 1799.=--Fabbroni--Fabroni--(Giovanni Valentino M.), Professor of Chemistry at Florence, communicates to the Journal de Physique (9th series, Tome VI, Cahier de Brumaire, An. VIII), an amplification of his able memoir, “Sur l’action chimique,” etc. (“Dell’azione chimica ...”), which was first presented by him during 1792 to the Florentine Academy and duly analyzed by Brugnatelli in his “Giornale physico-medico.” Therein is made the first known suggestion as to the chemical origin of voltaic electricity, inquiring whether the phenomenon of galvanism is not solely due to chemical affinities of which electricity may be one of the concomitant effects, and also ascribing the violent convulsions in a frog to a chemical change which is produced by the contact of one of the metals with some liquid matter on the animal’s body, the latter decomposing and allowing its oxygen to combine with the metal.

REFERENCES.--“Elogio ... A. Lombardi” (“Mem. Soc. Ital.,” Vol. XX); Cornhill Magazine, Vol. II for 1860, p. 68; “Biog. Univ.,” Vol. XIII. p. 311; “Encycl. Met.,” “Galvanism,” Vol. IV. p. 215; Journal de Physique, Vol. XLIX. p. 348; “Chambers’ Ency.,” 1868, Vol. IV. p. 593; “Mem. Soc. Ital.,” Vol. XX. pp. 1 and 26; P. Sue, aîné, “Histoire du Galvanisme,” Paris, An. X-1802, Vol. I. pp. 229–232; Phil. Mag., Vol. V. p. 270; Nicholson’s Journal, quarto, Vol. IV. p. 120; Sir Humphry Davy, “Bakerian Lectures,” London, 1840, p. 49; Young’s “Lectures,” Vol. I. p. 752; W. Sturgeon, “Scientific Researches,” Bury, 1850, p. 156; “Giornale di fisica” for 1810; “Giornale dell’ Ital. Lettera ...” IX. p. 97; “Atti della Reg. Soc. Economica di Firenze,” XX. p. 26; Brugnatelli, _Annali di chimica_, II. p. 316 and XXI. p. 277; C. Henri Boissier, “Mémoire sur la décomp. de l’eau, etc.,” Paris, 1801 (_Journal de Physique_, Prairial, An. IX).

=A.D. 1799.=--Jadelot (J. F. N.), French physician, translates Humboldt’s work on “Galvanism,” wherein he reviews the investigations of the great German scientist and treats of the application of the Galvanic fluid in medical practice. The observations of a friend of Humboldt, Dr. C. J. C. Grapengieser, are especially detailed and a complete account is given of all the noted physicians who have recorded experiments in the same line.

REFERENCES.--For the medical applications of Galvanism: _Journal de Physique_, Vol. LII. pp. 391, 467; Gilbert’s “Annalen,” XI. 354, 488 and XII. 230, 450; “An. of Sc. Disc.” for 1865, p. 123; Larrey, 1793, 1840; L. Desmortiers, 1801; Legrave, 1803; F. J. Double, 1803; J. Nauche, 1803; “Galv. Soc.” (Phil. Mag., Vol. XV. p. 281); Laverine, 1803; Mongiardini and Lando, 1803; F. Rossi, 1803–1827; J. Schaub, 1802–1805; B. Burkhardt, 1802; M. Butet, 1801; J. Le Roy d’Etiolle, “Sur l’emploi du Galv....”; P. L. Geiger, 1802–1803; J. D. Reuss in “De Re Electrica”; M. Buccio, 1812; La Beaume, 1820–1848; P. A. Castberg (Sue, “Hist. du Galv.,” IV. 264); Fabré-Palaprat and La Beaume, 1828; Rafn’s “Nyt. Bibl.,” IV; C. C. Person, 1830–1853; S. G. Marianini, 1841; C. Usiglio, 1844; F. Hollick, 1847; G. Stambio, 1847; Du Fresnel, 1847; H. de Lacy, 1849; M. Récamier, J. Massé, 1851; R. M. Lawrance, Robt. Barnes, and Crimotel de Tolloy, 1853; M. Middeldorpf, 1854; R. Remak, 1856, 1860, 1865; J. Seiler, 1860; V. Von Bruns, 1870.

=A.D. 1799.=--Humboldt (Friedrich Heinrich Alexander, Baron Von) (1769–1859), native of Berlin, is the author of “Cosmos” so frequently alluded to in these pages, and, in the words of one of his biographers, “will be remembered in future times as perhaps, all in all, the greatest descriptive naturalist of his age, the man whose observations have been most numerous and of the widest range, and the creator of several new branches of natural sciences.”

The French translation of his work on “Galvanism” (“Expériences sur le Galvanisme ... traduit de l’allemand par J. F. N. Jadelot”) appeared in Paris during the year 1799, before which date, Noad remarks, no one had applied the galvanic arc, as he did, to so many animals in various parts of their bodies. Among other results, he discovered the action of the electric current upon the pulsation of the heart, the secretions from wounds, etc., and he proved upon himself that its action was not limited to the sole instants of the commencement and end of its passage.

In the first volume of his very interesting work on “Galvanism” (pp. 166–174, 261–310, 407–434) Wilkinson reviews the above-named publication which M. Vassalli-Eandi, in 1799, pronounced “the most complete that has hitherto appeared.” The following sectional extracts are mainly taken from Mr. Wilkinson’s book, Chap. IX. part ii. Humboldt’s first experiments were made with the aid of M. Venturi, Professor of Natural Philosophy at Modena, and they were followed quite assiduously for a while, but it was not until he learned of the important observations made by Fowler, Hunter and Pfaff on animal electricity and irritability, that he was spurred on to still further extended investigations, which were carried on more particularly in presence of Jurine, Pictet, Scarpa, Tralles and Volta. Humboldt’s work is divided into ten sections, as follows:

Sect. I treats of the relation between galvanic irritation and incitability.

Sect. II deals with the galvanic irritation produced without a coating, or metallic or charcoal substances (repeating the investigations of M. Cotugno, which led to the experiments of Vassalli during 1789).

Sect. III treats of the excitement produced by a simple metallic substance, or by homogeneous metallic parts (detailing the experiments of Aldini, Galvani, Berlinghieri, Lind, Pfaff and Volta).

Sect. IV discourses on heterogeneous metals. During his experiments in this line, which were aided by his elder brother, chance led him to a very interesting discovery. He found that the coatings of the nerve and muscle being homogeneous, the contractions may be produced when the degree of excitability is extremely feeble, provided the coatings of this nature are united by exciting substances, among which there is a heterogeneous one, having one of its surfaces covered by a fluid in a state of vapour. This observation, which was originally made at the commencement of 1796, surprised Humboldt so much that he instantly communicated it to Sömmering, Blumenbach, Hertz and Goethe. He had not as yet found recorded in the published works on galvanism any experiment the result of which had the smallest analogy with his discovery; and it was not until after the publication of the works of Pfaff on animal electricity that he became acquainted with any one similar to his own. There were, however, some differences, as he proves by several passages cited from the above author.

Sect. V relates to the classification of active substances into exciters and conductors of the galvanic fluid.

Sect. VI treats of experiments on the comparative effects of animal and vegetable substances employed in the galvanic chain.

Sect. VII describes, in a tabular form, the conducting substances, and those by which the galvanic fluid is insulated. In the employment of very long conductors, it was not possible for Humboldt to remark any interval between the instant when the muscle contracts and the moment the contact of the conductor takes place, the muscle and nerve being from two hundred to three hundred feet distant from each other. This announces a celerity of twelve hundred feet per second. The effect would be the same, should the conductors even be from ten thousand to twenty thousand feet in length. Thus Haller, in his physiology, ascribes to the nervous fluid a swiftness sufficient to enable it to run over a space of nine thousand feet a second. The calculation of Sauvages is carried to thirty-two thousand four hundred feet in the same space of time; and what is still infinitely more surprising, its celerity is estimated by the author of the essays on the mechanism of the muscles at five hundred and seventy-six millions of feet (upward of one hundred thousand miles) in the above space of a second of time. It ought here to be noticed that the great differences in these calculations arise from the different kinds of experiments on which they are founded.

Sect. VIII proves that the nerve which is intended to excite contractions in a muscle should be organically united with it, and it deals with the effects of galvanism upon vegetables, aquatic worms, insects and fishes.

Sect. IX describes the effects of galvanism upon amphibious animals, referring to the observations of Nollet, Rosel, Haller, Spallanzani, P. Michaelis and Herembstads.

Sect. X treats of the all-important effects of galvanism upon man, and makes allusion to the experiments of Hunter, Pfaff, Fowler, Munro, Robison, Hecker, Carradori, Achard, Grapengieser, Schmuck, Ludwig, Creve, Webster and Volta. In speaking of the observations made by the last named upon the tongue, he observes that some idea of them had been given thirty years before, in Sulzer’s work entitled “The New Theory of Pleasures,” published in 1767; and that if, at the above period, the consideration of the superficial situation of the nerves of the tongue had led to the artificial discovery of a nerve, the important discovery of metallic irritation would have been made in the time of Haller, Franklin, Trembley, Camper, and Buffon. How great a progress would not this revelation have made if the above philosophers had transmitted to us, thirty years ago, the theory and experiments which we leave to our successors?

Volta having singled out the differences, in point of savour, which result from galvanic experiments on the tongue according to the nature and disposition of the coatings, Humboldt repeated these experiments and added to them several of his own, with a nearly similar result. His different trials, however, having failed to produce any contraction of the tongue, appear to have established the truth of the ancient assertion of Galen, confirmed by Scarpa, namely, that the nerve with which the tongue is supplied by the third branch of the fifth pair is exclusively devoted to the sense of tasting, and that the ninth pair are exclusively destined for the motion of the tongue. This has been evidently proved by the galvanic experiments on the nerve in question.

The termination, in the pituitous membrane, of the nerves belonging to the organ of smelling, which originate in the first pair and in the first two branches of the fifth, together with the observation of the innumerable phenomena of sympathy between the organs of sight and those of smell and taste, had led to a presumption that, by galvanizing the nostrils, the smell would be affected. This supposition has not, however, been confirmed by any experiment.

The eleventh chapter of Wilkinson’s work contains the analysis of the report drawn up by Mr. J. N. Hallé in behalf of the commission appointed by the French National Institute. This commission, which was organized to look into (examiner et vérifier) the different galvanic experiments which had been made and to ascertain their effects and results, was composed of such distinguished French physiologists as Coulomb, Fourcroy, Vauquelin, Charles, Sabathier, Hallé, Pelletan and Guyton de Morveau, who were afterward joined by both Humboldt and the celebrated Prof. Venturi, of Modena.

Humboldt’s observations respecting the application of galvanism to medicine are embodied in his well-known letter to M. Loder, inserted in “La Bibliothèque Germanique,” Vol. IV, Messidor, An. VIII. p. 301, and are likewise detailed by Wilkinson (Chap. XIII) where references are made, more particularly, to the experiments of Hufeland, Behrends, Creve, Hymly, Pfaff and Anschell.

Between the years 1799 and 1804 Von Humboldt made observations upon the magnetic intensity of the earth, of which an account will be found in Vol. XV of the Annalen der Physik. These were made upon the American Continent during the course of his well-known journey, the equal of which latter, says Petersen, has not been seen since the days when Alexander the Great fitted out an extensive scientific expedition for Aristotle.

Humboldt’s observations in the same line were continued for many years, notably between 1805 and 1806, in company with Gay-Lussac during a tour which they made together through France, Switzerland, Italy and Germany, as related in the first volume of the Mémoires de la Société d’Arcueil.

Some idea can be formed of the extent of Humboldt’s share in the magnetical labours of the first half of the century by perusing the last chapters of his “Cosmos” and the third volume of his “Relation Historique.” At p. 615 of the last-named work, he himself says: “The observations on the variation of terrestrial magnetism, to which I have devoted myself for thirty-two years, by means of instruments which admit of comparison with one another, in America, Europe and Asia, embrace an area extending over 188 degrees of longitude from the frontier of Chinese Dzoungarie to the West of the South Sea, bathing the coasts of Mexico and Peru, and reaching from 60 degrees North latitude to 12 degrees South latitude. I regard the discovery of the law of the decrement of magnetic force from the pole to the equator as the most important result of my American voyage.”

Humboldt was the first who made especial observations of those irregular perturbations to which he applied the name of “magnetic-storms,” and the effects of which he originally observed at Berlin in 1806. These are treated of in his “Cosmos,” London, 1858, Vol. V. pp. 135, etc., wherein he states that, when the ordinary horary movement of the needle is interrupted by a magnetic-storm, the perturbation manifests itself often simultaneously, in the strictest sense of the word, over land and sea, covering hundreds and thousands of miles, or propagates itself gradually, in short intervals of time, in every direction over the earth’s surface. In this same work (“Cosmos,” Sabine’s translation, Vol. I. p. 180), he contributes a graphic description of the concurrent and successive phases of a complete aurora borealis, reference to which is made by Noad (“Manual,” etc., pp. 228, 229, 235), who, likewise, gives (pp. 612–615) an account of the establishment of magnetic stations at different points, for simultaneous observations, upon a plan originally laid out by Humboldt.

As early as 1806, this great naturalist had published at Erfurt his “Inquiry Concerning Electrical Fishes.” While at Naples with Gay-Lussac, during the previous year, they had examined the properties of the torpedo, and had observed more particularly that the animal must be irritated previous to the shock, preceding which latter a convulsive movement of the pectoral fins is noticeable, and that electrical action is prevented by the least injury done to the brain of the fish; also, that a person accustomed to electrical discharges could with difficulty support the shock of a vigorous torpedo only fourteen inches long; that the discharge can be felt with a single finger placed upon the electrical organs, and that an insulated person will not receive the shock if the fish is touched with a key or other conducting body (Phil. Mag., Vol. XXII. p. 356; Annales de Chimie, No. 166; “Encycl. Brit.,” 1855, Vol. VIII. p. 573). Humboldt’s account of the mode of capturing gymnoti is detailed at pp. 575, 576 of the last-named work, as well as at pp. 472–474 of Noad’s “Manual of Electricity,” London, 1859.

At request of the King of Prussia, Humboldt returned from Paris to his native city in 1827, and it was during the winter of 1827–1828 that he began in Berlin his lectures on “Cosmos, or Physical Universe.” This is the title of his chief work, which has universally been recognized one of the greatest productions ever published, and one which Ritter pronounced as being the culminating point both in the history of science and in the annals of civilization.

REFERENCES.--Klenke, “Alex. Von Humboldt, ein biographisches Denkmal,” 1851: “Alex. Von Humboldt ... von Wittwer,” Leipzig, 1861; “Life of Alex. Von Humboldt,” translated by J. and C. Lassell, 2 Vols., London, 1873; “Meyer’s Konversations-Lexikon,” Leipzig und Wien, 1895, Vol. IX. pp. 44–47; Delambre’s eulogium on Humboldt will be found at p. 15, Vol. XV of “Edinburgh Review”; Gren’s “Neues Journal der Physik,” Vol. IV; Annales de Chimie, Vol. XXII; An. Chim. et Physique, Vol. XI; Poggendorff’s “Annalen,” Vols. XV, XXXVII; “Société Philomathique,” Tome I. p. 92; “Opus. Scelti,” XXI. p. 126; Knight’s “Mech. Dict.,” Vol. II. p. 1874; Phil. Mag., Vol. VI (1800), pp. 246, 250; “Cat. of Sc. Papers of Roy. Soc.,” Vol. III. pp. 462–467; Vol. VI. p. 692; Vol. VII. pp. 1035–1036; Sc. Am. Supp., No. 457, pp. 7301, 7302; Noad, “Manual,” pp. 425, 528, 529, 612; Harris, “Rudim. Magn.,” Part III. p. 103; Walker, “Ter. and Cos. Magn.,” 1866, p. 81; Humboldt, “Aphorismi ex doctrina ...” 1793; “Voyage, etc., dans les années, 1799–1804”; “Report of Seventh Meeting of British Association,” Vol. VI, London, 1838, pp. 1, 5 and 7, and the remainder of Major Sabine’s able article upon “Magnetic Intensity,” in the same volume; “Report of the Meeting of the French Academy of Sciences” of May 21, 1849, for extract of a letter from Emile H. Du Bois-Reymond, sent by Humboldt, and treating of the Electricity of the Human Frame (“L’Institut,” Mai 23, 1849); S. H. Christie and Sir G. B. Airy, “Report upon a Letter ...” London, 1836; C. H. Pfaff, “Mém. sur les expér. de Humboldt ...” 1799; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. pp. 168, 1580–1581.

=A.D. 1800.=--William Nicholson, editor of the journal bearing his name, as well as an able chemist, and Sir Anthony (then Mr.) Carlisle, an English surgeon, while carrying on a series of chemical experiments, discover that, by means of the voltaic pile, water is decomposed into its constituents of oxygen and hydrogen. Their pile consisted of seventeen silver half-crown pieces alternated with equal discs of copper and cloth soaked in a weak solution of ordinary salt, and, having used a little water to make good the contact of the conducting wire with a plate to which the electricity was to be transmitted, Carlisle observed that gas was being set free in the water, while Nicholson recognized the odour of hydrogen proceeding from it. The better to observe this result they afterward (May 2, 1800) employed a small glass tube, which, after being filled with water, was stopped at both ends with corks through which passed two brass wires extending a little distance into the water. When platinum wires were used, gas bubbles appeared from both wires, and the two gases, hydrogen from the negative and oxygen from the positive end, were found to be nearly in the proportion to constitute water. (See account of above in Pepper’s “Electricity,” p. 312, as well as at pp. 193 and 194 of Fahie’s “History of Telegraphy to 1837,” and at pp. 339 and 340 of Vol. I of Lardner’s “Lectures.”)

During the year 1781 William Nicholson had published the first edition of “An Introduction to Natural Philosophy.” In the second section of the third book of the latter work he treats of magnetism, the methods of communicating it, and the variation of the compass. The loadstone, he says, “is a ponderous ore of iron, usually of a dirty black colour and hard enough to emit sparks with steel. It is found in most parts of the world, and possesses a natural magnetism acquired most probably from its situation or position with respect to the earth.” In the third section of the same third book he discourses upon electrical matter, electrical jars, electrical instruments, and devotes much space to the explanation of experiments and facts touching natural and atmospheric electricity, balls of fire, of the ignis fatuus, or will-with-the-wisp, of waterspouts, earthquakes, etc., alluding to most of the then well-known observations thereon recorded by different scientists.

To Nicholson is due the invention of a revolving doubler, an improvement upon that of Abraham Bennet, which is described and illustrated in the “Encyclopædia Britannica,” as well as in No. 647, p. 10327, of the Sci. Am. Supplement (Read at A.D. 1794, also Phil. Trans., Vol. LXXVIII. p. 1, for M. Cavallo’s remarks upon the defects in Bennet’s doubler).

The above-named discovery of Nicholson and Carlisle, which, Mr. Davy says (Phil. Trans. for 1826, p. 386) was the true origin of all that had been previously done in electro-chemical science, together with Hisinger and Berzelius’ decomposition of salts, and the successful decomposition of ammonia, nitric acid, etc., made by the distinguished English chemical philosopher, Dr. William Henry (Nicholson’s Journal, Vol. IV. pp. 30, 209, 223 and 245; “Encyclopædia Metropolitana,” Vol. IV. pp. 221 and 611; Hutton’s abridgment of Phil. Trans., Vol. X. pp. 505, 599), as well as Davy’s decomposition of the earths and alkalies, creates at the commencement of another century, as we have already observed, an entirely new epoch in the history of chemistry.

REFERENCES.--Nicholson’s letter to the Royal Society, read June 5, 1788, entitled “A description of an instrument which, by the turning of a winch, produces the two states of electricity without friction or communication with the earth” (influence or induction machine!); Nicholson’s Journal, 1800, Vol. IV. p. 179; Despretz, “Physique,” 1827, p. 432; Mechanics’ Magazine, Nov. 9, 1839; biography in “English Cyclopedia,” Vol. II. p. 82; Tomlinson, “Cyclopedia of Arts,” etc., 1862, Vol. I. p. 566; “Memoir of Joseph Henry,” 1880, p. 78; Highton, “The Electric Telegraph,” p. 28; Noad, “Manual,” p. 353; “Encycl. Brit.,” 1855, Vol. XXI. p. 628; Phil. Trans., Vol. LXXIX. p. 265; Philosophical Magazine, Vol. VII. p. 337, and XLV. p. 396; C. H. Wilkinson, “Elements of Galvanism,” 1804, Vol. II. pp. 21, 22, 46, 68, 375, etc.; “Bibl. Brit.,” Vol. XIX. p. 274; “Sciences et Arts,” Part I. p. 274, and Part II. p. 339, for Volta’s answer to Nicholson. For various treatises on, and methods of, effecting the decomposition of water, consult Adam W. Von Hauch (Mons’ Jour. de Chimie, Vol. I. p. 109); G. Carradori (Journal de Physique, An. XII. p. 20, “Nuova Scel. d’Op.,” quarto, Vol. I. p. 29, Paris and Milan, 1804); W. Wilson (Phil. Mag., Vol. XXII. p. 260); Cioni e Petrini (Brugnatelli’s An. di Chim., Vol. II. p. 322, 1805); M. Van Marum’s letter to Nauche (Jour. du Galvan., Eleventh Book, p. 187; Gilb. Ann., XI. p. 220); J. C. I. A. Creve, as at Ronalds’ “Catalogue,” p. 119; “Bibl. Britan.,” An. VIII. vol. xv. p. 23 and An. IX. vol. xvi. p. 23; J. C. Cuthbertson (Phil. Mag., Vol. XXIV. p. 170, 1806); Jos. Mollet’s Memoirs published at Aix and Lyons, 1821, 1823, as well as in the Reports of the Lyons Academy, 1823, 1825, and in the Comptes Rendus for 1823; Mr. Leeson (Sturgeon’s Annals, Vol. IV. p. 238, 1839; Robert Hare, Trans. Am. Phil. Soc., N.S., Vol. VI. p. 339; L. Palmieri and P. Linari-Santi, “Telluro-Elettricismo,” 1844; M. Merget’s theses, read before the Paris Academy, Aug. 30, 1849; A. Connel, Phil. Mag., 4th Ser., for June 1854, p. 426); Dr. Edward Ash, “On the action of Metals ... upon water,” in letter to Humboldt, April 10, 1796.

=A.D. 1800.=--Grout (Jonathan, Jr.), of Belchertown, Mass., takes out, October 24, the first telegraph patent in the United States. It was for a contrivance which he operated between Martha’s Vineyard and Boston, about ninety miles’ distance, from hilltop to hilltop, and which was sighted by telescopes (“Telegraph in America,” J. D. Reid, 1887, p. 5; also “Growth of Industrial Art,” Washington, 1888, p. 55).

=A.D. 1800.=--Cruikshanks (William), of Woolwich, England, confirms Nicholson and Carlisle’s experiments, and, in his further prosecution of them, employs a pile consisting of from forty to a hundred pairs of zinc and silver plates, as well as a tube holding silver terminals or electrodes, in place of the platinum electrodes, which they were first to make use of.

He discovers that hydrogen is always evolved from the silver or copper end of the voltaic pile and oxygen from the other; that, under like circumstances, metals can be “completely revived” from their solutions; that pure oxygen is freed when a wire of non-oxidable metal, like gold, is connected with the zinc plate, and that fluids that contain no oxygen cannot transmit the voltaic current. These results were verified by Lieut. Col. Henry Haldane, whose many observations upon the series of metals best suited to the production of voltaic electricity and their respective powers in connection therewith are related at pp. 242 and 313, Vol. IV of Nicholson’s Journal for Sept. and Oct. 1800.

Cruikshanks was also the first to discover, in 1800, that when passing the electric current through water tinged with lithmus, the wire connected with the zinc end of the pile imparted a red tinge to the fluid contiguous to it, and that by using water coloured with Brazil wood, the wire connected with the silver end of the pile produced a deeper shade of colour in the surrounding fluid, whence it appeared that an acid was formed in the former case, and an alkali in the latter. Fahie, who thus mentions the fact, justly remarks that upon this discovery are dependent the electro-chemical telegraphs proposed by Bakewell, Caselli, Bonelli, D’Arlincourt, Sawyer and others.

Cruikshanks is the inventor of the galvanic trough, an improvement upon the voltaic pile, made by soldering together rectangular plates of zinc and copper, and so arranging them horizontally, in a box of baked wood coated with an insulating substance, as to allow of open spaces which can be filled with a solution of salt and water or with diluted acid, to take the place of the wet plates of cloth, paper or pasteboard. Cruikshanks’ plan was adopted in the construction of the powerful battery of 600 pairs, which Napoleon Bonaparte presented to the Ecole Polytechnique and upon which Gay-Lussac and Thénard made their important experiments during the year 1808. As Noad remarks, it is a very convenient form when sulphate of copper is used, for Dr. Fyfe has shown (Phil. Mag., Vol. XI. p. 145) that this exciting agent increases the electro-chemical intensity of the electric current as compared with that evolved by dilute sulphuric acid in the proportion of 72 to 16.

Both the above and Volta’s form of battery were much improved upon by Dr. William Babington (1756–1833), who united the pairs of zinc and copper plates by soldering them at one point, and by attaching them to a strip of wood in such a manner as to allow of the entire line being immersed at will into an earthenware or wooden trough having a corresponding number of cells or partitions. The extraordinarily strong voltaic battery, constructed in 1808 for the Royal Institution of London, by Mr. Eastwick under the direction of Sir Humphry Davy and of John George Children, was built upon this plan. It consisted of 200 separate parts, each part being composed of ten double plates, in all 2000 double plates of zinc and copper with a total surface of 128,000 square inches, and the charge which William H. Pepys was accustomed to give it consisted of a mixture of 1168 parts of water, 108 parts nitrous acid, and 25 parts sulphuric acid.

REFERENCES.--Wilkinson, “Elements of Galvanism,” 1804, Vol. II. pp. 52–63, 96–99; Pepper, “Electricity,” 1809, pp. 313–315; Noad, “Manual,” pp. 263, 264; Tomlinson, “Cyclopædia of Arts,” Vol. I. p. 566; Napier, “Electro-Metallurgy,” 1853, pp. 27, 28; Nicholson’s Journal, Vol. IV. pp. 187, 254, 261 and 511; Sturgeon’s Annals, Vol. IX. p. 309; Cruikshanks, “Some Experiments and Observations on Galvanic Electricity,” July 1800; also “Additional Remarks on Galvanic Electricity,” September 1800.

=A.D. 1801.=--Davy (Humphry), a very eminent English chemical philosopher, whose early studies had been greatly influenced both by Dr. John Tonkin, of Penzance, and by Gregory Watt, son of the celebrated inventor, James Watt, as well as by Mr. Davies Giddy Gilbert, who brought him to the notice of the English Royal Institution, delivers before the latter body, on the 25th of April 1801, his first lecture, wherein he traces the history of galvanism, and describes the different methods of “accumulating” it.

His first communication to the Royal Society was made in June of the same year, and is entitled, “An Account of Some Galvanic Combinations Formed by the Arrangement of Single Metallic Plates and Fluids, Analogous to the New Galvanic Apparatus of Volta.” As his able biographer, Prof. T. James Stewart Traill, M.D., of Edinburgh, remarks, this paper is the first of that series of electro-chemical investigations which have immortalized his name. In all hitherto constructed piles, the series had consisted of not less than two metals, or of one plate of metal, another of charcoal, and some interposed fluid. He showed in this paper that the usual galvanic phenomena might be energetically exhibited by a single metallic plate and two strata of different fluids, or that a battery might be constructed of one metal and two fluids, provided one of the fluids was capable of causing oxidation on one of the surfaces of the metal (“Bakerian Lectures,” London, 1840, pp. 32, etc., and Phil. Trans., Vol. XCI. p. 297).

On the 20th of November 1806 was read before the Royal Society Davy’s first Bakerian lecture, “On Some Chemical Agencies of Electricity.” This essay was universally regarded as one of the most valuable contributions thus far made to chemistry, and obtained for Davy the prize founded by Napoleon when First Consul, to be awarded by the French Institute, “à celui, qui par ses expériences et ses découvertes, fera faire a l’électricité et au galvanisme un pas comparable à celui qu’ont fait faire à ces sciences Franklin et Volta” (“Bakerian Lectures,” 1840, p. 56, and notes at p. 349, Vol. I of Dr. Lardner’s “Lectures,” etc., 1859).

Of the French Institute Davy became a member in 1817. Regarding the above-named important paper, given in full at pp. 1–56, of the volume of “Bakerian Lectures,” already referred to, Davy says (Phil. Trans. for 1826, p. 389): “Referring to my experiments of 1800, 1801 and 1802, and to a number of new facts, which showed that inflammable substances and oxygen, alkalies and acids, and oxidable and noble metals, were in electrical relations of positive and negative, I drew the conclusion that the combinations and decompositions by electricity were referable to the law of electrical attractions and repulsions,” and advanced the hypothesis “that chemical and electrical attractions were produced by the same cause, acting in the one case on particles; in the other on masses; ... and that the same property, under different modifications, was the cause of all the phenomena exhibited by different voltaic combinations” (Vol. I. pp. 678–684 of Dr. Thomas Young’s “Course of Lectures,” London, 1807, on “Electricity in Motion,” also Dr. Henry M. Noad’s “Manual,” London, 1859, pp. 362–365).

The second Bakerian lecture, “On some new phenomena of chemical changes produced by electricity, particularly the decomposition of the fixed alkalies, and the exhibition of the new substances which constitute their bases; and on the general nature of alkaline bodies,” was read Nov. 19, 1807. In this he gives an account of the most brilliant of all his discoveries (made during the previous month), proving that the so-called fixed alkalies are merely combinations of oxygen with metals. It has been stated by Dr. John Ayrton Paris that since the days of Newton no such happy and successful instance of philosophical induction has ever been afforded as that by which Davy reached the above-named results (Phil. Trans. for 1808, Vol. XCVIII. pp. 1–44). Davy’s observations were fully confirmed by Gay-Lussac, Thénard, Berzelius and Pontin (Annales de Chimie, Vol. LXXII. p. 193; Vol. LXXV. pp. 256–291; Bibl. Brit. for June 1809, p. 122). Although Davy was less successful in his attempt to decompose the proper earths, he proved that they consist of bases united to oxygen. It was reserved for Friedrich Wöhler, Berzelius and Bussy to exhibit the bases by themselves, and to show that all, excepting silica, are metallic, and capable of uniting with iron.

It is said that the original 500-plate batteries of the Royal Institution were so worn in the course of Davy’s experiments as to be almost unserviceable, and that he suggested to the managers the propriety of starting a subscription for the purchase of a large galvanic battery. This being acted upon during the month of July 1808, he was placed in possession of the battery already alluded to in the Cruikshanks article (A.D. 1800), and which was the most powerful constructed up to that time. “With this battery Davy did not reach any new results of importance; but he was enabled to demonstrate the galvanic phenomena upon a more brilliant scale. Nor was the increased power necessary to carry on successfully the experiments on the decomposition of the alkalies and the earths as was apparently believed by many of those historians of science ... who attributed the author’s brilliant success in electro-chemical research to his supposed extraordinary means, the enormous voltaic batteries of the Royal Institution.” In this connection, the terse notes appearing at foot of pp. 62, 63, 106, 107 of the 1840 edition of the “Bakerian Lectures” will prove interesting reading.

It was with the afore-named galvanic combination that Davy openly made--in 1809–1810, and not in 1813, as has been frequently stated--the first display of the continuous electric arc (John Davy, “Memoirs of the Life of Sir Humphry Davy,” p. 446).

“When the cells of this battery were filled with sixty parts of water mixed with one part of nitric acid and one part of sulphuric acid,” he says, “they afforded a series of brilliant and impressive effects. When pieces of charcoal about an inch long and one-sixth of an inch in diameter were brought near each other (within the thirtieth or fortieth part of an inch), a bright spark was produced, and more than half the volume of the charcoal became ignited to whiteness, and by withdrawing the points from each other a constant discharge took place through the heated air, in a space equal at least to four inches, producing a most brilliant ascending arch of light, broad and conical in form in the middle. When any substance was introduced into this arch, it instantly became ignited; platina melted as readily in it as wax in the flame of a common candle; quartz, the sapphire, magnesia, lime, all entered into fusion; fragments of diamond, and points of charcoal and plumbago, rapidly disappeared, and seemed to evaporate in it, even when the connection was made in a receiver exhausted by the air pump; but there was no evidence of their having previously undergone fusion” (“Elements of Chemical Philosophy,” 1812, p. 154).

Dr. Paris says that Davy had already produced the spark upon a small scale as far back as 1800 (Nicholson’s Journal, Vol. III, quarto, p. 150), and we learn, through an article published upon the early experiments with the electric light, the names of others who had likewise noticed the arc at about the same period, while Quetelet informs us that M. Curtet is reported to have observed the light between carbon points during the year 1802 (Curtet’s letter to J. B. Van Mons in the latter’s Journal de Chimie, No. VI. p. 272, and in Journal de Physique, An. XI. p. 54). The article referred to is as follows:

“Dr. S. P. Thompson has given the following interesting details in regard to this subject: In looking over an old volume of the Journal de Paris, I found, under date of the Twenty-second Ventose, An. X (March 12, 1802), this passage, which evidently refers to an exhibition of the electric arc: ‘Citizen (E. G.) Robertson, the inventor of the phantasmagoria (magic lantern), is at present performing some interesting experiments that must doubtless advance our knowledge concerning galvanism. He has just mounted metallic piles to the number of 2500 zinc plates and as many of rosette copper. We shall forthwith speak of his results, as well as of a new experiment that he performed yesterday with two glowing carbons. The first having been placed at the base of a column of 120 zinc and silver elements, and the second communicating with the apex of the pile, they gave at the moment they were united a brilliant spark of an extreme whiteness that was seen by the entire society. Citizen Robertson will repeat the experiment on the 25th.’”

The date generally given for this discovery by Humphry Davy is 1809, but earlier accounts of his experiments are found in Cuthbertson’s “Electricity” (1807), and in several other works.

In the Phil. Mag., Vol. IX. p. 219, under date of Feb. 1, 1801, in a memoir by Dr. H. Moyes, of Edinburgh, relative to experiments made with the pile, we find the following passage: “When the column in question had reached the height of its power, its sparks were seen by daylight, even when they were made to jump with a piece of carbon held in the hand.” In the same volume of the Phil. Mag., and immediately following Dr. Moyes’ letter to Dr. Garthshore, on experiments with the voltaic pile, will be found an account of similar investigations made in Germany, and communicated by Dr. Frulander, of Berlin.

In the “Journal of the Royal Institution” (1802), Vol. I. p. 106, Davy describes a few experiments made with the pile, and says: “When instead of metals, pieces of well-calcined carbon were employed, the spark was still larger and of a clear white.” On p. 214 he describes and figures an apparatus for taking the galvano-electric spark into fluid and aeriform substances. This apparatus consisted of a glass tube open at the top, and having at the side another tube through which passed a wire that terminated in a carbon. Another wire, likewise terminating in carbon, traversed the bottom, and was cemented in a vertical position.

But all these observations are subsequent to a letter printed in “Nicholson’s Journal” for October 1800, p. 150, entitled “Additional experiments on Galvanic Electricity in a letter to Mr. Nicholson.” The letter is dated Dowry Square, Hotwells, Sept. 22, 1800, and is signed by Humphry Davy, who at this epoch was assistant to Dr. Beddoes at the Philosophical (Pneumatic) Institution of Bristol. It begins thus:

“Sir: The first experimenters in animal electricity remarked the property that well calcined carbon has of conducting ordinary galvanic action. I have found that this substance possesses the same properties as metallic bodies for the production of the spark when it is used for establishing a communication between the extremities of Signor Volta’s pile.”

Among the papers read by Davy before the Royal Society between June 30, 1808, and Feb. 13, 1814, are the following: “Electro-chemical researches on the decomposition of the earths, with observations on the metals obtained from the alkaline earths, and on the amalgam procured from ammonia”; “An account of some new analytical researches on the nature of certain bodies,” etc., and the Bakerian lecture “On some new electro-chemical researches, on various objects, particularly the metallic bodies from the alkalies and earths, and on some combinations of hydrogen”; “Elements of chemical philosophy, detailing experiments on electricity in vegetation.”

In alluding to the important subjects covered by him during the above-named period, his brother and biographer, John Davy, M.D., F.R.S., says: “I shall not attempt an analysis of these papers; I shall give merely a sketch of the most important facts and discoveries which they contain, referring the chemical reader to the original for full satisfaction. After the extraction of metallic bases from the fixed alkalies, analogies of the strongest kind indicated that the alkaline earths are similarly constituted; and he succeeded in proving this in a satisfactory manner. But, owing to various circumstances of peculiar properties, he was not able on his first attempts to obtain the metals of those earths in a tolerably pure and insulated state for the purpose of examination. On his return to the laboratory after his illness, this was one of the first undertakings. He accomplished it to a certain extent by uniting a process of Messrs. Berzelius and Pontin, who were then engaged in the same enquiry, with one of his own. By negatively electrifying the earths, slightly moistened, and mixed with red oxide of mercury, in contact with a globule of mercury, he obtained amalgams of their metallic bases; and, by distillation, with peculiar precautions, he expelled the greater part of the mercury. Even now, in consequence of the very minute quantities of the bases which he procured, and their very powerful attraction for oxygen, he was only able to ascertain a few of their properties in a hasty manner. They were of silvery lustre, solid at ordinary temperatures, fixed at a red heat, and heavier than water. At a high temperature they abstracted oxygen from the glass, and, at ordinary temperatures, from the atmosphere and water, the latter of which in consequence they decomposed. The names he proposed for them, and by which they have since been called, were barium, strontium, calcium and magnium, which latter he afterwards altered to magnesium....”

The reviewer of Davy, in the columns of the “Chemical News,” writing in 1879, states that his papers on numerous subjects flowed into the Royal Society’s archives in an uninterrupted stream, and it may be said, without exaggeration, that his work, especially during the six years from 1806 to 1812, did more for chemistry than the 60 which followed them.

Between the last-named dates, Davy was asked by the Dublin Society to give a course of lectures on electro-chemical science, which he delivered Nov. 8–29, 1810. Trinity College afterward conferred on him the degree of LL.D., and he was knighted by the Prince Regent one day before resigning from the Royal Institution, wherein he gave his farewell address on April 9, 1812.

In 1813, accompanied by his bride and Mr. Faraday (his “assistant in experiments and in writing”), Davy made his first trip to the Continent, where he met Ampère, Humboldt, Gay-Lussac, Vauquelin, Cuvier, Laplace and other distinguished scientists, and where he carried on many experiments, of which the results were duly communicated to the Royal Society, as were also the observations made by him up to the time of the completion of his second trip in 1820.

Besides the Rumford medal conferred on him in 1816, he received a baronetcy two years later, and was given, in 1827, the medal of the Royal Society, the presidential chair of which he occupied for seven consecutive years.

One of the four memoirs produced by Davy in 1818–1829 treats of electro-magnetism. In 1820, Davy, Arago and Seebeck independently discovered the magnetizing power of the electric current on steel and iron needles or filings. In Davy’s experiments, it is said, the filings adhered to the wire connecting the poles of a voltaic apparatus, consisting of a hundred pairs of plates of four inches, in such considerable quantities as to form a mass around it ten or twelve times the thickness of the wire (Phil. Trans. for 1821, p. 9; Annales de Chimie et de Physique, Vol. XV. p. 93).

Davy was actively engaged during 1821–1822 in experiments on electro-magnetism and on electricity in vacuo, reaching the conclusion, in the last-named channel, that electric light as well as electrical attractions and repulsions are observable in the most perfect vacuum obtainable. This is readily demonstrated with either the apparatus employed by Tyndall in his Lecture VIII, “On the analogies of light, heat and sound,” or with the apparatus used by Davy and illustrated at Plate CCXXIII of the “Encyclopædia Britannica,” eighth edition. From the numerous experiments and observations recorded in the last-named work the following are extracted:

“A spark capable of passing through only half an inch in common air will pass through six inches of the Torricellian vacuum.... When the minutest quantity of rare air was introduced into the mercurial vacuum, the colour of the electric light changed from bright green to sea green, and by increasing the quantity, to blue and purple. At a low temperature the vacuum became a much better conductor. A vacuum above fused tin exhibited nearly the same phenomena. At temperatures below zero the light was yellow and of the palest phosphorescent kind, just visible in great darkness, and not increased by heat. When the vacuum was formed by pure olive oil and by chloride of antimony, the electric light through the vapour of the chloride was more brilliant than that through the vapour of the oil; and in the last it was more brilliant than in the vapour of mercury at common temperatures. The light was of a pure white with the chloride, and of a red inclining to purple in the oil.... In carbonic acid gas the light of the spark is white and brilliant, and in hydrogen gas it is red and faint. When the sparks are made to pass through balls of wood or ivory they are of a crimson colour. They are yellow when taken over powdered charcoal, green over the surface of silvered leather, and purple from imperfect conductors.”

Davy’s Bakerian lecture for 1826 was entitled “On the relation of electrical and chemical changes.” Two years previous to its reading he had communicated to the English Government his discovery of what he erroneously considered a remedy against the rapid deterioration of copper sheathing for ships. His plan consisted in altering the electrical condition of the copper by adding plates of zinc or iron (called “protectors”), but the bottoms of the vessels became so foul through the deposition of calcareous matter and the adhesion of large balani and lepades, etc., to the copper, that the attempt had to be abandoned (A. Bobierre, “Thèse ... pour doubler les navires,” Nantes, 1858). It was in the same year (1824) that Davy made an important journey through Sweden, Norway, Denmark, Holstein, and Hanover, during which he met Oersted, Berzelius, Gauss, Olbers, Schumacher and other savants.

His last communication to the Royal Society, “Remarks on the Electricity of the Torpedo,” was sent from Rome in 1828, one year before his death, and embodies the result of many observations made while on the Continent, more especially during the years 1814–1815. The investigations in this line which, owing to continued ill health, he was unable to carry on, were completed by his brother, Dr. John Davy, who established the following points of difference between the phenomena of the torpedo and those of other kinds of electricity:

“Compared with voltaic electricity, its effect on the multiplier is feeble: its power of decomposing water and metallic solutions is inconsiderable; but its power of giving a shock is great, and so also is its power of magnetizing iron. Compared with common electricity, it has a power of affecting the multiplier, which, under ordinary circumstances, common electricity does not exhibit; its chemical effects are more distinct; its power of magnetizing iron and giving a shock appears very similar; its power of passing through air is infinitely less as is also (if it possess it at all) the power of producing heat and light.”

Davy likewise made noteworthy observations concerning the pyro-electricity of the tourmaline, confirming previous investigations in the same line, and asserting that “when the stone is of considerable size, flashes of light may be seen along its surface” (“Elements of Chemical Philosophy,” Vol. I. p. 130), a curious fact which Sir David Brewster says he does not believe has ever been verified by any subsequent observer.

It is not within the scope of this “Bibliographical History” to describe Davy’s other notable papers relative to the miner’s safety lamp, etc., but reference should be made here to his first scientific memoir, “On heat, light and the combination of light” (Sir H. Davy’s works, Vol. II) of which copious extracts are given by Prof. John Tyndall in the appendix to his third lecture on “Heat considered as a mode of motion.”

As regards the caloric theory, which had deservedly been engaging the attention of so many scientists, it is, however, thought best to quote here from Deschanel’s article on thermo-dynamics: “Strange to say, this theory survived the many exposures of its weakness and the, if possible, still more conclusive experiment of Sir Humphry Davy, who showed that two pieces of ice, when rubbed together, were converted into water, a change which involves not the evolution but the absorption of latent heat, and which cannot be explained by diminution of thermal capacity, since the specific heat of water is much greater than that of ice. Davy, like Rumford, maintained that heat consisted in motion, and the same view was maintained by Dr. Thomas Young; but the doctrine of caloric nevertheless continued to be generally adopted until about the year 1840, since which time the experiments of Joule, the eloquent advocacy of Meyer, and the mathematical deductions of Thomson, Rankine and Clausius, have completely established the mechanical theory of heat, and built up an accurate science of thermo-dynamics.”

REFERENCES.--“The Life of Sir H. Davy,” by John Ayrton Paris, M.D., 1831, and by T. E. Thorpe, New York, 1896, also his life by Dr. John Davy, F.R.S., 1836; and his biography and articles “Chemistry” and “Voltaic Electricity” in the “Encyclopædia Britannica”; “Works of Sir Humphry Davy,” edited by John Davy, 1839–1840; “The Fragmentary Remains ... of Sir H. Davy,” 1858; “Dic. Tech. et Prat. d’Electricité” de Mr. Geo. Durant, Paris, 1887–1889; W. T. Brande, “Manual of Chemistry,” London, 1848, Vol. I. pp. xciii-cv, 213–224; C. H. Wilkinson, “Elements of Galvanism,” London, 1804, Vol. II. pp. 80–86, and Chap. XXVII; Thomas Thomson, “History of the Royal Society,” London, 1812, pp. 454–455; “Galvanism,” in Dr. Lardner’s Lectures; Noad’s “Lectures on Chemistry,” pp. 32–33; Bakewell’s “Elec. Sc.,” pp. 33–35; Daniel Davis, “Manual of Magnetism,” 1846–1852; Thomson, “History of Chemistry,” Vol. II. pp. 260–261; “Elem. of Exp. Chem.,” Wm. Henry, London, 1823, Vol. I. p. 192; “Elements of Chemical Philosophy,” p. 155; Thomas Thomson, M.D., London, 1830; “Outline of the Sciences of Heat and Electricity,” pp. 467, et. seq., 491–495, 533; De la Rive’s “Treatise on Electricity ...” Vol. II. pp. 282–283; “Encyclopedia Metropolitana,” Vol. IV (Galv.), pp. 176, 178, 222, and (Elec. Mag.) pp. 9 and 10; Gay-Lussac and Thénard, Phil. Mag., Vol. XXXII. p. 88, 1809; Jacquin, Phil. Mag., Vol. XXXVI. p. 73, 1810; M. Donovan, Phil. Mag., Vol. XXII. pp. 227, 245, 1811; M. Yatman, “A Letter ...” and Davy’s “Enquiries ...” London, 1811, 1814; W. Henry, “On Sir H. Davy and Dr. Wollaston,” London, 1830; Contessi G. Lelandri, “Ann. Reg. Lomb., Veneto,” 11, 78, 1832, and F. I. Roux, “Conservation des plaques ...” Paris, 1866; Nicholson’s Journal, 4to, Vol. IV. pp. 275, 337 and 394; and 8vo., Vol. I. p. 144, Vol. III. p. 135; Dredge, “Electric Illumination,” Vol. I. pp. 24, 25, 30; Phil. Mag., Vol. VII. p. 347, for experiments of Dr. Henry Moyes, also Vol. XI. pp. 302, 326; XXVIII. pp. 3, 104, 220; XXIX. p. 372; XXXI. p. 3; XXXII. pp. 1, 18–22, 101, 146, 193; XXXIII. p. 479; XXXV. p. 401; XXXVI. pp. 17, 85, 352, 404; XL. p. 145; LVIII. pp. 43, 406; LIX. p. 468; LX. p. 179; Phil. Mag. or Annals, Vols. I. pp. 31, 94, 190; VI. p. 81; X. pp. 214, 379, 426; Phil. Trans. for 1801, 1809, 1810, 1822; Sturgeon’s “Scientific Researches,” Bury, 1850, pp. 14–16, 23; Annales de Chimie, Vol. XV. p. 113; “Société Philomathique,” An. X. p. 111; Becquerel, Paris, 1850, Vol. I. pp. xi and 33 note; “Nuova Scelta d’Opusc.” Vol. II. pp. 190, 282; “Beiträge zur Erweiterung,” etc., Berlin, 1820; “Elemente d. Chemischen,” etc., Berlin, 1814; “Royal Society Catalogue of Scientific Papers,” London, 1868, Vol. II. pp. 171–175; “Biographie Générale,” Vol. XIII. p. 264; “Engineering,” London, Vol. LII. p. 759; “Abstracts of Papers ... Roy. Soc.,” London, 1832–1833, Vol. I. pp. 59, 247, 278, 313, 350; Vol. II. pp. 154, 159, 189, 213, 242, 281, 354; “Royal Society Catalogue of Scientific Papers,” Vol. II. pp. 175–180, and Vol. VI. p. 633 (likewise Vol. VII. pp. 494–495--for John Davy); “Bibliothèque Britannique,” Vol. XVII for 1801, pp. 237, 246; Vol. XXV, N.S. for 1824, p. 98; Vol. XXXIV, O.S. for 1807, p. 397 (the same as “Nicholson’s Journal,” for January 1807); Vol. XXXV. pp. 16, 141; “Edin. Phil. Journ.,” Vol. X. p. 185.

Of the afore-named references in the Phil. Magazine, Vol. XXXI, that at p. 3 relates to Davy’s new Eudiometer acting by the electric spark exactly in the same manner as that of Il Marchese de Brezé, described in the “Opuscoli.”

=A.D. 1801.=--Flinders (Matthew), a very able navigator and captain in the English merchant service, sails in the bark “Investigator” for the purpose of circumnavigating and exploring New Holland. During this memorable voyage he carefully observed the cause of errors in the variation of the magnetic needle as depending on the direction in azimuth of the ship’s head, having often noticed, as a writer in the English Quarterly Review expresses it (Vol. CXVIII. p. 343), that the direction of the compass needle frequently wandered from that which the known variation due to the geographical position of the ship assigned to it. To correct those disturbances he suggested placing aft of the compass a vertical bar of soft iron, whose upper end, having like magnetism as the imaginary mass in the ship’s head, would, in acting on the opposite pole of the compass needle, rectify its disturbances.

Flinders had, during the year 1795, made observations in the same line as those recorded by the astronomer Bayly, who had sailed with Captain Cook during his last two voyages, but it was not until his return from the unfortunate first voyage above alluded to that he properly recorded his investigations for the benefit of navigators.

REFERENCES.--“Encyclopædia Britannica,” 1856, Vol. X. p. 295, and article “Australia,” Vol. IV. pp. 253, 254; “English Cyclopædia” (Biography), Vol. II. pp. 933–935; Sci. Am. Supp., No. 534, p. 8526; William Walker, “The Magnetism of Ships,” London, 1833, pp. 21–23; “Abstracts of Papers of the _Phil. Trans._, 1800–1830,” p. 187; Phil. Trans. for 1805; John Farrar, “Elem. of Elect.,” 1826, p. 381; “Cat. Sc. Papers Royal Soc.,” Vol. I. p. 187.

=A.D. 1801.=--Gautherot (Nicholas), able French chemist (1753–1803), discovers that when a current has passed through two plates or wires of the same metal in dilute sulphuric acid, a secondary, reverse or polarization current is obtainable after disconnecting the battery. This was the first step in the storage of electricity and an account is given of it in the Philosophical Magazine, Vol. XXIV. pp. 185–186, which contains a report of the proceedings before the Galvani Society of Paris. Gautherot says that the results he obtained should become the source or basis of several other experiments, and concur more than any other to the discovery of the theory of this new branch of physics.

In this same year Gautherot observed the power of adhesion of the two wires in contact with the upper and lower ends of the pile, a report upon which appears at p. 209, Vol. XXXIX of the Annales de Chimie, while a full account of his observations on the subject forms the substance of a separate work printed in London during the year 1828.

The French physicist, C. J. Lehot, makes allusion to the last-named discovery in the following words, at p. 4 of his pamphlet entitled “Observations sur le Galvanisme et le Magnétisme”:

“It has long been known that the two wires which terminate a pile attract one another, and, after contact, adhere like two magnets. This attraction between the two wires, one of which receives, and the other loses, the galvanic fluid, differs essentially from electrical attraction, as Ritter observed, since it is not followed by a repulsion after contact, but continues as long as the chain is closed.”

J. J. Fahie, who also quotes this passage, says:

“The discovery in question seems to have been made independently, and at about the same time by Gautherot (Philosophical Magazine or Annals for 1828, Vol. IV. p. 458), by P. S. Laplace, and by J. B. Biot (Journal de Physique et de Chimie, for 1801, Vol. LIII. p. 266). The latter made the further very acute observation that, if the wires are attached to plates of metal, and these plates approached by their edges, they will attract one another; while if approached by their faces no action whatever takes place. For other interesting experiments of this kind see ‘Nicholson’s Journal’ for 1804, Vol. VII. p. 304.”

Previous to the aforesaid discoveries, on the 12th Brumaire, An. IX (Nov. 1800), Gautherot had published his refutation of Volta’s contact theory, through the Paris “Société Philotechnique,” and it is to be found recorded at p. 471, Vol. I of the “Mémoires des Sociétés Savantes et Littéraires de la République Française.”

Later on he devoted so much attention to galvanic researches that Messrs. A. F. de Fourcroy and L. N. Vauquelin made a special report upon the five important memoirs containing the results of his many observations to the French Institute on the 21st Fructidor.

The first memoir gives the whole theory and practice of the various kinds of conductors, and describes an apparatus devised by Gautherot to ascertain the conducting powers of different natural, solid, liquid and even gaseous bodies (Izarn, “Manuel du Galvanisme” 1804, pp. 56–60). He enters into full details as to the effects of the voltaic pile in many experiments made upon himself, and draws consequences which apparently disprove the identity of the electric and the galvanic fluids.

The second memoir treats of the galvanic properties of charcoal, and shows that it is a less perfect conductor than are metallic substances.

In the third memoir he makes known his discovery that charcoal and zinc form a galvanic apparatus which will produce shocks, the decomposition of water, etc. He observes “that in the decomposition of water, charcoal decomposes that fluid in the same way with non-oxydable metals; or, in other words, that when two pieces of charcoal are employed for this purpose, one of them disengages the hydrogen gas, and the other the oxygen ... when the portions of charcoal touch each other in the water, its decomposition is not stopped on that account, as happens when metallic substances are brought in contact under the same circumstances. Indeed, if to bring more immediately together, one of the pieces of charcoal be cut in a furcated shape, this does not become an obstacle to the decomposition of the water.”

The fourth memoir treats further of different kinds of conductors, and of various methods of constructing galvanic columns.

In the fifth and last memoir, Gautherot relates his important discovery that an effective galvanic apparatus can be made without metals. He constructed one of forty layers of charcoal and plumbago, which communicated a strong and pungent taste, accompanied by the galvanic flash of light, and which finally produced the decomposition of water, the charcoal side disengaging the hydrogen gas (Izarn, “Manuel du Galvanisme,” 1804, p. 177).

During the month of March 1803, he read before the “Institut National” a memoir entitled “Recherches,” etc. (researches upon the causes which develop electricity in the galvanic apparatus). This appeared in the Journal de Physique, Vol. LVI. p. 429.

REFERENCES.--“Biographie Générale,” Vol. XIX. p. 694; Larousse, “Dict. Univ.,” Vol. VIII. p. 1089; Izarn, Giuseppe (Joseph) “Manuel du Galvanisme,” Paris, An. XII. 1804, s. 6, pp. 95, 250–254: Mém. des Soc. Savantes, etc., Vol. I. pp. 164, 168; P. Sue, aîné, “Hist. du Galvanisme,” Paris, An. X, 1802, Vol. II. pp. 191, 196–203, 213, 214, 316; Alglave et Boulard, Lumière Electrique, Paris, 1882, p. 219; Poggendorff, Vol. I. p. 857; “Extrait d’une lettre de Brugnatelli,” etc., Bruxelles, 1802 (Van Mons, Journal de Chimie, Vol. II. p. 216).

=A.D. 1801.=--Robertson (Etienne Gaspard), a very capable French experimentalist and one of the founders of the Paris Galvani Society, who has already been alluded to in the article relating to Sir Humphry Davy, writes a memoir, “Expériences nouvelles sur le fluide galvanique,” which was read before the Institute on the 11th Fructidor, An. VIII, and which appeared in the Annales de Chimie (Vol. XXXVII. p. 132), as well as in the “Mémoires Récréatifs, Scientifiques,” etc., published in Paris during 1840, three years after Robertson’s death.

Robertson states that as he was delivering a lecture on the 9th Vendémaire, An. IX, during which he alluded to differences which he found to exist between the galvanic and electric fluids, he was interrupted by Prof. Brugnatelli, who stated that Volta, who was then present, desired an opportunity to correct the wrong impressions the lecturer laboured under. Volta called upon him early the day following and brought a live frog as well as apparatus, with which they experimented quite extensively, and the results of which brought Robertson completely over to the views of the Italian scientist. Volta frequently repeated his visits, which led to the development of a lasting friendship between the two. They visited together all the prominent scientific bodies, such as l’Ecole de Médecine, l’Ecole Polytechnique, etc., but found to their great astonishment that Robertson was the only one in Paris who had as yet given the new discovery any serious attention. At pp. 250–253, Vol. I of his “Mémoires,” etc., will be found a full account of the above as well as of the very indifferent reception first given them by the celebrated Prof. Charles.

Robertson adds (p. 256 of last-named work) that he was asked by Volta to witness the latter’s notable experiments made before the members of the National Institute of France, Nov. 16, 18, 20, 1800, and already alluded to herein at A.D. 1775. The sessions of that body were being held at the time in the Palais du Louvre, and the excitement caused by the meetings was so great that all the approaches were guarded by soldiery. After Prof. Volta had explained his theory and alluded to the identity of electricity and galvanism, he announced that Robertson had first illustrated the fact, and he asked him to repeat his original experiment, which the latter did after the necessary hydrogen gas had been procured from the neighbouring cabinet of Prof. Charles.

Robertson is also the author of several other interesting memoirs on the electrophorus, the improved “couronne de tasses” and “acide galvanique” which can be found in Vol. XXXVII of the Journal de Physique and in the Journal de Paris for the year 1800 (“Recueil des Actes de la Soc. de Lyon,” Tome II. p. 370).

=A.D. 1801.=--Gerboin (A. C.), Professor at the Medical School of Strasbourg, is the first to report upon the peculiar agitation of mercury when the voltaic current passes through it.

He states, in his “Recherches expérimentales sur un nouveau mode de l’action électrique” (Strasbourg, 1808), that his many researches were instigated by the observation he had made during the winter of 1798, while in company with some friends watching a child play with a hollow wooden ball. The Italian physicist, Abbate Fortis (1740–1803), who wrote several works on natural philosophy, but who is best known by his “Viaggio di Dalmazia,” had already announced that a pyritical cube suspended by a thread held between the thumb and index would immediately, without any movement of the fingers, assume a circular motion upon being approached by another body. The “Morgenblatt” of Tübingen and the French “Archives Littéraires” render in 1807 a very complete account of Ritter’s researches upon the Fortis pendulum, and N. Meissas states, at pp. 181–187 of his “Nouveaux Eléments de Physique,” Paris, 1838, that he repeated the experiment of Ritter and of his friend Gerboin and observed many very curious results. These he embodied in a communication during the month of April 1829 to Ampère, who looked into Meissas’ work in company with M. Becquerel, also a member of the French Institute.

In his experiments, Gerboin employed a tube bent in U[ symbol] form, filled half full of mercury, which later was covered with a stratum of water, and he placed therein the wires connecting with a pile. The surface of the mercury beneath the negative pole was slightly oxidized, but the surface under the positive point moved so violently as to cause small bodies placed within to be thrown outward upon the surface of the tube. These bodies moved in a contrary direction, v from the circumference toward the interior, if the positive pole was made to touch the liquid metal.

REFERENCES.--Observations of M. Erman, of the Berlin Academy of Sciences, upon M. Gerboin’s experiments related in the _Annales de Chimie_, Tome LXXVII. p. 32. Also, Annales de Chimie, Tome XLI. pp. 196, 197, Mém. des Soc. Sav. et Lit., Vol. II. p. 199; Dr. Gore, “El. Metal,” 1877, p. 3; De la Rive, “Treatise on Electricity,” 1856, Vol. II. p. 433; Gmelin’s “Chemistry,” Vol. I. p. 487.

=A.D. 1801.=--Trommsdorff (Johann Bartholomäus), German chemist and pharmacist, who became Professor of Physics and Chemistry in the University of Erfurt, discovers that by employing large plates in galvanic batteries he can produce the combustion of fine wires and of thin leaves of metal.

After having obtained very strong shocks and large sparks, and effected the decomposition of water, etc., with his first pile consisting of 180 discs of copper, zinc and wet cardboard, he experimented with very thin leaves of the following metals, and found them to burn as follows: Gold, with a bright white light; silver, with a blue light; yellow copper, with a reddish blue light; red copper, with an emerald blue flame; zinc, with a bluish white flame; tin, with a reddish white light, etc. When oxidizing the noble or perfect metals, gold, silver, platinum, in hollow glass spheres, he found them to melt so thoroughly as to completely line the sides of the latter.

Trommsdorff afterward constructed a much larger pile of nearly 600 discs, not doubting that with a larger apparatus he could consume very thick plates. It was while carrying on subsequent experiments that MM. Fourcroy, Vauquelin and Thénard ascertained the fact that metals were more effectively deflagrated by piles with large plates than by piles having a great many plates of smaller surfaces.

In a letter dated Erfurt, March 16, 1801, Trommsdorff alludes to the galvanic decomposition of water spoken of at p. 98 of the “Archives du Nord pour la Physique et la Médecine,” published at Copenhagen, and expresses doubts as to the correctness of the conclusions therein pointed out by Pfaff and Ritter.

REFERENCES.--“Encycl. Metrop.” (Galvanism), Vol. IV. p. 221; “Roy. Soc. Sci. Papers,” Vol. VI. pp. 45–52; Poggendorff, Vol. II. pp. 1136, 1137; C. H. Wilkinson, “Elem. of Galv.,” London, 1804, Vol. II. pp. 134–136; J. S. Ersch, “Handbuch,” etc., p. 119; L. F. F. Crell, “Chemische Annalen” for 1801; 4^e Cah., p. 337; J. B. Van Mons, Journal de Chimie, Vol. I. p. 41; Larousse, “Dict. Univ.,” Vol. XV. p. 535. His pile is described at pp. 253–254, Vol. II of “Hist. du Galvanisme,” P. Sue, aîné, Paris, An. X, 1802, with references to Von Crell’s “Chemische Annalen,” 1801, 4th Book, p. 237, and Van Mons’ “Journal de Chimie,” Vol. I. p. 41.

=A.D. 1801.=--Libes (Antoine), Professor of Natural Philosophy at the Collège de Beziers and at the Paris Ecole Normale and Lycée Charlemagne, publishes in three volumes, at Paris, his “Traité élémentaire de Physique,” which had been preceded by his “Théorie de l’électricité,” etc., and was followed by a valuable “Dictionnaire de Physique” in 1806 (C. F. V. Delaunay, “Manuel,” etc., Paris, 1809).

In his “Traité,” Prof. Libes dispels the previous generally accepted belief as to the production of electricity by pressure. Experiments made by Æpinus and by Haüy had shown that such minerals as developed positive electricity by friction likewise exhibited the same electricity by pressure, and that those furnishing resinous or negative electricity by pressure developed the same electricity by friction.

It is known that varnished silk (taffetas gommé) acquires resinous electricity by ordinary friction, but Libes found the means of causing it to develop vitreous or positive electricity. This is shown when a metallic disc insulated by a glass handle is pressed upon the silk; the latter will acquire positive electricity while the disc will develop resinous or negative electricity. If, on the contrary, the disc is rubbed or rolled upon the silk so as to produce friction, the silk acquires resinous electricity and the disc vitreous or positive electricity. If a glass plate is substituted for the disc, the silk again acquires vitreous electricity and the glass resinous electricity, that is to say, they both develop contrary electricities to that furnished through ordinary rubbing.

REFERENCES.--Larousse, “Dict. Univ.,” Vol. X. p. 475; Poggendorff, Vol. I. pp. 1449, 1450; Volpicelli, “Sul cognito fenomeno ...” Roma, 1859; Haüy, “Traité Elémentaire de Physique,” Paris, 1806, Vol. I. pp. 371, 372; A. C. Becquerel, “Expériences ... par la pression,” Paris, 1823; “Catal. of Sci. Papers of Roy. Soc.,” Vol. IV. p. 5; Thos. Thomson, “An Outline of the Sciences of Heat and Electricity,” London and Edinburgh, 1830, p. 482; Dove, p. 229; “Encycl. Brit.,” Vol. VIII, 1855, p. 563; Annales de Chimie et de Physique, Vol. XXII. p. 5; Phil. Mag., Vol. LXII. pp. 204, 263.

=A.D. 1801.=--Fourcroy (Antoine François de), an eminent French chemist, physician and author, who succeeded Macquer in the professorship at the Jardin du Roi, for which Lavoisier was likewise a candidate, publishes (Vol. XXXIX. p. 103, of the Annales de Chimie) the result of galvanic experiments which he made in conjunction with Louis Nicholas Vauquelin (1763–1829), and also with Baron Louis Jacques Thénard (1777–1857), who, in turn, became the successor of Fourcroy as Professor of Chemistry at the Ecole Polytechnique. They thought that by using many discs they could increase the force of the current and also decompose water more rapidly, but found this was not the case, and that with an enlarged pile the combustion of metallic wires was more rapid and brilliant, thus proving that the degree of combustion is relative to the surface of the plates (“Encyclopædia Britannica,” 1855, Vol. XXI. p. 626).

The grand experiment made conjointly by Fourcroy, Vauquelin and Seguin on the composition of water from its constituent gases was commenced May 13, 1790, and continued by them without intermission until its completion, nine days later. “The gases were fixed in a close vessel by means of electricity, and produced a nearly equal weight of water” (Trans. Amer. Phil. Soc., N. S., Vol. VI. p. 339, giving description of apparatus for the decomposition and recomposition of water).

Fourcroy was also one of the savants appointed in 1798 by the Academy of Sciences of Paris to examine and report upon the experiments of Galvani. The committee was composed of Guyton de Morveau, Coulomb, Vauquelin, Sabathier, Pelletan, Charles, Fourcroy and Hallé, the last named being charged with the verification of all the then recent discoveries, which were repeated with the assistance of Humboldt, who went to Paris especially for the purpose. The official report fully endorsed the praiseworthy line of researches prosecuted by both Galvani and Humboldt, and the entire series of experiments was at once repeated by many leading physicists throughout Germany.

On June 19, 1803, one of Antoine Fourcroy’s most interesting memoirs, treating of meteoric stones, was read by C. Fourcroy before the French Institute.

REFERENCES.--Phil. Mag., Vol. XVI. p. 299; Noad’s “Lectures,” pp. 183, 184; Ure, “Dict. of Chem.”; also the interesting biography embracing a list of his very numerous works and treatises, at pp. 846–849, Vol. IX of 1855 “Encyclopædia Britannica.” See likewise, “Royal Society Catalogue of Scientific Papers,” Vol. II. pp. 677–682; Thomas Thomson, “History of Royal Society,” p. 454; Wilkinson’s “Elements of Galvanism ...” 1804, Vol. II. pp. 113, 145, 151, 152, 208, 359; Fahie’s “History of Electric Telegraphy,” p. 194; Izarn, “Manuel du Galv.,” 1804, s. 4, p. 167; “Journal des Savants” for Jan. 1860; P. Sue, aîné, “Hist. du Galvanisme,” Paris, 1802, Vol. II. pp. 159–160, 241, 264. For Louis N. Vauquelin, consult “Cat. Sc. Papers of Roy. Soc.,” Vol. VI. pp. 114–128, 761; also “Mém. des Soc. Savantes et Litt.,” Vol. I. p. 204.

=A.D. 1801.=--Lehot (C. J.), French physicist, sends a curious and lengthy memoir, regarding the circulation of a very subtile fluid in the galvanic chain, to the Institut National, before which body it is read on the 26 Frimaire, An. IX.

To the analyzation of the above-named memoir, Wilkinson devotes more than half the tenth chapter of his “Elements of Galvanism,” calling attention to a very singular result from numerous experiments which is worthy of special mention. It is the possibility of actually distinguishing one metal from another without seeing or feeling either of them, and he says that by his arrangement of the chain, M. Lehot was able to recognize a portion of zinc from a piece of silver, at the extremity of metallic threads several yards in length.

Lehot’s contributions to the science of animal electricity are too numerous to be given here. Noad summarizes them in the translation from pp. 17, 18 of C. Matteucci’s “Traité des phénomènes ...” Paris, 1844.

He ascertained that in a recently killed animal contractions are excited by the electric current in whatever direction it may be applied, but, when the vitality of the animal has become diminished, if the current is sent in the direction of the ramifications of the nerves, contractions are produced only at the commencement of the current; the reverse takes place when the current is directed contrary to the ramifications of the nerves; i. e. in this case the contractions only take place when the current ceases. After studying the sensation excited by the current on the organs of taste, Lehot concluded that the current which traverses a nerve in the direction of its ramifications excites a sensation when it ceases to pass, though this influence is only exerted at the commencement of its passage when the nerve is traversed in a direction contrary to its ramifications. The later experiments of Carlo Francesco Bellingeri and Stefano Giovanni Marianini entirely confirm those of Lehot.

REFERENCES.--Annales de Chimie, Vol. XXXVIII. p. 42; _Journal de Physique_, An. IX, Pluviose, LII. 135; Gilbert, Annalen, IX. 188; P. Sue, aîné, “Hist. du Galvanisme,” Vol. II. pp. 123, 124, 129, 132, 141,142; “Encyclopedia Metropolitana,” Vol. IV (“Electro-Magnetism,” p. 8).

=A.D. 1801.=--Wollaston (William Hyde), celebrated English chemist and natural philosopher, an associate of Sir Humphry Davy, who had taken the degree of M.D., and joined the Royal Society in 1793, but soon abandoned the practice of medicine to devote himself exclusively to scientific researches, is the first to demonstrate the identity of galvanism and frictional electricity, through a paper read before the above-named society in June 1801.

The latter communication shows that he succeeded in decomposing water as rapidly by means of mere sparks from frictional electricity as through the agency of the voltaic pile, and in a more tranquil and progressive manner than can be assured through shocks from large and powerful apparatus. He concluded that the decomposition must depend upon duly proportioning the strength of the charge to the quantity of water, and that the quantity exposed to its action at the surface of communication depends on the extent of that surface. He observes:

“Having procured a small wire of fine gold, and given to it as fine a point as I could, I inserted it into a capillary glass tube, and after having heated the tube so as to make it adhere to the point and cover it at every part, I gradually ground it down till, with a pocket lens, I could discern that the point of gold was disclosed. I coated several wires in this manner, and found that when sparks from a conductor were made to pass through water by means of a point so guarded, a spark passing to the distance of ⅛ of an inch would decompose water, when the point did not exceed ¹⁄₇₀₀ of an inch in diameter. With another point, which I estimated at ¹⁄₁₅₀₀, a succession of sparks ¹⁄₂₀ of an inch in length afforded a current of small bubbles of air. With a still finer filament of gold, the mere current of electricity, without any perceptible sparks, evolved gas from water.”

In his Bakerian lecture of Nov. 20, 1806, Sir Humphry Davy relates experiments made after the manner contrived by Wollaston, showing that the principle of action is the same in common as in voltaic electricity. Dr. Robert Hare, in a paper read before the Academy of Natural Sciences, “On the Objections to the Theories Severally of Franklin, Dufay and Ampère,” etc., says that, instead of proving the identity of galvanism with frictional electricity, the above-named experiments show that in one characteristic at least there is a discordancy, but that at the same time they possibly “indicate that ethereal may give rise to ethereo-ponderable undulations.” Noad remarks that in these ingenious experiments true electro-chemical decomposition was not effected; that is, “the law which regulates the transference and the final place of the evolved bodies had no influence.” The water was decomposed at both poles independently of each other, and the oxygen and hydrogen gases evolved at the wires are the elements of the water before existing in those places. Faraday observes:

“That the poles, or rather points, have no mutual decomposing dependence, may be shown by substituting a wire or the finger for one of them, a change which does not at all interfere with the other, though it stops all action at the charged pole. This fact may be observed by turning the machine for some time; for though bubbles will rise from the point left unaltered in quantity sufficient to cover entirely the wire used for the other communication, if they could be applied to it, yet not a single bubble will appear on that wire.”

Wollaston communicated a paper to the Royal Society (Phil. Trans., Vol. XCI. p. 427) showing that the oxidation of the metal is the primary cause of the electrical phenomena obtained in the voltaic pile. The oxidating power is finely shown by his eighth experiment, which he thus describes:

“Having coloured a card with a strong infusion of litmus, I passed a current of electric sparks along it, by means of two fine gold points, touching it at the distance of an inch from each other. The effect, as in other cases, depending on the smallness of the quantity of water, was most discernible when the card was nearly dry. In this state a very few turns of the machine were sufficient to occasion a redness at the positive wire, very manifest to the naked eye. The negative wire, being afterward placed on the same spot, soon restored it to its original blue colour.”

He verified in 1802 the laws of double refraction in Iceland spar announced by Huyghens, and wrote a treatise thereon which was read before the Royal Society on the 24th of June, and which contains additional evidence deduced from Dr. Wollaston’s superior mode of investigation.

He is said to have been the first to propose forming the spectrum by using a very narrow pencil of daylight instead of sunlight, and to have first made an accurate examination of the electric light. In his communication to the Philosophical Transactions for 1802 he says:

“When the object viewed is a blue line of electric light, I have found the spectrum to be separated into several images; but the phenomena are somewhat different from the preceding (viz. the spectrum of the blue portion of the flame of a candle). It is, however, needless to describe minutely appearances which vary according to the brilliancy of the light, and which I cannot undertake to explain.”

During the year 1815, Wollaston made a great improvement in the construction of voltaic batteries. Having observed that the power of a battery is much increased with a corresponding economy in zinc plates, when both zinc surfaces are opposed to a surface of copper, he devised what he called an elementary galvanic battery. Each couple of the latter is made up only of a plate of copper doubled up around a zinc plate from which it is kept apart by strips of cork or wood, and the connecting strips of metal are attached to a wooden rod which is lowered or elevated when the battery is in or out of action. He found that a properly mounted plate of zinc, one inch square, was more than sufficient to ignite a wire of platina ¹⁄₃₀₀₀ of an inch in diameter, even when the acid is very diluted (fifty parts of water to one of sulphuric acid).

He was a very careful workman, and in order to adapt his apparatus to the popular uses, he generally endeavoured to construct them upon the most reduced scale (dans des proportions très exigues). He produced platinum wire so extremely fine as to be almost imperceptible to the naked eye. It was estimated that 30,000 pieces of this wire, placed side by side in contact, would not cover more than an inch; that it would take 150 pieces of this wire bound together to form a thread as thick as a filament of raw silk, and that a mile of this wire would not weigh more than a grain. It may be well to add here that the wire made with John Wennstrom’s sapphire plates, for delicate electrical apparatus, is so fine that thirty-six miles of it, properly insulated for Government use in torpedo experiments, measures only about five inches in length by three in diameter when wound upon a spool. The fibre used as carbon filaments in the incandescent lamps is scraped to an even thinness by being drawn through sapphire plates from ³⁰⁄₁₀₀₀ to ⁴⁄₁₀₀₀ of an inch in diameter.

The smallest battery that Wollaston formed of the above-described construction consisted of a thimble without its top, flattened until its opposite sides were about two-tenths of an inch asunder. The bottom part was then nearly one inch wide and the top about three-tenths, and as its length did not exceed nine-tenths of an inch, the plate of zinc to be inserted was less than three-fourths of an inch square (Annals of Philosophy, Vol. VI. p. 210).

We are also indebted to Dr. Wollaston for the first idea of the possibility of producing electro-magnetic rotations. Prof. Schweigger opposed the action of revolving magnetism upon the ground that if it were true, a magnet might be made to revolve around the uniting wire, but Faraday found experimentally not only that a magnet could be made to revolve round the uniting wire, but that a movable uniting wire might be made to revolve around a magnet. (See Faraday’s “Experimental Researches,” Vol, II. pp. 159–162 for “Historical Statement Respecting Electro-magnetic Rotation.”)

Wollaston was made secretary of the Royal Society in 1806, became its president in 1820 after the death of Sir Joseph Banks, and contributed in all thirty-eight memoirs to the Philosophical Transactions of that Institution.

His death occurred Dec. 22, 1828, and during the following February Dr. Fitton, President of the Geological Society, concluded his annual address with the following encomium:

“It would be difficult to name a man who so well combined the qualities of an English gentleman and a philosopher, or whose life better deserves the eulogium given by the first of our orators to one of our most distinguished public characters; for it was marked by a constant wish and endeavour to be useful to mankind.”

REFERENCES.--Phil. Mag. or Annals, Vol. V. p. 444. See also “The Roll Call of the Royal College of Physicians of London,” by William Munk, M.D., Vol. II; Edin. Phil. Jour., Vol. X. p. 183; Gmelin’s “Chemistry,” Vol. I. p. 424; De la Rive, “Treatise on Electricity,” pp. 444, 445; Phil. Mag., Vol. XXXIII. p. 488; LXIII. p. 15; James Napier, “Manual of Electro-Metallurgy,” 4th Am. ed., pp. 492, 518; Desbordeaux, in Comptes Rendus, Vol. XIX. p. 273; Le Moniteur, No. 40 for 1806; Sue, aîné, “Galvanisme,” Vol. II. pp. 193–195, 199, 202; Joseph Izarn, “Manuel du Galvanisme,” p. 137; Poggendorff, Vol. II. p. 1362; “Encycl. Metrop.,” Vol. IV (Galvanism), pp. 180, 181, 216, 222; Nicholson’s Journal, Vol. V. p. 333; Thos. Young, “Lectures,” London, 1807, Vol. II. p. 679; W. Sturgeon, “Scientific Researches,” Bury, 1850, p. 29; Quarterly Journal of Science for January 1821; British Quarterly Review for August 1846; “Biog. Générale,” Tome XLVI. p. 822; Highton’s “Electric Telegraph,” p. 14; Larousse, “Dict. Universel,” Tome XV. p. 1370; “Cat. Sc. Papers ... Roy. Soc.,” Vol. I. p. 61; Vol. II. pp. 136, 199; “Bibl. Britan.,” 1801, Vol. XVIII. p. 274; 1810, Vol. XLIII. p. 347 (Phil. Mag., June 1809); Vol. I., N.S., 1816, p. 119.

=A.D. 1802.=--Walker (Adam), English writer and inventor of several very ingenious mathematical instruments, publishes in London his enlarged edition of “A System of Familiar Philosophy,” two volumes, 8vo, in which he devotes ss. 5–9 of Lecture II. vol. i. to magnetism, and all of Lectures VII and VIII of the second volume to electricity.

We are informed, through his preface, that “the identity of fire, light, heat, caloric, phlogiston and electricity, or rather their being but modifications of one and the same principle, as well as their being the grand agents in the order of nature ... are the leading problems of the work.” In another part he tells us:

“If electricity, light and fire be but modifications of one and the same principle ... and they have their origin or foundation in the sun, it is natural to suppose, in issuing from that luminary, they proceed from him first in their purest state, or in the character of electricity; that joining the particles of our atmosphere, electricity becomes light, and uniting with the grosser earth, fire ... that this fire shall be culinary when called forth from the earth by ordinary combustion, and electric when called forth by friction. Thus have I exhibited this wonderful agent in most of the lights in which it has yet been seen; and flatter myself the reader’s deductions from these appearances will be similar to my own, viz. that electricity emanates in a perfect state from the sun and fixed stars; that its particles repel each other and fill all space; that they have an affinity to the earth and planets, but an affinity that cannot easily be gratified, because the surrounding atmospheres are in part non-conductors, being already saturated, and, of course, repellent of the electric fluid” (Lecture VIII. p. 72).

In the section devoted to “Miscellaneous Observations,” he remarks that the magnetic power may almost be said to be created by friction, rather than communicated by it; for a magnet acquires strength by giving magnetism to iron; so that, if all the magnets in the world were lost, magnetism might be revived by rubbing the end of one steel bar against the side of another.

Section V, treating of “Magnetic Attraction,” concludes as follows: “How far these observations and experiments go to establish the doctrine of a magnetic effluvium flowing through the earth, or from one end of a magnet to the other, must be left to the reader’s judgment and opinion. We are apt to laugh at the subtil matter of Descartes and the aether of Euler, as occult qualities, which modern philosophy will not admit into its creed, but this effluvium is a subtil matter, an aether, equally as inexplicable and as equally out of the reach of our five senses to scrutinize; however, if we may venture to guess at causes by effects, and to compare analogies with what we can see, feel, etc., I think we have infinite data in favour of an electro-magnetic fluid, superior to any proof that can be brought of æther being the cause of gravity, light, vision, etc.”

John Read’s letter to the author concerning the electrophorus appears at pp. 47–49 of the second volume (Poggendorff, Vol. II. pp. 1248–1249).

=A.D. 1802.=--Alexandre (Jean), who is said to have been the natural son of Jean Jacques Rousseau, and to have studied for the medical profession, operates his secret telegraph (télégraphe intime) at Poitiers, and afterwards addresses M. Chaptal, Ministre de l’Intérieur, asking for financial aid in order that he may be enabled to go to Paris and submit his invention to the French Government. This request being refused on account of Alexandre’s unwillingness to divulge his secret, he next obtained an audience of M. Cochon, Prefect of Vienne, before whom he demonstrated his invention so successfully that the latter was induced to make a report of it to M. Chaptal, advising him to invite Alexandre to Paris at the expense of the State. A second refusal, however, followed, and Alexandre went to Tours, where he there also failed to obtain the desired assistance, after giving successful exhibitions of his telegraph before the Prefect of Indre-et-Loire, General Rommereul, as well as before the Mayor and the city officials.

The substance of Prefect Cochon’s communication is to be found translated at pp. 111–113 of Fahie’s “History of Electric Telegraphy,” which latter also contains a full translation of the report addressed, 10 Fructidor, An. X by the celebrated French astronomer, J. B. J. Delambre, to the First Consul, suggesting for the inventor’s representative, M. Beauvais, an interview which Bonaparte, however, refused to grant.

Alexandre died, 1832–1833, without having revealed his secret to any one but M. Beauvais. It is stated by Fahie that in the English Chronicle of June 19–22, 1802, appears a brief account of the above-named exhibition given at Tours, concluding as follows: “The art or mechanism by which this is effected is unknown, but the inventor says that he can extend it to the distance of four or five leagues, even though a river should be interposed.” A copy of the above-named newspaper, doubtless unique, was in Latimer Clark’s library.

REFERENCES.--“Annales Télégraphiques,” March-April, 1859, pp. 188–199, for M. Edouard Gerspach’s Memoir; “Sci. Am. Suppl.,” No. 384, for a translation of M. Auguste Guéroult’s article in “La Lumière Electrique”; M. Cézanne, “Le Cable Transatlantique,” Paris, 1867, p. 32; M. Bério, “Ephemerides of the Lecture Society,” Genoa, 1872, p. 645.

=A.D. 1802.=--Sue (Pierre, aîné), a very able French physician, publishes, at Paris, “Histoire du Galvanisme et analyse des différents ouvrages publiés sur cette découverte ...” which is considered by scientists one of the most important works on the subject.

REFERENCES.--“Biographie Générale,” Vol. XLIV. pp. 618–619; Larousse, “Dictionnaire Universel,” Vol. XIV. p. 1200; Wilkinson, “Elem. of Galv.,” 1804, Vol. I. p. 182.

=A.D. 1802.=--Brugnatelli (Luigi Valentino), who, after being a pupil, became the close friend and subsequently the colleague of Volta at the Pavia University, is the first to obtain, by means of the voltaic pile, a decidedly practical result in electro-plating. He gilded two large silver medals on bringing them in communication, by means of the steel wire, with the negative pole of a voltaic pile, and by keeping them one after the other immersed in ammoniurets of gold newly prepared and well saturated (Phil. Mag. for 1805).

He also electro-deposited bright metallic silver upon platinum, and observed that when the current entered the liquid by means of a pole of copper or zinc, those metals were dissolved and then deposited upon the negative pole. Spon tells us (“Dictionary of Engineering,” London, 1874, Vol. II. p. 1378) that the solutions employed by Brugnatelli were alkaline; they consisted of ammoniurets of gold, silver or platina, that is, the product obtained by treating the chlorides of gold and platina or the azotate of silver, by ammonia. There is much obscurity in the descriptions of Brugnatelli, but according to the Journal de Physique et Chimie of Van Mons, the most expeditious method of reducing, by means of the battery, dissolved metallic oxides, is to make use of their ammoniurets by placing the ends of two conducting wires of platina into ammoniuret of mercury. The wire of the negative pole speedily becomes covered with small particles of this metal. MM. Barral, Chevalier and Henri tried to reproduce Brugnatelli’s operation by following his descriptions, but with very imperfect results, the nature of the dissolvent employed by the learned Italian not being known.

At p. 136, Vol. XVIII of his Annali di Chimica, etc., Brugnatelli publishes a memoir entitled “Chemical Observations on the Electric Acid.” He says:

“Naturalists have hitherto merely abandoned one erroneous hypothesis for another, in considering the nature of the electric fluid. Some have regarded it as identical with heat; while others have been led to consider it as a modified caloric. The disciples of Stahl ascribed it to the nature of their phlogistic or, at least, supposed it to be a fluid abundantly provided with that principle. Henley conjectured it to be phlogistic, when in a state of repose, and fire, when in a state of activity. Among the moderns, several have been found who have declared it to be an acid; but their opinion has been combated by Gardini, who, by means of several ingenious observations, has endeavoured to demonstrate that it is composed of caloric and hydrogen.”

In the earlier experiments on the decomposition of even chemically pure water by the voltaic column, the presence of an acid was always apparent at the pole evolving oxygen, while alkaline matter appeared at the other (Nicholson’s Journal, quarto, Vol. IV. p. 183).

Mr. William Cruikshanks supposed the former to be the nitrous acid resulting from a combination of the oxygen at the positive pole with the azote of the air held in solution by the water, while the alkali, he said, proceeded from the combination of the same principle with the hydrogen evolved at the negative pole (Nicholson’s Journal, quarto, Vol. IV. p. 261). Mr. C. B. Desormes afterward endeavoured to show that the products were ammonia and muriatic acids (Annales de Chimie, Vol. XXXVII. p. 233). Brugnatelli’s experiments with the couronne de tasses, however, led him to consider it to be an acid sui generis produced by the combination of one of the constituents of water with positive electricity. He classed it as oxi-electric, and of all the metals, gold and platina alone appeared to him not to be sensibly affected by this electric acid.

REFERENCES.--For Brugnatelli’s record of other experiments and observations and for his Memoirs upon different piles, upon animal electricity, upon the identity of the electric and galvanic fluids, etc. etc., see his “Principes,” etc., 1803, and “Grundsätze des Elektricität,” etc., 1812, his Annali di Chimica, Vols. VII. p. 239; XIX. pp. 77, 153, 274, 277, 280–281; XXI. pp. 3, 143, etc., 239; XXII. pp. 1, etc., 77–92, 257, 301; the Giornale di Chimica, Fis. e Storia Nat. of L. and G. Brugnatelli, G. Brunacci and P. Configliachi, Vol. I. pp. 147–163, 337–353; IX. p. 145; XI. p. 130, and the “Commentarii Medici,” edited by L. Brugnatelli and L. V. Brera; also Brugnatelli’s Giornale Fisico-Medico, etc., and its continuation, Avanzamenti della Medicina e Fisica, the first named containing (Vol. I. p. 280), a repetition of Galvani’s experiments, made by Volta, Rezia and Brugnatelli; G. Bianconi, “Intorno ...” and “Cenni intorno ... Galvanoplastica” (Nuovi Annali della Scienze Naturali); the “Biblioteca Italiana,” of which his son Gaspare Brugnatelli was an editor, in conjunction with Breislak, Configliachi, Carlini, Cotena, Acerbi, Brunacci, Fantonelli, Fumagelli, Ferrario, Giordiani, Gironi and Monti; G. A. Giobert, “Gior. Fis. Med.,” 1188; Du Pré, “Ann. di Chimica,” IX. 156; P. Mascagni, “Lettera ...” for Brugnatelli’s notes; A. Cossa, “Notizie ... elettro-chimica,” 1858; J. Napier, “Man. of El. Met.,” 4th ed., pp. 491, 492; J. B. Van Mons’ Journal de Chimie, Vols. I. pp. 1, 24, 101, 216, 325; II. pp. 106, 216; IV. p. 143; X. p. 114; XVI. p. 132; also Vol. LXXVI; Giornale di Fis. Chim., Vol. I. pp. 4–32, 28, 139–147, 164–166, 338; “Effemeridi Chim. Mediche di Milano,” 1807, Sem. I. p. 57; A. F. Gehlen’s Journal für die Chemie, Vol. I. pp. 54–88; VI. pp. 116–124; VIII. pp. 319–359; L. W. Gilbert, Annalen der Physik, Vols. VIII. pp. 284–299; XVI. pp. 89–94; XXIII. pp. 177–219; Philosophical Magazine, Vols. XXI. p. 187; XXV. pp. 57–66, 130–142; LIII. p. 321; Dr. Thos. Thomson’s Annals of Philosophy, Vol. XII. p. 228; Alfred Smee’s “Elements of Electro-Metallurgy,” History, pp. xxv-xxvi; Journal de Pharmacie, Vol. III. pp. 425, 426; J. Nauche, Journal du Galvanisme, etc., Vol. II. pp. 55–60; P. Sue, aîné, “Histoire du Galvanisme,” An. X, 1802, Vol. I. p. 305; II. pp. 263, 316, 320, 328; Annales de Chimie, Feb. 1818; for Brugnatelli, “Biblioth. Britan.,” Vol. XXXI., 1806, pp. 43, 122, 223 (pile végétale).

=A.D. 1802.=--Jäger (Karl Christoph Friedrich van), a well-known physicist of Wurtemberg and professor at Stuttgart, confirms by mathematical analysis the theory of electrical distribution and equilibrium, as will be seen by his papers in Gilbert’s Annalen der Physik, Vols. XII. pp. 123, 127; XIII. pp. 399–433; XXIII. pp. 59–84, and LII. pp. 81–108.

The views of Jäger were fully endorsed by Berzelius, who, like Scholz and Reinhold, endeavoured to extend them, and who says that we are indebted to the German physicist for actually the most complete elucidation of the theory of the voltaic pile.

In Vol. XLIX of Gilbert’s Annalen for 1815, pp. 47–66, will be found Jäger’s observations and experiments on Zamboni’s column as well as the papers of Zamboni and Deluc on dry piles. Dr. Thomson says that since Dr. Jäger found that, when the temperature was raised to 104 degrees, or as high as 140 degrees, the pile begins again to act as well as ever, we must conclude from this that dry paper, while cold, is a nonconductor of electricity, but that it becomes again a conductor when heated up to 104 degrees or 140 degrees.

REFERENCES.--Poggendorff, Vol. I. pp. 1186, 1187; “Catalogue of Scientific Papers of the Royal Society,” Vol. III. p. 525; Jäger on the tourmaline in Gilbert’s Annalen for 1817, Vol. LV. pp. 369, 416, and Jäger, Bohnenberger and Zamboni in the Annalen for 1819, Vol. LXII. pp. 227–246; Figuier, “Expos. et Histoire,” 1857, Vol. IV. p. 433; Davy, “Bakerian Lectures,” 1840, pp. 44–56, on the “Agencies of Electricity.”

=A.D. 1802.=--Gale (T.), an American physician, publishes at Troy “Electricity or Ethereal Fire ... considered naturally, astronomically and medically, and comprehending both the theory and practice of medical electricity,” etc. Among other things, he describes at pp. 27, 28, various experiments made with his galvanometer; explains at pp. 46–64 how the Newtonian principles are erroneous; and shows at p. 264 how to extract lightning from the clouds; while at pp. 272, etc., are given directions for using electricity both as a sure preventive and cure of diseases.

=A.D. 1802.=--Gibbes (George Smith), M.D., of Bath, reads before the Royal Society a paper on the Phenomena of Galvanism thus noticed by Dr. Young at pp. 672, 673, Vol. II. of his “Course of Lectures,” London, 1707:

“Dr. Gibbes begins with reciting some experiments on the oxidation produced during the union of tinfoil with mercury, first in the air and then under water. He assumes a different opinion from that of Dr. Wollaston, respecting the origination of electricity in chemical changes, and maintains on the contrary that the electrical changes are to be considered as preceding and favouring the chemical. He imagines that the simple contact of various substances produces changes of electrical equilibrium, and that the action of acids is effectual in promoting these changes, by bringing their surfaces into contact. Dr. Gibbes observes upon Dr. Wollaston’s experiment of immersing zinc and silver in an acid solution, that if they are placed in two separate portions of the fluid, and the parts not immersed are brought into contact there is no emission of gas from the silver; but that it is copiously produced when the contact takes place in the same fluid. He proceeds to relate some experiments which seem to show a difference between galvanism and electricity, particularly that galvanism does not appear to be attracted by metallic points. He also states an experiment in which a piece of paper is placed on tinfoil, and rubbed with elastic gum, and although the tinfoil is not insulated, sparks are produced on raising the paper. Dr. Gibbes concludes with some arguments against the doctrine of the decomposition of water; and advances as a probable opinion, that oxygen and hydrogen gas are composed of water as a basis, united with two other elements, which, combined, form heat.”

As remarked by Wilkinson (“Elements of Galvanism,” London, 1804, Vol. II. pp. 385, 386), Dr. Gibbes’ hypothesis as to the composition of water having been deduced from Richter’s experiments, and these latter proving erroneous, the ingenious superstructure which the doctor has erected must necessarily fall to the ground.

=A.D. 1802.=--Romagnosi (Gian Domenico Gregorio Giuseppe), Italian jurist of Salsomaggiore, near Piacenza, who had devoted much time to scientific investigation, and was about taking the law professorship at the Parma University, communicates, Aug. 3, 1802, to the Gazetta di Trento, his important paper entitled “Articulo sul Galvanismo.” Of the latter, a translation, made from the reprint at p. 8 of Gilb. Govi’s “Romagnosi e l’Elettro-magnetismo,” appears at pp. 259, 260 of Fahie’s “History of Electric Telegraphy.”

To Romagnosi has by many been given the credit of having discovered the directive influence of the galvanic current upon a magnetic needle. This claim has of late years been again made for him, notably by Dr. Donato Tommasi, of Paris (Cosmos, les Mondes of June 30, 1883), while Dr. J. Hamel endeavoured to prove (pp. 37–39 of “Historical Account ... Galv. and Mag. Elec. ...” reprinted by W. F. Cooke for the Society of Arts, London, 1859) that Oersted was aware of Romagnosi’s experiments at the time he published the discovery of electro-magnetism. This is what Dr. Hamel says:

“I cannot forego stating my belief that Oersted knew of Romagnosi’s discovery announced in 1802, which was eighteen years before the publication of his own observations. It was mentioned in the book of Giovanni Aldini (the nephew of Galvani) ... Oersted was in Paris 1802 and 1803, and it appears from the book of Aldini, that at the time he finished it Oersted was still in communication with him; for he says at the end (p. 376) he had not been able to add the information received from Oersted, Doctor of the University at Copenhagen, about the galvanic labours of scientific men in that country.... It deserves to be remembered, that from Aldini’s book (“Essai théorique et expérimental sur le galvanisme,” etc., Paris, 1804, qto. p. 191, or Vol. I. of the 8vo ed., pp. 339–340) it was known that the chemist, Giuseppe Mojon (Joseph Mojon, in the French), at Genoa, had before 1804 observed in unmagnetized needles exposed to the galvanic current ‘a sort of polarity.’ Joseph Izarn repeats this also in his ‘Manuel du Galvanisme’ (Paris, An. xii., 1804, sec. iii. p. 120, or 1805, sec. ix.), which book was one of those that by order were to be placed in the library of every lycée of France.”

Robert Sabine remarks (“The Electric Telegraph,” 8vo., 1867, p. 22; “History of the Electric Telegraph,” in Weale’s Rudimentary Treatises, 1869, pp. 23, 24; “History and Progress of the Electric Telegraph,” 3rd ed., 1872, p. 23):

“The discovery of the power of a galvanic current to deflect a magnetic needle, as well as to polarize an unmagnetized one, were known to, and described as early as 1804, by Prof. Izarn.... The paragraph which especially refers to this subject is headed ‘Appareil pour reconnaitre l’action du galvanisme, sur la polarité d’une aiguille aimantée.’ After explaining the way to prepare the apparatus, which consists simply in putting a freely suspended magnetic needle parallel and close to a straight metallic conductor through which a galvanic current is circulating, he described the effects in the following words: ‘According to the observations of Romagnosi, a physicist of Trent, a magnetized needle which is submitted to a galvanic current undergoes (éprouve) a declination; and according to those of J. Mojon, a learned chemist of Genoa, unmagnetized needles acquire by this means a sort of magnetic polarity.’ To Romagnosi, physicist of Trent, therefore, and not, as is generally believed, to Oersted, physicist at Copenhagen (who observed, in 1820, the phenomenon of the deflection of a magnet needle by a voltaic current), is due the credit of having made this important discovery.”

On the other hand, Gilb. Govi, who gives in his afore-named work a good illustration of Romagnosi’s experiment, explains that it resembles in no way the experiment of Oersted, there being no magnetic action of the column on the magnetic needle, which latter is in fact repelled by the mere electricity of the pile. Ronalds states that Romagnosi’s experiment, much like that made by Schweigger (A. F. Gehlen’s Journal für die Chimie und Physik, 1808, pp. 206–208), was a modification if not a repetition of the one which Thomas Milner performed with static electricity (T. Milner’s “Experiments and Observations in Electricity,” London, 1783, p. 35), wherein a magnetic needle forms the electrometer since improved upon by J. C. A. Peltier.

To the ordinary mind, a conclusive proof that Romagnosi had no part in the discovery of electro-magnetism would seem to be, as Fahie rightly observes, the fact that he himself never claimed any, although he lived until 1835, fifteen years after the announcement made by the Danish philosopher. Fahie calls attention, for some experiments in the same line, to J. B. Van Mons’ Journal de Chimie, Bruxelles, January 1803, p. 52, and to Nicholson’s Journal of Nat. Phil., Vol. VII. p. 304, as well as to the 1746 and 1763 Phil. Trans. for investigations made by B. Robins and Ebenezer Kinnersley, and he likewise alludes to others recorded in the Amer. Polytechnic Review for 1831, and in the Quarterly Journal of Science and the Arts for 1826, to all of which, he says, as little real attention should be given as can properly be attached to the observations of Aldini and of Izarn previously referred to.

REFERENCES.--“Notizia di G. D. Romagnosi, stesa da Cesare Cantù,” Milan, 1835; “Nuova Scelta d’ Opuscoli,” Vol. I. p. 201; Gazetta di Roveredo for 1802, No. 65; “Atti della Reale Accad. delle Scienze di Torino,” Vol. IV, April 7, 1869; J. C. Poggendorff, Vol. II. pp. 681, 682; S. I. Prime’s “Life of Morse,” 1875, p. 264; Phil. Mag., Vol. LVIII. p. 43; Journal Soc. of Arts, April 23, 1858, p. 356, and July 29, 1859, pp. 605, 606; Bibl. Ital., Vol. XCVIII. p. 60; Gilbert, Annalen, 1821, Vol. LXVIII. p. 208; Larousse, “Dict. Univ.,” Vol. XIII. p. 1318; “Biographie Générale,” Vol. XLII. pp. 574, 575, the last named remarking that the discovery alluded to in the works of Aldini and Izarn passed unnoticed till Oersted caused its value to be fully appreciated.

=A.D. 1802.=--Parrot (George Friedrich), Russian physician and professor at Dorpat, is, of all the European savants, the one who developed most extensively the chemical theory of the voltaic pile. The superior manner in which all his observations were carried on have led many to consider him justly entitled to the credit of being the founder of the theory (Figuier, “Exposition et Histoire,” etc., Paris, 1857, Vol. IV. chapitre viii. pp. 426–429).

He commenced his experiments in 1801, and first recorded them in a memoir which was crowned the same year by the Batavi Scientific Society of Haarlem. His other papers on the same subject followed in rapid succession, mainly through L. W. Gilbert’s Annalen der Physik, under such heads as: “Sketch of a New Theory of Galvanic Electricity, and Concerning the Decomposition of Water,” etc. (“Combination of Induction and Chemical Action,” Gilb., Vol. XII. p. 49, Seypfer, p. 200), “How to Measure Electricity,” “Relative to the Electrometer,” “The Effects of the Condenser,” and “The Theory of Volta Concerning Galvanic Electricity,” all of which appeared in Vol. LXI. of the Annalen. These papers were alluded to in his letter to the editors of the Annales de Chimie et de Physique (An. Ch. et Phys., Vol. XLII. p. 45), and were afterward greatly amplified in his “Treatise on Natural Philosophy.”

Parrot started with the determination to demolish completely the theories of Volta and to thoroughly instruct him anew (instruire de toutes pièces le procès du physicien de Pavie), and it must be admitted that the many important facts enounced by Parrot were such as would have ordinarily created a disturbing influence, but they became known after Volta’s views had been thoroughly espoused by many German and French scientists and consequently attracted comparatively little attention.

At p. 466, Vol. II of Dr. Thomas Young’s “Course of Lectures,” London, 1807, reference is made to a paper in Gilbert’s Annalen der Physik (X. p. 11, also XIII. p. 244), concerning Parrot’s theory of evaporation, with mention of the fact that the same paper contains a proposal for inoculating the clouds with thunder and lightning, by projecting bombs to a sufficient height.

Parrot also devised a scheme for telegraphing, which is described in the Mem. Acad. Petropol., ser. vi. Vol. I for 1838, and is alluded to in the Report on Telegraphs for the United States, made at request of the Hon. Levi Woodbury, Secretary of the Treasury, by the Committee on Science and the Arts of the Franklin Institute. The proposed telegraph, as worded in the Report, “consists of a single arm or indicator, which should be about nine feet long and one foot wide, with a cross-piece at one end, about three feet long and one wide; the whole being movable about an axis at its centre.... The movements may be communicated with ease and certainty, either by an endless chain passing over a wheel on the axis, and a wheel in the building; or by a cog-wheel on the axis, and an endless screw on a vertical bar. For night signals, three lamps are used, one swinging beyond the end of the arm, the other two beyond the ends of the cross-piece.”

REFERENCES.--Gilbert’s Annalen, Vols. XXI for 1805, LV for 1817, LX for 1819; J. H. Voigt’s Magazin, Vol. IV; Grindel’s “Russ. Jahrb. f. Chem. u. Pharm.,” XI, 1810; L. Turnbull, “Elec. Mag. Tel.,” p. 19; “Naturwiss. Abhandl. aus Dorpat.,” I, 1823; “Roy. Soc. Cat. of Sc. Papers,” Vol. IV. pp. 765–767; Annales de Chimie, Vol. XLII, 1829, pp. 42–45, and Vol. XLVI, 1831, p. 361; “Mém. sixième série Sc. Mathém.,” first part of Vols. III and V; “Pander’s Beitr. z. Naturk, I.”

=A.D. 1802–1806.=--Berzelius (Baron Jöns Jacob Freiherr von), M.D., one of the greatest of modern chemists, native of East Gothland, Sweden, publishes his “De Electricitatis ...” or “Physical Researches on the Effect of Galvanism upon Organized Bodies,” which established his reputation as an experimental philosopher and procured for him the appointment of Assistant Professor of Medicine, Botany and Chemical Pharmacy at Stockholm. Of the very great number of scientific papers which he communicated to learned Societies, that entitled “An Essay on the Division of Salts through Galvanism” deserves especial mention, for in it, he lays down the electro-chemical theory, the honour of being the original propounder of which is by many claimed for Sir Humphry Davy.

In conjunction with Gottlieb Gahn, with W. Hisinger, of Elfstorps Bruk, and with the Swedish physician, Magnus Martin de Pontin, Berzelius made many very extensive observations and published numerous treatises, the most important of which are embraced in the papers named at foot (Sir Humphry Davy, “Bakerian Lectures,” London, 1840, more particularly at pp. 13, 20, 109, 111, 122–123).

As has been before observed, the brilliant investigations of Berzelius and Hisinger, together with those of Nicholson and Carlisle, of Dr. William Henry and of Sir Humphry Davy, actually created a new epoch in the history of chemistry. Prof. Wm. B. Rogers better expressed the fact in his address of Jan. 16, 1879, when saying that “through the labours mainly of Berzelius and of Davy, the great generalization of electro-positive and electro-negative substances was established, and with it the fruitful theory of the electro-chemical exposition of compound bodies.” Such of the experiments of Berzelius as were repeated by Sir Humphry Davy before the English Royal Institution, are embodied in Davy’s paper (partly alluded to above in “Bakerian Lectures”) which was read before the Royal Society, June 30, 1808. According to J. F. W. Herschel, Berzelius and Hisinger ascertained it as a general law, that in all of the chemical decompositions which they effected, the acids and oxygen become transferred to, and accumulated around, the positive pole, and hydrogen, alkaline earths and metals around the negative pole of a voltaic circuit; being transferred in an invisible, and, as it were, a latent or torpid state, by the action of the electric current, through considerable spaces, and even through large quantities of water or other liquid, again to reappear with all their properties at their appropriate resting-places.

Berzelius discovered selenium while examining certain substances found in the acid manufactured at Gripsholm, Sweden. He includes selenium among the metals; but as it is a nonconductor of electricity, also a most imperfect conductor of heat, and as, in other respects, it bears much analogy to sulphur, it is generally placed among the non-metallic combustibles (Brande, “Manual of Chemistry,” London, 1848, Vol. I. p. 435; Berzelius, “Lehrbuch der Chemie,” “Traité,” etc., Paris, 1846, Vol. II. p. 184; “Annales de Chimie et de Physique,” Vol. IX. p. 160; “Annals of Philosophy,” Vol. XIII. p. 401 and Vol. VIII, N.S. p. 104). The important rôle which the high electrical resistance of selenium has in its early days been made to play by Mr. Willoughby Smith, Dr. Werner Siemens and others, is alluded to at pp. 791–794 of Vol. IV supplement to “Ure’s Dict. of Arts,” etc., London, 1878.

For full accounts of Berzelius’ numerous contributions to science, attention is called to the following:

REFERENCES.--“Royal Society Catal. of Sc. Papers,” Vol. I. pp. 330–341; “Gedächtnissrede auf Berzelius ...” Berlin, 1851; G. Forchammer, “J. J. Berzelius,” 1849; Poggendorff, Vol. I. pp. 172–175; “Afhandl. i Fisik. ...”; Jos. Thomas, “Dict. of Biography,” 1870, Vol. I. p. 341; “Report Smiths. Inst.” for 1862, p. 380; “Vetensk. Acad. Handl.”; “La Grande Encyclopédie,” Vol. VI. p. 478. See likewise, “Journal Frankl. Inst.,” 3rd Ser., Vol. XVI. pp. 343–348; Faraday’s “Experim. Researches,” Arts., 746, 870, 960, and Vol. II. pp. 226–228; Gahn at p. 226 of Becquerel’s “Eléments d’El. Ch.,” Paris, 1843; “Annalen der Physik,” Vol. XXVII. pp. 270, 311, 316, and Vol. XXXVI. p. 260; Gehlen’s “Journal für die Chem. und Phys.,” Vol. I. p. 115 and Vol. III. p. 177; John Black, “An Attempt ... Electro-Chem. Theory,” London, 1814; Gmelin’s “Chemistry,” Vol. I. pp. 400, 457–458, 461–462; “Encycl. Metrop.” (Galvanism), Vol. IV. pp. 221–222; “Sc. Am. Suppl.,” No. 284, p. 4523, for report of Helmholtz’s Faraday Lecture of April 5, 1881, taken from the “Chemical News”; Sturgeon’s “Annals,” Vol. VII. pp. 300–303; Vol. VIII. p. 80; Whewell, “History of the Inductive Sciences,” 1859, Vol. II. pp. 304, 347–348; Thos. Thomson, “An Outline of the Sciences ...” London, 1830, Chap. XIV. p. 532; Berzelius and Wöhler on Volcanoes, in Poggendorff’s “Annalen,” Bd. I. s. 221, and Bd. XI. s. 146; “Journal des Savants” for June 1892, pp. 375–385; J. Berzelius and F. Wöhler, Leipzig, 1901; “Svenskt Biografiskt Handlexikon,” Herm. Hofberg, Stockholm, pp. 88–89; “Bibl. Britan.,” Vol. LI, 1812, pp. 174–183 (“Nicholson’s Journal,” July 1812) for John Gough’s remarks on the hygrometer of Berzelius (Phil. Mag., Vol. XXXIII. p. 177); “Annales de Chimie,” Vol. LI. pp. 167, 171; Vol. LXXXVI for 1813, p. 146; Vol. LXXXVII. pp. 286, etc.; also Vol. LXXIII. pp. 198, 200–201, the last named giving an account of the ammoniacal amalgam which Berzelius and Pontin were the first to explain.

=A.D. 1802.=--Thompson (Sir Benjamin), Count Rumford, an eminent scientist, native of Woburn in Massachusetts, Knt., F.R.S., one of the founders of the English Royal Institution, publishes his “Philosophical Memoirs ... being a collection of ... Experimental Investigations ... of Natural Philosophy.”

Though more properly identified with important observations and researches on heat, the question of the nature of which, Dr. Edward L. Youmans says, he was the first to take out of the domain of metaphysics, where it had stood since the days of Aristotle, he has given accounts of some highly important experiments regarding the relative intensities and the chemical properties of light, heat and electricity, which can be seen at pp. 273, etc., Vol. LXXVI. part ii. of the Phil. Trans. for 1786. Heat spreads in every direction, whilst the electrical fluid may be arrested in its progress by certain bodies, which have on that account been called non-conductors, but he shows that the Torricellian vacuum affords, on the contrary, a ready passage to the electrical fluid while being a bad conductor of heat.

At p. 30 of George E. Ellis’ “Memoir of Sir Benjamin Thompson,” published in Boston (no date), is reproduced Rumford’s “Account of what expense I have been at toward getting an electrical machine” during 1771, and at pp. 481–488, Vol. I, also pp. 350, 351, Vol. III of the “Complete Works of Count Rumford,” published by the American Academy of Sciences, allusion is made to the galvanic influence in the construction of utensils.

REFERENCES.--Sir W. Thomson, “Mathematical and Physical Papers,” London, 1890, Vol. III. pp. 123, 124; Phil. Mag., Vol. IX for 1801, p. 315; Silliman’s American Journal of Science, Vol. XXXIII. p. 21; “Biog. Universelle,” Tome XXXVII. p. 81; “Journal des Savants,” for Dec. 1881 and Jan. 1882; “Bibl. Britan.,” Vol. LVI., 1814, pp. 398–401 (necrology).

=A.D. 1802.=--Pepys (William Haseldine, Sr.), son of an English manufacturer of surgical instruments, who became F.R.S. and was one of the founders of the Askesian Society, as well as of both the London Institution and of the London Geological Society, constructs, during the month of February 1802, the strongest pile hitherto known. It consists of sixty pairs of zinc and copper plates, each six feet square, held in two large troughs filled with thirty-two pounds of water containing two pounds of azotic, or nitric, acid.

It is said that with this battery he succeeded in melting iron wires ranging in diameter from one two-hundredth to one-tenth of an inch, the combustion developing an extremely bright light, while platinum wires, one thirty-second of an inch in diameter, turned to white heat and melted in globules at the point of contact. Charcoal was permanently ignited a length of nearly two inches and the galvanic action was strong enough to light it after passing through a circuit of sixteen persons holding one another by the hand. Gold leaf displayed a bright white light, accompanied with smoke; silver leaf gave an intense green light without sparks, but with still more smoke; while sheets of lead burned actively, with accompaniment of very red sparks mixed with the flame (Figuier, “Exposition,” etc., Paris, 1857, Vol. IV. p. 347).

Later on, another battery was constructed by him for the London Institution. This consisted of 400 pairs of plates five inches square, and of 40 pairs one foot square. With it, Davy ignited cotton, sulphur, resin, oil and ether, melted a platinum wire, burned several inches of an iron wire one three-hundredth of an inch in diameter, and boiled easily such liquids as oil and water, even decomposing and transforming them into gases. It was during the year 1808 that Pepys finished the enormous battery of 2000 double plates already alluded to under the Cruikshanks (A.D. 1800) and the Davy (A.D. 1801) articles, and which is to be found described at p. 110 of the “Elements of Chemical Philosophy.”

One year before that (1807) Pepys constructed a new form of eudiometer, of which a description was given before the Royal Society on the 4th of June, as shown at p. 270 Vol. I of the “Abstracts of Papers,” etc., of that Institution, as well as in the 1807 volume of the Philosophical Transactions.

Of the many ingenious experiments by which Pepys distinguished himself, scarcely none attracted more attention than those which are referred to in the last-named Transactions for 1866, pp. 339–439. It is only since 1815, when he employed the electric current to heat iron wire and diamond dust together, whereby he obtained steel, that the direct carburization of iron by the diamond has been clearly established. Prior to this date, during 1798, Clouet had melted a little crucible of iron weighing 57·8 grammes containing a diamond weighing 0·907 gramme, and produced a fused mass of steel. Guyton de Morveau reported upon Clouet’s experiment in the Annales de Chimie for 1799 (Vol. XXXI. p. 328) and his investigations were repeated by many scientists, notably by Margueritte, as recently as 1865. The latter’s observations, which were communicated to the Annales de Chimie et de Physique (Tome VI), showed that, although carburization can be effected by simple contact of carbon and iron in a gaseous atmosphere, it is nevertheless true that in the ordinary process of cementation the carbonic oxide gas plays an important part, which had until then been overlooked (Translation of Prof. W. C. Roberts-Austen, F.R.S. For Mr. Children’s investigations in the same line, see the Phil. Trans. for 1815, p. 370, also A.D. 1809).

Sir Humphry Davy employed in his experiments on the decomposition and composition of the fixed alkalies two mercurial gasometers of Pepys’ design, described in No. 14 of the Phil. Trans. for 1807, in conjunction with the same apparatus used by Messrs. Allen and Pepys for the combustion of the diamond (“Bakerian Lectures,” London, 1840, pp. 84 and 93).

During the year 1822 Pepys constructed for electro-magnetic experiments a very large spiral galvanic battery, which was put together for the London Institution on the plan of the one first built by Dr. Robert Hare, Professor of Chemistry in the University of Pennsylvania. Pepys called it a calorimotor, by reason of its remarkable power of producing heat, and it is well illustrated in the 8th Edit. “Encyclopædia Britannica” article on “Voltaic Electricity.” It consisted only of two metallic sheets, copper and zinc, fifty to sixty feet long by two feet wide, coiled around a cylinder of wood and prevented from coming together by three ropes of horse-hair, the whole being suspended over a tub of acid so that, by a pulley or otherwise, it could be immersed or taken up. As stated in Vol. V of the Trans. of the Amer. Phil. Soc., this battery required nearly fifty-five gallons of fluid, and the solution used contained about one-fortieth of strong nitrous acid.

When, as Noad observes, it is stated that a piece of platinum wire may be heated to redness by a pair of plates only four inches long and two broad, the calorific power of such an arrangement as the above may be imagined to have been immense. The energy of the simple circle depends on the size of the plates, the intensity of the chemical action on the oxidizable metal, the rapidity of its oxidation, and the speedy removal of the oxide. Pouillet is said to have constructed one of these batteries with twelve couples for the Paris Faculté des Sciences, and found it very powerful in producing large quantities of electricity with low tension. The best liquid for this battery was water with one-fortieth in volume of sulphuric acid and one-sixtieth of nitric acid. With the above-described battery of Mr. Pepys, Sir Humphry Davy performed a remarkable experiment which is to be found described in the Phil. Trans. for 1823. A similar apparatus was produced independently, at about the same time, by Dr. Seebeck, of Berlin.

Another of Pepys’ inventions is the substitution, for the tinfoil coatings within the glass of Bennet’s electroscope, of two plates, forming an acute angle, which, by means of a regulating screw, can be adjusted to any required distance from the gold leaves. The angular part is secured to the bottom; the open part perpendicularly upward. By this mode of approximating the coatings to the gold leaves, the resistance being diminished, a weaker intensity of electricity suffices for their disturbance.

REFERENCES.--Quarterly Journal of Science, Vol. I for 1816; Phil. Mag., Vol. XXI. p. 241; XLI. p. 15; Becquerel, Vol. I. p. 34. Mr. William H. Pepys, Jr., published descriptions of the newly invented galvanometer and of the large galvanic apparatus in the Phil. Mag., Vol. X., June 1801, p. 38, and Vol. XV for 1803, p. 94; “Cat. Sc. Papers Roy. Soc.,” Vol. II. p. 192; “Bibl. Britan.,” Vol. XVIII, 1801, p. 343, and Vol. XXII, 1803, p. 297.

=A.D. 1803.=--Geoffroy Saint-Hilaire (Etienne), a very eminent French naturalist, once the pupil of Haüy, whose life he was the means of saving during the massacre of September 1792, is the first to give a thoroughly complete description of the electrical organs and functions of the raia torpedo, of the gymnotus electricus, of the silurus electricus, and of other similar species of fishes. His work on the subject, entitled “Sur l’anatomie comparée,” etc., is alluded to in Vol. I. An. xi. No. 5 of the “Annales du Museum,” whence it is translated for the fifteenth volume of the Phil. Mag.

His analyzation of the fluid in the cells of the torpedo showed it to consist of albumen and gelatine; and he discovered some organs analogous to those of the torpedo in different species of the same genus raia, which, strange to say, do not appear possessed of any electrical power.

The electrical organs of the silurus electricus he found to be much less complicated than those of other electrical fishes. They lie immediately below the skin and stretch all around the body of the animal. Their substance, he says, is a reticulated mass, the meshes of which are plainly visible, and these cells are filled, like those of other electrical fishes, with an albuminous gelatinous matter. The nerves distributed over the electrical organs proceed from the brain, and the two nerves of the eighth pair have a direction and nature peculiar to this species. (Consult C. Matteucci, “Traité des Phénomènes ...” Paris, 1844, Chaps. VI and VII. pp. 301–327.)

In his great work on Egypt (Pl. XII, 2) Geoffroy gives the figure of a malapterus electricus (see Adanson, A.D. 1751) which is opened to show the viscera, but, by a singular inaccuracy, says Mr. James Wilson, the fish is represented as scaly, whereas there are no scales whatever upon this fish, and no fish known to possess electric powers has either scales or spines. The torpedo, the gymnotus and the malapterus have all naked skins. The tetraodon electricus (see Shaw at A.D. 1791) is also destitute of spines on the skin, although all its congeners have skins as bristly as those of a hedgehog.

Geoffroy Saint-Hilaire (Isidore), son of Etienne, was also a distinguished naturalist. He became Assistant Professor of Zoölogy to his father in 1829, likewise his assistant at the Faculté des Sciences in 1837, and, when Etienne became blind, during the year 1841, he succeeded to the Professorship of Zoölogy at the Museum of Natural History. He is the author of “The Life, Works and Theories (Vie, Travaux et Doctrine) of Etienne Geoffroy Saint-Hilaire,” Paris, 1847.

REFERENCES.--Gilbert’s Annalen, XIV. p. 397; Bulletin Soc. Phil., No. 70; Geo. Wilson’s “Life of Cavendish,” London, 1851, p. 469, alluding to the later experiments on electrical fishes made by Faraday (1838), Dr. James Stark, of Edinburgh (1844), Prof. Goodsir (1845), and Dr. C. Robin (1846). Consult also, Journal de Physique, Vol. LVI. p. 242, and the complete list of Geoffroy’s works in Callisen’s “Medicinisches-Schriftsteller Lexicon”; “Memoir of M. Isidore G. Saint Hilaire,” by M. De Quatrefages, in “Report of Smithsonian Institution” for 1872, pp. 384–394; “Journal des Savants” for May-Aug., 1864; “Roy. Soc. Cat. of Sc. Papers,” Vol. II. pp. 824–832; Vol. VI. p. 669; Vol. VII. p. 757.

=A.D. 1803.=--Carpue (J. C. S.), English scientist, relates, in his “Introduction to Electricity and Galvanism,” published in London, some noteworthy experiments on the curative action of common electricity.

He repeated many of the investigations of Giovanni Aldini, and, in the presence of Dr. Pearson and other medical gentlemen, experimented upon the body of Michael Carney, immediately after his execution for murder. Carpue’s main object was to ascertain whether galvanism, applied at once to the nerves, could excite action in the internal parts, and especially in the respiratory organs. He first made an opening into the windpipe and, after introducing about three pints of oxygen into the lungs, he applied conductors to the phrenic nerve as well as to other parts of the body, the lungs being at the same time occasionally inflated, but no action could be excited in the diaphragm. The application of conductors to the inside of the nostrils and elsewhere, however, excited very considerable contractions in the right auricle more than three hours after death, the ventricles being, as in Aldini’s experiments, perfectly motionless.

REFERENCES.--“Galvanic Experiments Made by Carpue on the Body of Michael Carney,” etc., London, 1804 (Phil. Mag., Vol. XVIII. p. 90); the “Encyclopedia Metropolitana,” article “Galvanism,” Vol. IV. pp. 105, 106, also the “Introduction,” etc., above named for descriptions of Mr. Cuthbertson’s plate electrical machine and of Mr. Read’s condenser.

=A.D. 1803.=--Hachette (Jean Nicholas Pierre), a protégé of Monge, who became professor at the Paris Ecole Polytechnique, where he had among his pupils Poisson, Arago and Fresnel, presents to the Institut National the dry pile which was the result of the many experiments he had carried on in conjunction with Charles Bernard Desormes, who was then known as a prominent French scientist and manufacturer of chemical products.

Their idea was to establish the development of electricity by simple contact, and they sought to obtain a substance which would satisfactorily replace the wet discs, and not be affected by the metals, as had been all the liquids hitherto employed (H. Boissier, “Mémoire,” etc., Paris, 1801). After numerous investigations they adopted a compound consisting of common starch and either salts, varnishes or gums, with which they made the necessary discs. These discs were dried and placed alternately between the copper and zinc couples, but were afterward found to be too easily affected by moisture to prove very effective (D. Tommasi, “Traité des Piles Electriques,” Paris, 1889, p. 529).

In the columns of the Annales de Chimie, named below, will be found detailed the numerous experiments with the galvanic pile carried on individually and collectively by Hachette, Desormes and other scientists; those of Hachette and Thénard upon the ignition of metallic wires claiming especial notice. Prof. John Farrar (“Elem. of Elec. Magn.,” etc., Cambridge, 1826, p. 167) calls attention to the latter and in the Phil. Mag. for 1821 will be found an account of the researches of the above-named scientists made during the year 1805, to establish more properly the analogy between galvanism and magnetism. Hachette and Desormes endeavoured to ascertain the direction which would be taken by a voltaic pile, whose poles were not joined, when freely suspended horizontally. Their pile, as Fahie gives it, was composed of 1480 thin plates of copper tinned with zinc, of the diameter of a five-franc piece, and was placed upon a boat floating on the water of a large vat; but it assumed no determinate direction, although a magnetized steel bar, of a weight nearly equal to that of the pile, and likewise placed upon the boat, would turn, after some oscillations, into the magnetic meridian.

REFERENCES.--Annales de Chimie, Vol. XXXVII. pp. 284–321; XLIV. pp. 267–284; XLVII (Biot’s Observations), p. 13; XLIX. pp. 45–54, and XLV for 1808. See also, the Annales for 1834, as well as Vol. XLII. p. 125, for experiments of MM. Desormes and Clement on the fixed alkalies; Journal de Physique of Sept. 1820, for the paper of Hachette and Ampère on the electro-magnetic experiments of Oersted and Ampère; Annales de Chimie et de Physique, Vol. II for May 1816, pp. 76–79, and V. p. 191; Phil Mag., Vol. LVII. p. 43; L. W. Gilbert, Annalen der Physik, Vols. IX. pp. 18–39; XVII. pp. 414–427; Journal de l’Ecole Polytechnique, Vol. IV for 1802; XI. p. 284; Leithead, “Electricity,” p. 252; Bull. de la Soc. Philomathique, No. 83; P. Sue, aîné, “Hist. du Galv.,” Paris, An. X, 1802, Vol. II. pp. 160, 167, 188, 345 (Hachette et Thénard), and p. 371; Joseph Izarn, “Manuel du Galvanisme,” An. XII, 1804, s. 4. p. 179; Poggendorff, Vol. I. pp. 562, 985; Larousse, “Dict. Universel,” Vol. VI. p. 576; “Royal Society Catalogue of Scientific Papers,” Vol. III. pp. 106–109.

=A.D. 1803.=--Biot (Jean Baptiste), who, in 1800, at the age of twenty-six, was made Professor of Natural Philosophy at the “Collège de France,” and afterward ranked among the first astronomers and mathematicians, gives an account of his journey to Aigle, in the Department of l’Orne, whither he was sent by the Government to examine and report upon a very extraordinary shower of meteorites. The facts obtained by him were communicated to the Institute on the 29th Messidor, An. XI, and also appeared at the time in the Paris Journal des Débats (Phil. Mag., Vol. XVI. p. 299).

On the 23rd of August of the year following (1804) Biot accompanied Gay-Lussac in the latter’s first memorable balloon ascent. This aeronautic voyage, sanctioned by the French Government mainly through the efforts of Berthollet and Laplace, was the first of the kind undertaken solely for a scientific object.

Besides numerous barometers and electrometers, Biot and Gay-Lussac carried with them two compasses, a dipping needle and other instruments. For the examination of the electricity of different strata of the atmosphere, they had several metallic wires from 60 to 300 feet in length, also a small electrophorus feebly charged, while for galvanic experiments they added some discs of copper and zinc, together with a supply of frogs, insects and birds. An account of the exceedingly important results obtained by those scientists at different elevations, of which the highest reached exceeded four miles, was read before the National Institute, Aug. 27, 1804. It was also published in London during the latter year, and alluded to at p. 371, Vol. XIX of the Philosophical Magazine. Mary Somerville remarks (“Connection of the Physical Sciences,” 1846, p. 334) that according to the observations of Biot and Gay-Lussac, the magnetic action is not confined to the surface of the earth, but extends into space. The moon has become highly magnetic by induction, in consequence of her proximity to the earth, and because her greatest diameter always points toward it. Her influence on terrestrial magnetism is now ascertained; the magnetism of the hemisphere that is turned toward the earth attracts the pole of our needles that is turned toward the south and increases the magnetism of our hemisphere; and as the magnetic, like the gravitating force, extends through space, the induction of the sun, moon and planets must occasion perpetual variations in the intensity of terrestrial magnetism, by the continual changes in their relative positions.

In 1805 Biot published an investigation of the laws which should govern the dip and intensity, in the hypothesis of a magnet situated at the centre of the earth, having its poles infinitely close to each other and directed to opposite points on the surface of the globe and, as justly adds Major Edward Sabine (Report Seventh Meeting Brit. Asso.), it is a well-known consequence of this hypothesis that the lines of equal dip and equal intensity on the earth’s surface should everywhere be parallel to each other. The phenomena of electricity had been brought within the pale of mixed mathematics by C. A. Coulomb (A.D. 1785), whose considerations mainly attached to the distribution of electricity upon the surface of spheres, and his investigations were at once diligently pursued by the French scientists, Biot, Laplace and Poisson. Laplace, who undertook to investigate the distribution of electricity upon the surface of ellipsoids of revolution, showed that the thickness of the coating of the fluid at the pole was to its thickness at the equator as the equatorial is to the polar diameter, or, what is the same thing, that the repulsive force of the fluid, or its tension at the pole, is to that at the equator as the polar is to the equatorial axis. Biot extended this investigation to all spheroids differing little from a sphere, whatever may be the irregularity of their figure, and his solution of the problem will be found in No. 51 of the Bulletin des Sciences. He also determined, analytically, that the losses of electricity form a geometrical progression when the two surfaces of a jar or plate of coated glass are discharged by successive contacts, and he found that the same law regulated the discharge when a series of jars or plates are placed in communication with each other (Whewell, “History of the Inductive Sciences,” Vol. II. pp. 208, 223; Noad’s “Manual,” p. 15; Eighth “Britannica,” Vol. VIII. p. 531. For Biot’s experiments, touching upon electrical attraction and demonstrating practically the distribution of electricity upon the surface of a conductor, see the last-named volume of the “Britannica,” pp. 552, 556, and Noad, p. 56).

In conjunction with Frederick Cuvier, Mr. Biot investigated the connection of chemical charge with the production of electricity. Like Mr. W. H. Pepys, they examined the effect produced by the pile on the atmosphere in which it is located. Mr. Pepys placed the pile in an atmosphere of oxygen, and found that in the course of a night 200 cubic inches of the gas had been absorbed, but that in an atmosphere of azote the pile ceased to act. Biot and Cuvier likewise observed the quantity of oxygen absorbed, and inferred from their experiments that “although, strictly speaking, the evolution of electricity in the pile was produced by oxidation, the share which this had in producing the effects of the instrument bore no comparison with that which was due to the contact of the metals, the extremity of the series being in communication with the ground.” Their investigation was attended by the discovery that as long as any oxygen remained to be absorbed, the chemical and physiological effects of the apparatus still continued, but with decreasing intensity; so that if the conducting wires attached to the two poles are made to return from under the receiver in tubes of glass they may be used to decompose water and communicate shocks to the organs. All these effects, however, cease when the surrounding oxygen is exhausted (Annales de Chimie, Vol. XXXIX. p. 242; Soc. Philomathique, An. IX. p. 40; Sue, “Histoire du Galv.,” Vol. II. p. 161).

In the second volume of Biot’s “Traité de Physique” will be found recorded his many observations on the nature and origin of the electric light, extracts from which are given by Sir David Brewster in the electricity article of the “Britannica.” Biot remarks that the light which is observed during an electric explosion was for a long time considered by philosophers as a modification of the electric principle itself, which they supposed to be the quality of becoming luminous at a certain degree of accumulation (John Farrar, “Elem. of Elec., Mag. and El. Mag.,” 1826, p. 118). Brewster adds that this eminent French writer, however, considered the opinion as erroneous, and he has devoted a whole chapter to prove that electricity has the same origin as the light disengaged from air by mechanical pressure, “and that it is purely the effect of the compression produced on the air by the explosion of electricity.” In order to establish this theory, Mr. Biot has stated, on the authority of several experiments, “that the intensity of electric light depends always on the ratio which exists between the quantity of electricity transmitted and the resistance of the medium”; and he has shown, by an experiment with Kinnersley’s thermometer, “that at each spark the air of the cylinder, driven by the repulsive force, presses on the surface of mercury, which rises suddenly in the small tube, and falls back again immediately after the explosion.” He adds:

“This indication proves the separation produced between the particles of the mass of air where the electricity passes; and from what we know of its extreme velocity it is certain that the particles exposed immediately to its shock ought in the first moment to sustain individually all the effect of the compression. They ought, then, from this cause alone to disengage light, as when they are subjected to any other mechanical pressure. Thus one part at least of the electric light is necessarily due to this cause; and this being the case, there is no experiment which can lead us to conjecture that it is not all due to this cause.”

REFERENCES.--“Encycl. Brit.,” 1857, Vol. XIV. pp. 7, 63, and Journal de Physique, Vol. LIX. p. 450. For Mr. Biot’s observations on the magnetism of metals and minerals, and on the distribution of magnetism in artificial magnets, as well as for his improvement upon Coulomb’s method of constructing the latter, see the last-named volume of the “Britannica,” pp. 23, 26, 71, and Noad’s “Manual of Electricity,” London, 1859, pp. 528, 535, while, for Biot’s very ingenious theory relative to the aurora, see Lardner and Walker’s “Manual of Elec. Mag. and Meteor.,” London, 1844, Vol. II. p. 235, and Noad, pp. 232, 233. The observations concerning the laws regulating the intensity of electro-magnetic phenomena, made by MM. Biot and Savary, are alluded to by Noad at pp. 644, 645, in the “Encycl. Metropol.” (Elec. Magn.), Vol. IV. p. 427; and Whewell’s “History of the Inductive Sciences,” 1859, Vol. II. pp. 245–249; “Scientific papers of the Royal Society,” Vol. I. pp. 374–386; Biot’s “Traité de Phys. Exp. et Math.,” Vol. II. p. 457; Journal de Physique, Vol. LIX. pp. 315, 318; Wilkinson’s “Elem. of Galv.,” Vol. II. pp. 38, 123, 154, 361, Chap. XVI; Humboldt’s “Cosmos,” treating of Aerolites, of the Zodiacal Light and of the figure of the earth; Noad, “Manual,” p. 530; Eighth “Ency. Brit.,” Vol. VIII. p. 580; Sir H. Davy, “Bakerian Lectures,” London, 1840, p. 3, alluding to Biot and Thénard in No. 40 of the Moniteur for 1806; “Encycl. Metropol.,” Vol. IV. (Electro-Magn.), p. 7; Harris “Rudim. Magn.,” Part III, London, 1852, pp. 116, 117; Gautherot at A.D. 1801; Figuier, “Exposition,” etc., Paris, 1857, Vol. iv. p. 429; “Lib. of Useful Knowl.” (Electricity), p. 64 and (Magnetism), p. 89; “Soc. Philomath.,” An. IX. p. 45; An. XI. pp. 120, 129; Becquerel’s “Traité,” 1856, Vol. III. p. 11; Phil. Mag., Vols. XVI. p. 224; XXI. p. 362; “Mém. de l’Institut” for 1802, Vol. V; “Annales des Mines” for 1820, relative to the experiments on electro-magnetism made by Oersted, Arago, Ampère and Biot; Phil. Mag., Vol. XXII. pp. 248, 249, for the magnetical observations made by Biot and Arago; Comptes Rendus for 1839, I Sem., VIII, No. 7, p. 233, for the observations of Biot and Becquerel on the nature of the radiation emanating from the electric spark; “Chemical News,” London, 1868, Vol. XVI for John Tyndall’s lecture on some experiments of Faraday, Biot and Savary; “Atti dell’ Accad. dei Nuovi Lincei, Ann.,” XV. Sess., IV. del 2 Marzo 1862, for the biography of J. B. Biot, who died Feb. 2, 1862, within two months of the completion of his eighty-eighth year. “Journal des Savants” for June and July 1820, April 1821, and for Feb.-Mar.-April 1846.

J. B. Biot’s son, Edward Constant Biot (1803–1850), is the author of the extended catalogue of shooting stars and other meteors observed in China during twenty-four centuries, which was presented to the French Academy during 1841, and a supplement to which was published at Paris in 1848 (Acad. des Sciences, Savants Etrangers, Tome X).

=A.D. 1803–1805.=--Acting upon the discovery of Gautherot, the Bavarian philosopher Johann Wilhelm Ritter (1776–1810) is the first to construct an electrical accumulator.

Ritter’s “ardency of research and originality of invention” had, as far back as 1796, shown itself in the numerous very able scientific papers relating to Electricity, Galvanism and Magnetism which he had communicated mainly through L. W. Gilbert’s Annalen der Physik, J. H. Voigt’s Mag. für Naturkunde and A. F. Gehlen’s Journal für die Chemie, all which obtained recognition in several foreign publications. These papers secured for him membership in the Munich Academy during the year 1805.

From Prof. H. W. Dove’s discourse before the Society for Scientific Lectures, of Berlin, the following is extracted:

“As the (then considered) essential portions of a galvanic circuit were two metals and a fluid, innumerable combinations were possible, from which the most suitable had to be chosen. This gigantic task was undertaken by Ritter, an inhabitant of a village near Leignitz, who almost sacrificed his senses to the investigation. He discovered the peculiar pile which bears his name, and opened that wonderful circle of actions and reactions which, through the subsequent discoveries of Oersted, Faraday, Seebeck and Peltier, drew with ever-tightening band the isolated forces of nature into an organic whole. But he died early, as Günther did before him, exhausted by restless labour, sorrow and disordered living.”

Ritter’s charging or secondary pile consists of but one metal, the discs of which are separated by circular pieces of cloth, flannel or cardboard, moistened in a liquid which cannot chemically affect the metal. When the extremities are put in communication with the poles of an ordinary voltaic pile it becomes electrified and can be substituted for the latter; and it will retain the charge, so that for a time there can be obtained from it sparks, shocks, as well as the decomposition of water.

The writer of the article at p. 268 of the April 1802 Monthly Magazine, making reference to an artificial magnet discovered at Vienna (Bakewell, “Elec. Science,” p. 40), no doubt alludes to the above-named charging or secondary pile, in the construction of which Ritter made many modifications. At first he arranged 32 copper and card discs in three series, two of which series contained 16 copper discs while the intermediate series consisted of 32 card discs. He then placed them so that the discs alternated, employing but 31 discs of copper, and he also used 64 as well as 128 copper discs alternating with similar ones of cardboard. In each case he compared the chemical action through the decomposition of water as well as the physiological effect or shock and the physical property or electrical tension. The results obtained are given in his many papers alluded to below.

Independently of the English scientists he discovered the property possessed by the voltaic pile of decomposing water as well as saline compounds, and of collecting oxygen and acids at the positive pole while hydrogen and the bases collect at the negative pole. He conceived that he had procured oxygen from water without hydrogen, by making sulphuric acid the medium of the communication at the negative surface, but, as Davy says, in this case sulphur is deposited, while the oxygen from the acid and the hydrogen from the water are respectively repelled, and the new combination produced.

A correspondent in Alex. Tilloch’s Philosophical Magazine (Vol. XXIII for 1805–1806, pp. 51–54--Extracts from a letter of M. Christ. Bernoulli abridged from Van Mons’ Journal, Vol. VI) thus alludes to some of Ritter’s experiments communicated in May 1805 to the Munich Royal Society:

“I have seen him galvanize a louis d’or. He places it between two pieces of pasteboard thoroughly wetted, and keeps it six or eight minutes in the circuit of the pile. Thus it becomes charged, though not immediately in contact with the conducting wires. If applied to the recently bared crural nerves of a frog the usual contractions ensue. I put a louis d’or thus galvanized into my pocket, and Ritter told me, some minutes after, that I might discover it from the rest by trying them in succession upon the frog. I made the trial, and actually distinguished, among several others, one in which only the exciting quality was evident. The charge is retained in proportion to the time that the coin has been in the circuit of the pile. Thus, of three different coins, which Ritter charged in my presence, none lost its charge under five minutes. A metal thus retaining the galvanic charge, though touched by the hand and other metals, shows that this communication of galvanic virtue has more affinity with magnetism than with electricity, and assigns to the galvanic fluid an intermediate rank between the two. Ritter can, in the way I have just described, charge at once any number of pieces. It is only necessary that the two extreme pieces of the number communicate with the pile through the intervention of wet pasteboards. It is with metallic discs charged in this manner and placed upon one another, with pieces of wet pasteboard alternately interposed, that he constructs his charging pile, which ought, in remembrance of its inventor, to be called the Ritterian pile. The construction of this pile shows that each metal galvanized in this way acquires polarity, as the needle does when touched with a magnet.”

The same correspondent alludes to experiments made with Ritter’s battery of 100 pairs of metallic plates, the latter having their edges turned up so as “to prevent the liquid pressed out from flowing away” (Phil. Mag., Vol. XXIII. p. 51), but he says he was unable to see either Ritter’s great battery of 2000 pieces, or the one of 50 pieces, each 36 inches square, the action of which is said to have continued very perceptibly for a fortnight. He writes as follows:

“After showing me his experiments on the different contractibility of various muscles (“Beiträge zur nähern Kenntniss,” etc., Jena, 1802, B. II) Ritter made me observe that the piece of gold galvanized by communication with the pile exerts at once the action of two metals, or of one voltaic couple, and that the face which in the voltaic circuit was next the negative pole became positive, and the face toward the positive pole negative. Having discovered a way to galvanize metals, as iron is rendered magnetic, and having found that the galvanized metals always exhibit two poles as the magnetized needle does, Ritter suspended a galvanized gold needle on a pivot, and perceived that it had a certain dip and variation, or deflection, and that the angle of deviation was always the same in all his experiments. It differed, however, from that of the magnetic needle, and it was the positive pole that always dipped.”

It can truly be said that the nearest approach to a solution of the question as to the analogy between electric and magnetic forces, which had remained unsettled since the time of Van Swinden (see A.D. 1784), was given by Ritter, who announced “that a needle composed of silver and zinc arranged itself in the magnetic meridian and was slightly attracted and repelled by the poles of a magnet; that by placing a gold coin in the voltaic circuit, he had succeeded in giving to it positive and negative electric poles; that the polarity so communicated was retained by the gold after it had been in contact with other metals, and appeared therefore to partake of the nature of magnetism; that a gold needle under similar circumstances acquired still more decided magnetic properties; that a metallic wire, after being exposed to the voltaic current, took a direction N.E. and S.W.” Dr. Roget gives these same extracts in his article on “Electro-Magnetism,” and justly remarks that Ritter’s speculations were of too crude a nature to throw any distinct light on the true connection between magnetism and electricity, nor was much notice taken of Ritter’s announcements, owing to the vague manner in which they were made. No satisfactory results were in fact obtained until Oersted (at A.D. 1820) made his famous discovery which forms the basis of the science of electro-magnetism.

REFERENCES.--The “Encyclopædia Britannica” article relating to the influence of magnetism on chemical action, for an account of Ritter’s other experiments; also Faraday’s “Experimental Researches,” No. 1033; Ritter’s “Physisch. Chem. Abhand.,” etc., 3 vols., Leipzig, 1806; Poggendorff, Vol. II. p. 652; Tyndall’s notes on Electric Polarization; Donovan’s “Essay on the Origin, Progress and Present State of Galvanism,” Dublin, 1816; “Société Philomathique,” An. IV. p. 181; An. IX. p. 39; An. XI. pp. 128, 197; An. XII. p. 145; Bull. Soc. Phil., Nos. 53, 76, 79; Nuova Scelta d’Opus., Vol. I. pp. 201, 334; Bibl. Brit., XXXI; “Reichsanzeiger,” 1802, Bd. I, No. 66, and Bd. II, No. 194; also F. L. Augustin’s “Versuch einer geschichte ...” 1803, p. 75; Gilbert’s Annalen, II, VI, VII, VIII, IX, XIII, XV, XVI; Voigt’s Magazin, Vol. II. p. 356; Gehlen’s Journal, Vol. III for 1804, and Vol. VI for 1806; “Denkschr. d. Münch.,” 1808 and 1814; Phil. Mag., Vol. XXIII. chap. ix. pp. 54, 55 (for experiments from Van Mons’ Journal, No. 17), Vols. XXIV. p. 186; XXV. p. 368; LVIII. p. 43; L. F. F. Crell, “Chemische Annalen” for 1801; Nicholson’s Journal, Vols. IV. p. 511; VI. p. 223; VII. p. 288, VIII. pp. 176, 184; “Gottling’s Almanach” for 1801; Leithead, “Electricity,” p. 255; “Encycl. Metropolitana,” article “Galvanism,” Vol. IV. p. 206; “Biographie Générale,” Vol. XLII. p. 322; Larousse, “Dict. Universel,” Vol. XIII. p. 1234; Pierre Sue, aîné, “Histoire du Galvanisme,” Paris, An. X, 1802, Vol. I. pp. 226, 266; Vol. II. pp. 112–119, 156; Joseph Izarn, “Manuel du Galvanisme,” Paris, An. XII, 1804, pp. 84–87, 249, 255–261; Brugnatelli, “Notizie ... nell’ anno 1804,” Pavia, 1805, p. 16, also his Annali di chimica, Vol. XXII. p. 1; Journal de Physique, Vol. LVII. pp. 345, 406; Annales de Chimie, Vols. XLI. p. 208; LXIV. pp. 64–80; Jour. de Chim. de Van Mons, No. 14, p. 212, for the experiments of Van Marum and Oersted, made with Ritter’s apparatus; Sturgeon’s “Scientific Researches,” Bury, 1850, pp. 7, 8, and Prof. Millin’s “Magazin Encyclopédique”; “Allgemeine Deutsche Biographie,” Leipzig, 1875, Vol. XXVIII. pp. 675–678; “Bibl. Britan.,” Vol. XXXI. 1806, p. 97, Vol. XXV. 1807, pp. 364–386 (Lettre de M. le Dr. Thouvenel).

=A.D. 1803.=--Basse (Frédéric Henri), of Hamel, makes one of the earliest trials of the transmission of galvanism through water and soil, the results of which appear in his work, “Galvanische Versuche,” etc., published at Leipzig the year following.

Along the frozen water of the ditch or moat surrounding the town of Hamel he suspended, on fir posts, 500 feet of wire, at a height of six feet above the surface of the ice, then making two holes in the ice and dipping into them the ends of the wire, in the circuit of which were included a galvanic battery and a suitable electroscope, he found the current circulating freely. Similar experiments were made in the Weser; afterwards, with two wells, 21 feet deep and 200 feet apart; and, lastly, across a meadow 3000 to 4000 feet wide. Whenever the ground was dry it was only necessary to wet it in order to feel a shock sent through an insulated wire from the distant battery. Erman, of Berlin, in 1803, and Sömmering, of Munich, in 1811, performed like experiments, the one in the water of the Havel, near Potsdam, and the other along the river Isar.

Fahie, from whom we take the above, alludes to Gilbert’s Annalen der Physik, Vol. XIV. pp. 26 and 385, as well as to Hamel’s “Historical Account,” p. 17, of Cooke’s reprint, and adds that Fechner, of Leipzig, after referring to Basse’s and Erman’s experiments in his “Lehrbuch des Galvanismus,” p. 268, goes on to explain the conductibility of the earth in accordance with Ohm’s law. As he immediately after alludes to the proposals for electric telegraphs, he has sometimes been credited with the knowledge of the fact that the earth could be used to complete the circuit in such cases. This, however, is not so, as we learn from a letter which Fechner addressed to Prof. Zetzsche, on the 19th of February 1872.

REFERENCES.--Zetzsche’s “Geschichte der Elektrischen Telegraphie,” p. 19. See Dr. Turnbull’s Lectures in the Journal of the Franklin Institute, Vol. XXI. pp. 273–274; “Scientific Papers of the Royal Society,” Vol. I. p. 203.

=A.D. 1803.=--Thillaye-Platel (Antoine), French savant, who was afterward appointed pharmacist in the Paris Hôtel-Dieu, gives out as the result of numerous investigations a great many useful precepts on the medical application of electricity and galvanism, which will be found in his thesis presented to the Paris Ecole de Médecine on the 15th Floréal, An. XI. These precepts, De la Rive says (“Treatise on Elect.,” translated by C. V. Walker, London, 1858, Vol. III. pp. 587, 588), are followed to this day and are extremely simple, requiring only the use of metallic brushes held by an insulated handle and put into communication with the conductor of the machine; and directing the application of electricity in its mildest form as well as its gradual increase to as much as the invalid is able to support, besides allowing of the concurrent employment of other means acting in the same direction, such as frictions, blisters, etc.

Antoine Thillaye-Platel’s uncle, Jean Baptiste Jacques Thillaye (1752–1822), French physician and Professor of Anatomy at Rouen and in Paris, published “Eléments de l’Elect. et du Galv.,” Paris, 1816–1817, ten years after the death of his nephew (Poggendorff, Vol. II. p. 1094; Larousse, “Dict. Univ.,” Vol. XV. p. 131).

De la Rive alludes to cures effected by several specialists and particularly to Father R. B. Fabre-Palaprat’s translation made in 1828 of La Beaume’s English work on the medical efficacy of electricity and galvanism, originally published in 1820–1826. The latter, he says, is preceded by a preface wherein the translator rivals the author on the wonderful effects of the electric fluid as a sovereign remedy for nearly all maladies.

REFERENCES.--For M. Thillaye’s experiments with M. Butet on galvanic electricity, made at the Paris École de Médecine, see the Bulletin des Sciences de la Soc. Philom., No. 43, Vendémiaire An. IX, also Vol. IX. p. 231, of the “Recueil Périodique de la Soc. Libre de Médecine du Louvre.” Consult likewise, Poggendorff, Vol. II. p. 1094; “Royal Society Catalogue of Scientific Papers,” Vol. V. p. 954; De la Rive’s “Treatise,” Vol. III. pp. 587, 588; P. Sue, aîné, “Histoire du Galvanisme,” Vol. III. p. 14. Some of the other authors who have treated of the same subject are: F. Zwinger, 1697–1707; W. B. Nebel, 1719; Oppermanno, 1746; E. Sguario, 1746; G. C. Pivati, 1747–1750; G. Veratti, 1748–1750; O. de Villeneuve, 1748; L. Jallabert, 1748–1750; G. F. Bianchini, 1749; Mellarde, of Turin, 1749; Palma, 1749; F. Sauvages de la Croix, 1749–1760; J. B. Bohadsch, 1751; O. M. Pagani, 1751; S. T. Quellmaz, 1753; A. von Haller, 1753–1757; Linné (Linnæus), 1754; P. Paulsohn, 1754; E. F. Runeberg, 1757; P. Brydone, 1757; Lower, 1760; De Lassone, 1763; Wm. Watson, 1763; G. F. Hjotberg, 1765; J. G. Teske, 1765; P. A. Marrherr, 1766; Gardane, 1768–1778; J. G. Krunitz, 1769; R. Symes, 1771; Sigaud de la Fond, 1771; C. A. Gerhard, 1772; Abbé Sans, 1772–1778; J. Janin de Combe Blanche, 1773; J. B. Becket, 1773; Marrigues à Montfort L’Amaury, 1773; G. F. Gardini, 1774; J. G. Schaffer, 1776; Mauduyt, 1776–1786; De Thouri, 1777; A. A. Senft, 1778; Masars de Cazéles, 1780–1788; P. F. Nicolas, 1782; Bonnefoy, 1782; Niccolas, 1783; K. G. Kuhn, 1783, 1797; C. W. Hufeland, 1783; Cosnier, Maloet, Darcet, etc., 1783; J. P. Marat, 1784; G. Vivenzio, 1784; Carmoy, 1784–1785; G. Piccinelli, 1785; L. E. de Tressan, “Essai ...” 1786, p. 233, etc.; Krunitz-Kirtz, 1787; Porna and Arnaud, 1787; F. Lowndes, 1787–1791; J. H. D. Petetin, 1787, 1808; G. Pickel, 1788; Van Troostwijk and Krayenhoff, 1788; R. W. D. Thorp, 1790; G. Wilkinson, 1792; C. H. Pfaff, 1793; G. Klein, 1794; M. Imhof, 1796; C. H. Wilkinson, 1799; C. A. Struve, 1802; Maurice, 1810; J. Morgan, 1815; Le Blanc, 1819; P. A. Pascalis, 1819; J. Price, 1821; K. Sundelin, 1822; Girardin, 1823; Ch. Bew, 1824; Sarlandière, 1825; S. G. Marianini, 1833; F. Puccinotti, 1834; François Magendie, 1836, 1837; Gourdon, 1838; C. Matteucci, Piria, etc., 1838, 1858; Breton Frères, 1844; B. Mojon, Jr., 1845; J. E. Riadore, 1845; A. Restelli, 1846; Budge, 1846; F. Hollick, 1847; R. Froriep, 1850; C. V. Rauch, 1851; H. Valerius, 1852; Burci, 1852; Marie-Davy, 1852–1853; W. Gull, 1852; C. Beckensteiner, 1852–1870; F. Channing, 1852; F. F. Videt, 1853; R. M. Lawrance, 1853–1858; G. M. Cavalleri, 1854, 1857; Briand, 1854; M. Kierski, 1854; P. Zetzell, 1856; Ad. Becquerel, 1856–1860; E. Pfluger, 1856, 1858; Pulvermacher, 1856; P. C. Pinson, 1857; H. Ziemssen, 1857–1866; Philipeaux, 1857; J. Dropsy, 1857; M. Meyer, 1857–1869; Nivelet, 1860–1863; A. Tripier, 1861; J. Rosenthal, 1862; Desparquets, 1862; M. P. Poggioli (Mémoire lu à l’Institut, Oct. 31, 1853; “Annual of Scientific Disc.,” 1865, p. 327); G. Niamias, “Della elettr. ... medicina,” 1851 (“An. of Sci. Disc.,” 1865, p. 327); A. C. Garrat, 1866; H. Lobb, 1867; Aug. Beer, 1868; H. M. Collis (“An. of Sci. Dis.,” 1869, p. 175); Toutain, 1870; J. R. Reynolds, 1872; Onimus and Legros, 1872; as well as Jobert de Lamballe, Richter and Erdmon, T. Guitard, J. J. Hemmer, H. van Holsbeek, T. Percival, J. D. Reuss and Mr. Ware (in Kuhn, Hist. II. p. 183).

=A.D. 1803.=--Berthollet (Claude Louis de), very eminent French scientist, who was the first of the leading chemists to openly endorse the antiphlogistic doctrine propounded by Lavoisier (A.D. 1781), and who with Laplace founded the well-known scientific Société d’Arcueil, admits in his “Essai de Statique Chimique” the analogy existing between caloric and the electric fluid. He believes that the latter during the oxidation of metals does not give out much heat, but causes only a dilatation of bodies which separates their molecules, and he also believes that electricity aids metallic oxidation by lessening cohesion (Delaunay, “Manuel de l’Electricité,” p. 16).

When Berthollet and Charles passed heavy electrical charges through platinum wire, they observed that the latter acquired a temperature about equal to that of boiling water, and therefore not sufficient to fuse the wire. If the metal is one easily oxidized, the separation of the molecules causes them to unite with the oxygen of the air, and it is therefore the oxidation itself which produces the consequent high degree of heat.

REFERENCES.--“Essai de Statique,” Vol. I. pp. 209 and 263. See also “Biographie Générale,” Vol. V. p. 716; Young’s “Lectures,” London, 1807, Vol. II. p. 423, and Nicholson’s Journal, Vol. VIII. p. 80; Larousse, “Dict. Univ.,” Vol. II. p. 617; “Sci. Papers of Roy. Soc.,” Vol. I. pp. 321–323; Sir H. Davy, “Bakerian Lectures,” London 1840, pp. 41, 94, regarding more particularly Berthollet’s elaborate experiments on the decomposition of ammonia by electricity alluded to in Mém. de l’Acad., 1782, p. 324, also Delaunay, “Manuel,” pp. 17, 150.

=A.D. 1804.=--Jacotot (Pierre), Professor of Astronomy at the Lyceum of Dijon, states, at p. 223, Vol. I of his “Eléments de Physique Expérimentale,” that Wlik, teacher of natural philosophy at Stockholm, invented the electrophorus during the year 1762. Jacotot, of course, refers to Johannes Carolus Wilcke (see A.D. 1757) who, during the month of August 1762, constructed a resinous apparatus to which he gave the name of perpetual electrophorus (Scripta Academiæ Suec., 1762). Books V, VI and VII of the same volume treat respectively of Electricity, Galvanism and Magnetism.

REFERENCES.--With regard to the perpetual electrophorus, see L. S. Jacquet de Malzet “Lettre d’un Abbé de Vienne ...” Vienna, 1775, translated into German by “A. H.” (A. Hildebrand), Wien, 1776; also C. Cuyper’s “Exposé d’une méthode ...” La Haye, 1778; and, for other improvements, Marsiglio Landriani, Scelta d’Opuscoli, 12mo, XIX. p. 73; J. F. Klinkosch, _Mém. de l’Acad. de Prague_, III. p. 218. Consult J. C. Poggendorff, “Biog.-Litter. Hand. ...” Vol. I. pp. 1, 182, and Larousse, “Dictionnaire Universel,” Vol. IX. p. 868.

=A.D. 1804.=--Hatchett (Charles), F.R.S. and foreign member of the Paris Academy, communicates through a paper entitled “An Analysis of the Magnetical Pyrites ...” his conclusions that iron must be combined with a large portion of either carbon, phosphorus or sulphur in order to acquire the property of receiving permanent magnetic virtue, there being, however, a limit beyond which an excess of either of the above-named substances renders the compound wholly incapable of exhibiting the magnetic energy. In this connection, the interesting observations of Messrs. Seebeck, Chenevix and Dr. Matt. Young on anti-magnetic bodies, in Vol. XIV. p. 27, of the eighth “Encyclopædia Britannica,” will repay perusal.

Three years before, on the 26th of November 1801, Mr. Hatchett had communicated to the Royal Society an interesting paper on columbium, a new metallic substance found in an ore from the State of Massachusetts.

REFERENCES.--“Abstracts of the papers ... of the _Phil. Trans._,” Vol. I. p. 155; also the Phil. Trans. for 1804, p. 315; Phil. Mag., Vol. XXI. pp. 133 and 213; Poggendorff, Vol. I. p. 1031; “Cat. Sc. Papers Roy. Soc.,” Vol. I. p. 155.

=A.D. 1804.=--M. Dyckhoff publishes in Nicholson’s Journal, Vol. VII. pp. 303 and 305, “Experiments on the activity of a galvanic pile in which thin strata of air are substituted instead of the wet bodies.” His description of what has by many been called the first practical dry pile is as follows:

“I constructed a pile with discs of copper and zinc, and little bits of thin green glass about the size of a lentil, three of which I placed triangularly in the intervals that separated the metallic plates. Thus between each pair of metals I had a thin stratum of air instead of a wet substance. A pile of ten pairs tried by the condenser affected the electrometer as powerfully as a common (voltaic) pile of five pairs.”

It was in the year following, 1805, that Wilhelm Behrends, of Frankfort, constructed his dry pile consisting of eighty pairs of discs of copper, zinc and gilt paper (De la Rive, “Treatise on Electricity,” Vol. II. p. 852).

The investigations of Maréchaux, De Luc, Zamboni and others in the same line will appear in due course.

REFERENCES.--Young’s “Lectures,” London, 1807, Vol. II. p. 430, and Nicholson’s Journal, Vol. VII. pp. 303 and 305, Becquerel, Paris, 1851, p. 34; Sturgeon’s “Lectures on Galvanism,” p. 73; Sturgeon’s Annals of Electricity, Vol. VIII. pp. 378, etc.; Journal de Chimie de Van Mons, No. 11, p. 190, and also No. 12, p. 300, for Bouvier de Jodoigne’s experiments; “Catalogue Scientific Papers of the Royal Society,” Vol. II. p. 432; Gilbert, XIX. pp. 355–360, and Wilkinson’s denial of the effectiveness of Dyckhoff’s pile, in Nicholson’s Journal, Vol. VIII. p. 1.

=A.D. 1804.=--Gay-Lussac (Joseph Louis), one of the most prominent of modern scientists, who was for a time assistant to Berthollet, makes, in Paris, two ascents in a balloon, at heights varying between 12,000 and 23,623 feet, for the purpose of carrying out extensive observations upon terrestrial magnetism. The latter are recorded at length in the Journal de Physique, Vol. LIX, and are alluded to in the articles “Aeronautics” and “Meteorology” of the “Encycl. Brit.,” likewise at Biot, A.D. 1803, and in paragraphs 2961 and 2962 of Faraday’s “Experimental Researches in Electricity,” while at p. 193, Vol. XXI of the Phil. Mag. will be found the account of a very interesting aerial voyage made during January of the same year (1804) by M. Sacharof, of the St. Petersburg Academy of Sciences.

In conjunction with Louis Jacques Thénard (alluded to at Fourcroy, A.D. 1801), Gay-Lussac communicates to the Annales de Chimie for 1810 (Vol. LXXIII. p. 197, etc.), a paper relative to their “preparation of an ammoniacal amalgam through the agency of the voltaic pile” which had been read at the “Institut National” during the month of September 1809, and which is also alluded to at pp. 250, etc., of the Annales de Chimie, Vol. LXXVIII for 1811. Their united “physico-chemical researches on the voltaic pile ...” are reviewed at pp. 243, etc., of the last-named volume and are likewise alluded to at p. 36 of Vol. LXXIX for the same year. The largest of the many piles they employed in their several experiments consisted of 600 pairs with a square surface of 1800 feet (Figuier, “Exposition et Histoire ...” 1857, Vol. IV. pp. 387 and 433; Journal des Mines, Vol. XXX. pp. 5–56; Schweigger’s Journal, Vol. II. pp. 409–423).

At pp. 76, etc., of the second volume of the Annales de Chimie et de Physique for the month of May 1816, are to be found the observations of Gay-Lussac on dry voltaic piles, especially upon those of Desormes et Hachette, De Luc and Zamboni. He remarks that the last named does not appear to have so constructed his pile as to enable the oscillations of the needle to indicate an exact measure of time (Schweigger’s Journal für Chemie, Vol. XV. pp. 113, 130–132), but that the so-called electric clocks of M. Ramis, of Munich, and of M. Streizig, of Verona, readily pointed the hours, minutes and seconds (Schweigger’s Journal, Vol. XIII. p. 379; Ronalds’ “Catalogue” for notices of his own as well as of the clocks of Ramis and of Streizig).

The investigations of Gay-Lussac and Humboldt, relative to the magnetic intensity and dip or inclination, throughout France, Germany, Switzerland and Italy, will be found recorded in the first volume of Mém. d’Arcueil, 1807, while at p. 284, Vol. X, and at pp. 305–309 of the Annales de Chimie are observations of Gay-Lussac and Arago, and at p. 509 of the fourth volume of Figuier’s “Exposition et Histoire,” etc., Paris, 1857, appears an extended account of the special report upon lightning rods, which Gay-Lussac was authorized by the Natural Philosophy Division of the French Academy of Sciences to prepare during the year 1823, and the outcome of which appears in the Comptes Rendus des Séances ... Vol. XXXIX. p. 1142.

REFERENCES.--Faraday’s “Experimental Researches,” 1839, Vol. I. p. 217, note, as well as paragraph No. 741 “Recherches Physicochimiques,” p. 12, and J. Farrar’s “Elem. of Elec. Mag.,” 1826, pp. 150–152; while for Gay-Lussac and Thénard’s repetition of Sir Humphry Davy’s experiments on the decomposition of the alkalies, see Phil. Mag., Vol. XXXII. p. 88; “Instruction sur les parat ...” for Gay-Lussac, Fresnel, Lefevre, Gineau and others, Paris, 1824, and for Gay-Lussac and Pouillet, Paris, 1855. Other reports on lightning rods not hitherto specially mentioned are: J. Langenbucher, 1783; Beyer, 1806–1809; P. Beltrami, 1823; Bourges, at Bordeaux, 1837; Boudin, 1855, and J. Bushee, Amer. Assoc., 1868. The observations of Thénard and Dulong are recorded at paragraphs 609, 612, 636, 637 of Faraday’s “Experimental Researches,” as well as at Vols. XXIII. p. 440; XXIV. pp. 380, 383 and 386 of the Annales de Chimie, and those of Thénard, Fourcroy, and Vauquelin will be found in the Mém. des Soc. Sav. et Lit., Vol. I. p. 204. See “Royal Society Catalogue of Sc. Papers,” Vol. II. pp. 800–807; Vol. V. pp. 944–948; Vol. VI. p. 666; Vol. VII. p. 748; Vol. VIII. p. 1072; “Discours de M. Becquerel ...” Inst. Nat. Acad. des Sciences; Phil. Mag., Vols. XX. p. 83; XXI. p. 220; Sci. Am. Supp., p. 11794; Edin. Magazine, Vol. V. p. 471; Annales de Chimie et Physique for 1818, Vol. VIII. pp. 68, 161, 163; the eighth “Britannica,” Vol. VIII. pp. 532, 539, 573 for Gay-Lussac’s additional experiments; the ninth “Britannica,” Vol. X. pp. 122, etc.; also Report Brit. Asso., London, 1838, pp. 7–8, for the magnetic observations of Gay-Lussac and Humboldt on the European Continent, likewise Sir Humphry Davy “Bakerian Lectures,” London, 1840, pp. 134–137; Humboldt, at A.D. 1799, and Cruikshanks, at A.D. 1800. For a description of the Volta eudiometer invented by Gay-Lussac, see Ann. de Ch. et Phys., Vol. IV. p. 188, also Dr. Hare in Silliman’s Journal, Vol. II. p. 312, and for the “Memoir of Louis Jacques Thénard,” by M. Flourens, see the “Report of the Smithsonian Institution” for 1862, pp. 372–383; “Journal des Savants” for Dec. 1850; Meyer’s “Konversations-Lexikon” Leipzig und Wien, 1894, Vol. VII. pp. 140–141; “Dict. Général de Biog. et d’Histoire,” Paris, 2nd ed., pp. 1218–1219.

=A.D. 1805.=--Mr. Joseph Davis submits to the London Society of Arts an improvement upon the telegraph of Lord George Murray (A.D. 1795), consisting of the addition of a seventh shutter, which, instead of being poised on a horizontal axis, is made to slide up and down in grooves in the centre of the framework; so that it may either range with the six shutters or, if not required at all, may descend into a space provided for it in the roof of the Observatory. By this simple device the power of the apparatus is quadrupled, it being made capable of indicating in all 252 changes.

The night signals are given by a coloured lamp mounted in the centre of the seventh or sliding shutter and by six white lights fastened to the outside of the frame, to produce, through their display or concealment by slides, the same signals as, under ordinary circumstances, are given by the opening and closing of the shutters.

=A.D. 1805.=--Grotthus--Grothuss--(Theodor--more properly Christian Johann Dietrich, Baron von) makes known his theory of electro-chemical decompositions, through the “Mémoire,” etc., published in 12mo at Rome, and of which an English translation appeared in London during 1806.

As Lardner and Fahie have it, Grotthus’ theory was the most plausible of the many proposed at this early period of experimental inquiry to explain chemical decomposition by the voltaic apparatus. The above-named “Mémoire ...” which appeared in the Phil. Mag. for 1806, Vol. XXV. pp. 330–334, is analyzed by both of these writers (Lardner, “Electricity, Mag. and Meteor.,” Vol. I. pp. 135–137, or “Popular Lectures,” 1851, Vol. I. pp. 348, 349; Fahie, “Hist. of Elec. Teleg.,” pp. 210, 211), but it may be briefly stated in the words of Sir David Brewster as follows:

“Grotthus (Annales de Chimie for 1806, Vol. LVIII. p. 61) regards the pile as an electric magnet with attracting and repelling poles, the one attracting hydrogen and repelling oxygen, and the other attracting oxygen and repelling hydrogen. The force exerted upon each molecule of the body is supposed to be inversely as its distance from the poles, and a succession of decompositions and recompositions is supposed to exist among the intervening molecules.”

In this connection it will be well to add here, by way of contrast, and again according to Sir David Brewster, the views held by other experimentalists of the same period. Sir Humphry Davy adopts the idea of attractions at the poles, diminishing to the middle or neutral points, and he thinks a succession of decompositions and recompositions probable. Messrs. Riffault and Chompré regard the negative current as collecting and carrying the acids on to the positive pole, and the positive current as doing the same, with the bases toward the negative pole. Biot attributes the effects to the opposite electrical states of the decomposing substances in the vicinity of the two poles. M. De la Rive considers the portions decomposed to be those contiguous to both poles, the current from the positive pole combining with the hydrogen or the bases which are there present, and leaving the oxygen or acids at liberty, but carrying the substances in union with it across to the negative pole, where it is separated from them, entering the conducting metal, and leaving on its surface the hydrogen or its bases. Faraday regards the poles as exercising no specific action, but merely as surfaces or doors by which the electricity enters into or passes out of the substance undergoing decomposition. He supposes that “the effects are due to a modification of the electric current and the chemical affinity of the particles through or by which that current is passing, giving them the power of acting more forcibly in one direction than in another, and consequently making them travel by a series of successive decompositions and recompositions in opposite directions, and finally causing their repulsion or exclusion at the boundaries of the body under decomposition in the direction of the current, and that, in larger or smaller quantities, according as the current is more or less powerful.”

In 1810 Grotthus published his “Uber d. elektricität ... wassers entwickelt,” one of his curious observations being the fact that when water is rapidly frozen in a Leyden jar, the outside coating, not being insulated, receives a weak electrical discharge, the inside being positive and the outside negative, and when the ice is rapidly thawed, the inside is negative and the outside positive.

REFERENCES.--Faraday’s “Experimental Researches,” articles 481, 485, 489, 492, 507, etc.; also Phil. Mag., Vols. XXIV. p. 183, and XXVIII. pp. 35 and 59; Joseph Izarn, “Manuel du Galvanisme,” pp. 280–284 for M. Riffault and N. M. Chompré; Whewell, “History of the Inductive Sciences,” Vol. II. p. 304; Noad, “Manual,” pp. 364, 365; William R. Grove, “On Grotthus’ Theory ...” London, 1845; J. S. C. Schweigger’s Journal, Vols. III, IV, IX, XXVIII and XXXI; A. F. Gehlen’s Journal for 1808; L. W. Gilbert’s Annalen der Physik, Vol. LXVII; Ostwald, “Elektrochemie,” 1896, pp. 309–316; A. N. Scherer’s Allgem. nördliche Annal. d. Chemie, Vol. IV; Annales de Chimie, Vol. LXIII; Phil. Mag., Vol. LIX. p. 67; J. C. Poggendorff, “Biog. Literarisches,” etc., Vol. I. pp. 959, 960; “Royal Society Catalogue of Scientific Papers,” Vol. III. pp. 29–31.

Grotthus’ theory was extended by Rudolf Clausius, and the latter’s theory in turn gave way to that of Svante Arrhénius. Clausius maintained that the exchanges were going on continuously, although no current was flowing; while the assumption of Arrhénius was that in every electrolyte, a certain number of molecules break up into ions and that all electrolytes contain some of these free ions. This is the much controverted dissociation theory (Dr. Henry S. Carhart’s Presidential Address).

The “Encycl. Amer.,” New York, 1903, Vol. II says that the establishment of the theory of electrolytic dissociation, which is due to the noted Swedish chemist, Svante Arrhénius, supplies a reasonable explanation of many chemical phenomena otherwise insoluble, and correlates various facts between which no connection was previously discovered. Two important publications by Arrhénius are “Sur la conductibilité galvanique des electrolytes” (1884), and a treatise in German on electro-chemistry (1902). (See “Le Moniteur Scientifique,” Avril 1904, pp. 241–243.)

Rudolf Clausius, German scientist (1822–1888), “one of the most celebrated mathematical physicists of the nineteenth century,” communicated in 1850 to the Berlin Academy of Sciences the paper wherein he announced the second law of thermo-dynamics, that “heat cannot of itself pass from a colder to a hotter body.” The honour of establishing the science of thermo-dynamics upon a scientific basis he thus shares with Rankine and Thomson (“Encycl. Amer.,” Vol. V. n. p.; “New Inter. Encycl.,” New York, 1902, Vol. IV. p. 711. For biography, consult Riecke, “Rudolf Clausius,” Göttingen, 1889; “Meyer’s Konversations-Lexikon,” Leipzig, 1894, Vol. IV. p. 213).

=A.D. 1805.=--Alexander Tilloch’s Philosophical Magazine, Vol. XXI. p. 279, has a letter addressed by W. Peel to the editor, under date Cambridge, April 23, 1805, relative to the “Production of Muriate of Soda by the Galvanic Decomposition of Water.” This is followed by a communication dated Pisa, May 9, 1805, from Dr. Francis G. Pacchiani, Professor of Philosophy at the Pisa University (Rees’ Encyclopedia, “Galvanism,” p. 15), to Lawrence Pignotti, Historiographer to the King, entitled “Formation of Muriatic Acid by Galvanism,” as well as by two letters, one from W. Peel, dated Cambridge, June 4, 1805, on “The Production of Muriates by the Galvanic Decomposition of Water,” and the other from Dr. Wm. Henry, dated Manchester, July 23, 1805, relative to the above-named processes and to the latter’s own experiments in the same direction.

REFERENCES.--Phil. Mag., Vol. XXII. pp. 153, 179, 188; XXIII. p. 257; XXIV. p. 183; XXVII. p. 82; XXVIII. p. 306; Sir Humphry Davy’s allusion to above, as well as his earlier experiments communicated to Dr. Beddoes, Sir James Hall, Mr. Clayfield and others, in “Bakerian Lectures,” London, 1840, pp. 2, 3; Sylvester, at A.D. 1806, and Donovan, at A.D. 1812; Lardner’s “Lectures on Science and Art,” Vol. I. p. 350; Faraday’s “Experimental Researches,” No. 314; J. F. Macaire, _Ann. Ch. et Phys._, XVII. 1821; Marni “Sulla formazione ...”; G. B. Polcastro, “Giorn. Ital. Letter del Dal Rio,” X. p. 182, 1805; Cioni and Petrini, Phil. Mag., XXIV. 167, 1806; The Paris Galvani Society, Phil. Mag., XXIV. p. 172, and Ann. de Ch., Vol. LVI, 1806; A. B. Hortentz, Phil. Mag., Vol. XXIV. p. 91, 1806; Leop. de Buch, Phil. Mag., Vol. XXIV. p. 244, 1806; Veau Delaunay, Phil. Mag., XXVII. p. 260, 1807; G. Innocenti, Nuova Scelta d’ Opuscoli, II. p. 96, 1807; P. Alemanni, _Phil. Mag._, Vol. XXVII. p. 339, 1807; C. H. Pfaff, Phil. Mag., XXVII. p. 338, and XXIX. p. 19; Ann. de Chim., Vols. LX. p. 314; LXII. p. 23, 1807–8; Wm. Henry, Phil. Mag., Vols. XXII. p. 183; XL. p. 337, 1805–1812; F. G. Pacchiani, in _Nuova Scelta d’ Opuscoli_, I. p. 277; Brugnatelli, An. di Chimica, Vol. XXII. pp. 125, 134 and 144; Edin. Med. and Surg. Journal, of July 1, 1805; Phil. Mag., Vol. XXIV. p. 176, for his letter to Fabbroni. For Dr. Wm. Henry, consult “Bibl. Britan.,” Vol. XV, An. VIII. pp. 35, 293; Phil. Mag., Vols. VII for 1830, p. 228; XXII. p. 183; XXXII. p. 277, and XL. p. 337; Phil. Trans., Part II for 1808.

=A.D. 1806.=--On Oct. 16, Mr. Wm. Skrimshire, Jr., addresses from Wisbech a letter to Mr. Cuthbertson on the absorption of electric light by different bodies.

In this letter, which is given in full at pp. 281–283 of the fifteenth volume of Nicholson’s Journal, he says he was led to his experiments by the well-known fact that when the electric current is passed through a lump of sugar it makes the latter appear luminous. He tried many calcareous species, chalk, Kelton stone, the phosphate, nitrate, sulphates of lime, etc. etc., and he details some of the results obtained, the most interesting being that given by the sulphuret of lime, commonly called Canton’s phosphorus, which, he says, is, by the electric explosion, rendered the most luminous of all the substances tried.

=A.D. 1806.=--Heidmann (J. A.), physician at Vienna, publishes his “Theorie der Galvanischen Electricität ...” or “Theory of Galvanic Electricity deduced from Actual Experimentation” (London, 1807). This had been preceded by other important electrical reviews at Vienna during the years 1799, 1803 and 1804.

As stated by Guyton de Morveau, Heidmann has given us in the above the complete history of galvanic electricity--including the experiments and observations of Aldini, Arnim, Biot, Boeckman, Carminati, Cavallo, Creve, Davy, Fontana, Fowler, Gilbert, Haldane, Hallé, Helebrandt, Humboldt, Nicholson, Pepys, Pfaff, Reil, Reinhold, Ritter, Valli, Vassalli-Eandi, etc. etc.--together with the description of the construction and the relation of all parts of the galvanic pile, which is called by him a galvanic battery. Heidmann also gives an account of his many interesting experiments with frogs placed in different liquids as well as with the galvanic chain, and he reviews all the known phenomena presented by the voltaic pile.

REFERENCES.--“Annales de Chimie,” Vol. LXI. p. 70; Phil. Mag., Vol. XXVIII. p. 97.

=A.D. 1806.=--Dr. Joseph Baronio of Milan constructs a galvanic pile composed exclusively of vegetable substances. He makes his discs, two inches in diameter, of beet roots (bietola rossa) and of walnut wood (legno di noce), the latter having been freed from all of its resinous substance by treatment in a solution of vinegar and cream of tartar. Through this pile, he produced convulsions in a frog by excitation with a leaf of cochlearia (spoon wort or scurvy-grass).

REFERENCES.--“Annales de Chimie,” Vol. LVII. pp. 64–67; Vol. LXII. p. 212; Phil. Mag., Vol. XXIII. p. 283; “Nota di Brugnatelli sopra una pila di sostanze vegetabili,” Pavia, 1805 (“Am. di Chim. di Brugnatelli,” Vol. XXII. p. 301); Volta, in Giorn. Fis. Med., Vol. II. p. 122.

=A.D. 1806.=--Sylvester (Charles), the author of the articles on “Galvanism and Voltaism” in Rees’ “Encyclopædia,” announces that he obtains muriatic acid from pure water by passing through it the galvanic current. Mr. Wollaston, however, asserts this cannot be done unless the current traverses some vegetable or animal substance containing that acid.

His first paper on the subject appeared in Nicholson’s Journal, 1806, Vol. XIV. pp. 94–98; in Gehlen’s Journ. der Chemie, Vol. II for 1806, pp. 152–153, and in Gilbert’s Annalen der Physik, Vol. XXV. pp. 107–112, 454–457. The paper following is entitled “Repetition of the Experiment in which Acids and Alkalies are Produced in Pure Water by Galvanism (no animal or vegetable matter, nor oxidable metal being present).”

REFERENCES.--Nicholson’s Journal, Vol. XV. pp. 50–52; Vol. XXIII. pp. 258–260; Gehlen’s Journal, Vol. II, 1806, pp. 155–158. For his other papers, consult Nicholson’s Journal, Vol. IX. p. 179; Vol. X. pp. 166–167; Vol. XIX. pp. 156–157; Vol. XXVI. pp. 72–75; Gilbert’s Annalen, Vol. XXIII. pp. 441–447; “Roy. Soc. Catal. of Sc. Papers,” Vol. V. pp. 900–901; Sturgeon’s Scientific Researches, Bury, 1850, p. 153; Sir Humphry Davy’s lecture “On some chemical agencies of electricity,” read Nov. 20, 1806; Annales de Chimie, Vol. LX. p. 314; Vol. LXI. pp. 330–331; “Bibl. Britan.,” Vol. XXXIII, 1806, p. 324.

=A.D. 1806.=--Maréchaux (Peter Ludwig), correspondent of the French Galvani Society at Wesel, is the first to construct an effective dry pile containing paper discs. He makes known through M. Riffault (Annales de Chimie, Vol. LVII for January 1806, p. 61), that water is not essential to the production of galvanic effects, and his experiments are repeated for the Chemical Society by M. Veau Delaunay, as shown in Journal de Physique, Messidor, An. XIV.

This “Maréchausian Pile,” or colonne pendule, as it was originally denominated, consists of pairs of oven-dried cardboard, pasteboard, or blotting-paper, and of copper discs all pierced in such manner as to be suspended by three silken cords which hold them fast in position. Sturgeon remarks (“Researches,” pp. 199 and 239) that in this dry column the electric pulsations are, in consequence of the very great number of interrupting papers, less frequent than in either the processes of Volta or in that of Seebeck, notwithstanding which the instrument produces slow pulsatory currents.

REFERENCES.--W. Sturgeon’s “Annals of Electricity,” Vol. I. p. 256, note; Vol. VIII. pp. 379, 484; Phil. Mag., Vol. XXIV. p. 183; Poggendorff, Vol. II. p. 46; “Roy. Soc. Cat. of Sci. Papers,” Vol. IV. p. 236; Gilbert’s Annalen der Physik, Vols. X.-XXVII passim, also Vol. XV. p. 98 and Vol. XVI. p. 115 giving a description of the Maréchaux electro-micrometer (screw and silver leaf), likewise Vol. XXII, containing an account of the observations made by M. Paul Erman.

=A.D. 1807.=--Young (Thomas), M.D., a very celebrated English scientist, “eminent alike in almost every department of human learning,” who was the associate of Davy at the Royal Institution, and who became the successor of Volta as Foreign Associate of the French Academy of Sciences, publishes his very elaborate “Course of Lectures on Natural Philosophy and the Mechanical Arts,” upon which he was assiduously engaged for five years, and a new edition of which was issued (with additional references and notes) by the Rev. P. Kelland, M.A., F.R.S., during the year 1845.

The above-named work comprises the sixty lectures which Dr. Young delivered during his connection with the Royal Institution and includes also his optical and other memoirs, as well as a very extended classified catalogue of publications in every leading department of science. His biographer in the “English Encyclopædia” remarks that Young’s lectures embody a complete system of natural and mechanical philosophy, drawn from original sources, and are distinguished not only by extent of learning and accuracy of statement, but by the beauty and originality of the theoretical principles. One of these is the principle of interferences in the undulatory theory of light. “This discovery alone,” says Sir John Herschel, “would have sufficed to have placed its author in the highest rank of scientific immortality, were even his other almost innumerable claims to such a distinction disregarded.” The first reception, however, of Dr. Young’s investigations of light was very unfavourable. The novel theory of undulation especially was attacked in the Edinburgh Review, and Dr. Young wrote a pamphlet in reply, of which it is said but one copy was sold, but it is now generally received in place of the molecular or emanatory theory.

His review and treatment of the field of electrical and magnetic phenomena, as may be imagined from the foregoing, is very extensive, and as no justice could be done it by making therefrom such extracts as would suitably come within the scope of the present “Bibliographical History,” only an extract from the lecture treating of “Aqueous and Igneous Meteors” will here be given.

Speaking of the aurora borealis, he says “that it is doubtful if its light may not be of an electrical nature. The phenomenon is certainly connected with the general cause of magnetism. The primitive beams of light are supposed to be at an elevation of at least 50 or 100 miles above the earth, and everywhere in a direction parallel to that of the dipping needle; but perhaps, although the substance is magnetical, the illumination, which renders it visible, may still be derived from the passage of electricity, at too great a distance to be discovered by any other test.... It is certainly in some measure a magnetical phenomenon; and if iron were the only substance capable of exhibiting magnetic effects, it would follow that some ferruginous particles must exist in the upper regions of the atmosphere. The light usually attending this magnetical meteor may possibly be derived from electricity, which may be the immediate cause of a change in the distribution of the magnetic fluid contained in the ferruginous vapours that are imagined to float in the air.”

The assumption of ferruginous particles or vapours, remarks Prof. Robert Jameson, of the Edinburgh University, seems, however, purely gratuitous and imaginary; and as iron is not the only substance or matter capable of exhibiting magnetic effects, light itself being susceptible of polarization, the above hypothesis is, therefore, untenable even on the ground upon which it has been rested by its author. But it is, nevertheless, certain that the cause of this luminous meteor is intimately connected with magnetism and electricity; or, rather, as the magnetic is variously modified and effected by the electric power, with the phenomena of electro-magnetism.

REFERENCES.--Young’s Catalogue for “Aurora Borealis” and “Terrestrial Magnetism” (“Lectures,” London, 1807, Vol. II. pp. 440–443, 488–490), “Journal Roy. Inst.,” Vol. I; Dr. George Peacock’s “Life of Thomas Young”; also “Miscellaneous Works of T. Young,” London, 1855; “Memoirs of the Life of Thos. Young,” London, 1831; also Vol. XIII of John Leitch’s “Hieroglyphical Essays and Correspondence,” all of which contain every contribution made by the scientist to the Phil. Trans., as well as many other important articles communicated by him to other scientific publications of his time; “Eloge Historique de Dr. Thomas Young,” par M. Arago, in Mém. de l’Acad. Roy. des Sc., etc., Tome XIII. p. 57; Quarterly Review for April 1814; Tyndall, “Heat as a Mode of Motion,” 1873, pp. 267, 268; Annales de Chimie, Feb. 1815; Whewell, “History of the Inductive Sciences,” 1859, Vol. II. pp. 92, 96, 106, 111–118.

=A.D. 1808.=--Pasley (Charles William), F.R.S., D.C.L., K.C.B., who was at the time aide-de-camp to Sir John Moore, became Major-General in 1841 and Lieutenant-General in 1851, gives at pp. 205, 292, Vol. XXIX, and at p. 339, Vol. XXXV of Tilloch’s Philosophical Magazine, a description of the original and improved methods of constructing his “polygrammatic telegraph.”

The apparatus, as first devised by him between the years 1804 and 1807, consists of four posts, each bearing a pair of pivoted arms, which latter can be placed at different angles to indicate all desired numerals and letters. After he had seen the French semaphore during 1809 he improved his telegraph, employing but one post, upon which were three pairs of pivoted arms representing hundreds, tens and units.

In 1823 Pasley (then a Lieutenant-Colonel, Royal Engineers) issued a pamphlet entitled “Description of the Universal Telegraph for Day and Night Signals,” wherein he announces the abandonment of the polygrammatic principle. For day service he employs an upright post with two movable arms attached to the top on a pivot. Each arm is capable of assuming seven different positions, besides the quiescent position called the stop, in which the arms are turned down and concealed by the post. To prevent signals being seen in reverse, another arm, called an indicator, is added to one side of the post. For night signals he places a central lamp at the top of the post, as well as a lamp at the end of each arm, and suspends a fourth lamp, as an indicator, upon a light crane projecting horizontally beyond the range of both movable arms. Motion to the arms was communicated by means of an endless chain passing over two pulleys. Up to this time the semaphores employed by the Admiralty had been constructed without provision being made for the display of night signals.

Pasley was the first to apply the heating power of the galvanic battery to a useful practical purpose. While engaged on the River Thames he was written to by Mr. Palmer (Alfred Smee, “Electro-Metallurgy,” p. 297), who advised him to employ the galvanic battery instead of the long fuse then in common use, and as soon as he was made acquainted with the method of operating he at once adopted it and applied it effectively, during the year 1839, to the removal of the sunken hull of the “Royal George,” at Spithead.

REFERENCES.--Sturgeon’s “Scientific Researches,” Bury, 1850, p. 174; Knight’s “Mech. Dict.,” Vol. I. p. 784; also “Documents relatifs à l’emploi de l’Electricité,” etc., Paris, 1841, taken from the United Service Journal and the “Militaire Spectateur Hollandais.” Consult likewise, “Trans. of the Society ... Arts,” Vol. XXXIX, London, 1821, for Peter Barlow, XL. pp. 76–100, and for Lieut. Nicolas Harris Nicolas, XL. p. 104; also Vol. XLII, London, 1824, for Mr. A. Westcott, pp. 165–166. A patented telegraph by James Boaz is alluded to in Vol. XII. pp. 84–87 of the Phil. Magazine.

Following close upon Pasley’s original telegraphic contrivance were several other methods of conveying intelligence at a distance, introduced at this period, worthy of mention here.

The Chevalier A. N. Edelcrantz, Swedish savant, sent to the London Society of Arts a model of his apparatus, which is to be found minutely described in Vol. XXVI. pp. 20, 184–189, of the Transactions of that institution. A description of his earlier contrivances for the same purpose had already been published at Stockholm in the year 1796, and after being translated into French had been noticed in William Nicholson’s Journal of Natural Philosophy for 1803. The one he finally adopted in 1808 consisted of ten boards placed in three vertical ranks, the central one having four boards and the side ranks three boards each. By this arrangement 1024 signals could be clearly shown, and it was possible, by observing the order in which the boards were exhibited, to make as many as 4,037,912 changes. He subsequently advised attaching lamps to the boards for night service. His system of working the boards, though very complicated, could be controlled by only one person, while the English method required several men to hold the shutters during heavy weather. As it was, his method is said to have been in constant use for fully twelve years prior to 1808 on both sides of the Baltic, and to have likewise served to transmit signals between Sweden and England.

Mr. Henry Ward, who had observed the difficulty with which the telegraph was worked at Blandford, in Dorsetshire, contrived the apparatus described in Vol. XXVI. pp. 20, 207–209 of the London Journal of the Society of Arts. The grooved wheels which are fixed upon the axis of the shutters to receive the ropes by which they are turned have the grooved portion of the rim formed in two segments, which are so attached to the periphery of the wheels by steel springs that they fly off and remain a little distance off when there is no strain upon the ropes, although so soon as a rope is pulled its pressure forces the segments into close contact with the solid rim of the wheel. In the segments are two notches, which, when the shutters are in either of their required positions, engage with a fixed catch so soon as the strain on the ropes is relaxed, and thus hold the shutters steady without any aid from the attendant. The pulling of a rope by drawing the segments close to the wheel releases the catch, and consequently enables the attendant to return any shutter to its original position.

Lieutenant-Colonel John Macdonald, F.R.S., who was already favourably known by two Reports on the Diurnal Variation of the Magnetic Needle observed at Fort Marlborough, Sumatra, and at St. Helena (Philosophical Transactions for 1796, p. 340, and for 1798, p. 397, also “Eighth Encycl. Brit.,” Vol. XIV. p. 54), publishes (1808–1817) two treatises upon his “Terrestrial Telegraph,” accompanied by an extensive “Telegraphic Dictionary.” His contrivance consists of thirteen boards or shutters arranged, like those of Edelcrantz, into three vertical ranks representing hundreds, tens and units. Twelve of the boards are capable of producing 4095 distinct combinations, and the thirteenth or auxiliary board, which is mounted over the centre of the apparatus, doubles that number. A flag or vane is added to the hundred side to distinguish it in whatever direction it may be viewed, and a ball sliding upon the staff which supports it affords the means of again doubling the number, so that, on the whole, 16,380 distinct signals can be obtained. He subsequently adopted a modification of the contrivance introduced by Pasley in 1809, and also described a sort of a “Symbolic Telegraph,” in which symbols like those of Dr. Hooke, but representing numerals instead of alphabetical characters, were dropped into open spaces denoting hundreds, tens and units. He further suggested a useful flag telegraph for the navy and devised several schemes for night telegraphs both for land and sea, one of which latter consists of three sets of four lights each, with an additional or director light to each set, affording the same extensive powers as his large board or shutter telegraph (Phil. Mag., Vols. LVII. pp. 88–93, and LVIII. pp. 99–103).

Major Charles Le Hardy communicates in 1808 to the London Society of Arts, Vol. XXVI. pp. 20, 180–183, a novel contrivance consisting of a large framework with nine radiating bars, representing the numerals from 1 to 9, and four sets of other bars intersecting them so as to form four concentric polygons, which latter express units, tens, hundreds and thousands; thousands being shown by the innermost polygon. Attached to the centre of the apparatus are four slender arms, carrying four square boards, the lengths of these arms being such that the board of one may, during the revolution of the arm, traverse the polygon which represents thousands, that of another the polygon representing hundreds, etc. By the addition of two other boards at the upper corners, one of which denotes 10,000 and the other 20,000, or, when displayed together, 30,000, the total range of the telegraph is from 1 to 39,999 (Philosophical Magazine, Vol. XXXIII. p. 343).

In the twenty-seventh volume of the Transactions of the London Society of Arts will be found the telegraphic devices of Knight Spencer and of Lieutenant James Spratt (pp. 20, 163–169), while the thirty-third volume contains (at pp. 23, 118–121) a description of the contrivance of Alexander Law, intended for service on both sea and land. These, it may be said, are the only additional telegraphic methods worthy of note introduced up to the time when the English Admiralty adopted the system proposed by Sir Home Popham in 1816. The “anthropo-telegraph” of Knight Spencer, though laid before the Society of Arts in 1808, had been used as early as 1805. It consisted merely of two circular discs of wicker work, painted white with a black circle in the centre, to be held in different positions with respect to each other. The device of Lieutenant Spratt was more simple still, for it consisted only in holding a kerchief in various positions; yet, simple as it was, it served as a means of communication between vessels before the battle of Trafalgar, and it was also successfully used to converse between Spithead and the ramparts at Portsmouth, etc.

REFERENCES.--For Mr. Knight Spencer’s other papers, see the Philosophical Magazine, Vols. XXXVI. p. 321, and XL. p. 206, and, for different methods of telegraphing, see Mr. Macdonald’s “Treatise,” published in 1817, as well as, more particularly, Vols. XXVI, XXXIV, XXXV, XXXVI of the _Transactions of the Society of Arts_; likewise Rohde’s “Système complet de Signaux ...” published 1835.

=A.D. 1808.=--Callender--Calendar (Elisha), of Boston, Mass., obtains, on Oct. 3, 1808, for his lightning rod, an American patent, which latter is the first one in the line of electricity issued by the United States.

REFERENCES.--H. L. Ellsworth’s “Digest of Patents,” Washington, 1840, p. 234; Edmund Burke, “A List of Patents,” Washington, 1847, p. 185; “List of United States Patents,” Washington, 1872, p. 67.

=A.D. 1808.=--Bucholz (Christoph--Christian--Friedrich), distinguished German chemist, receives his diploma as a physician at Rinteln, prior to graduating at the Erfurt University, and publishes “Ueber die Chimischen ... metallen,” giving a description of the chain bearing his name. The latter was the result of experiments made by him to prove that the electricity in the pile results from the oxidation of one of the metals and also to establish a comparison between the quantity of electricity obtained and the amount of oxygen absorbed by the one metal.

REFERENCES.--“Biographie Universelle,” Bruxelles, 1843–1847, Vol. III. p. 227; A. F. Gehlen, Jour. für Chem. und Phys., Vol. V; L. Figuier, “Exp. et Hist.,” Paris, 1857, Vol. IV. p. 426; “La Grande Encyclopédie,” Vol. VIII. p. 315, and also the letter of J. B. Van Mons to Bucholz, Brussels, 1810.

=A.D. 1808.=--Amoretti (Carlo), Italian naturalist, who was allowed (1772) to withdraw from the order of St. Augustine that he might devote himself exclusively to scientific researches, gives, in his “Della rabdomanzia ossia elettrometria,” a complete history of the divining rod, and treats also therein of animal magnetism, etc. His investigations of the electric polarity of precious stones show, among other results, that the diamond, the garnet and the amethyst are - E, while the sapphire is + E.

REFERENCES.--For a further account of the Virgula Divina, or divining rod (baguette divinatoire), see the “Gentleman’s Magazine” for 1751, Vol. XXI; also the notes at foot of pp. 91–106 of Baron Karl Von Reichenbach’s “Physico-Physiologicæ Researches,” translated by Dr. John Ashburner, London, 1851. In the latter, reference is made to Pierre Le Lorrain de Vallemont’s “La Physique Occulte,” etc. (1693), to a work written by Count J. de Tristan, to the “Mémoire,” etc., of Tardy de Montravel (1781) and to Pierre Thouvenel’s “Mémoires,” etc., the last named bearing the Paris-London imprint of 1781–1784, and attempting to show relations existing between the rod and electricity and magnetism. Allusion is likewise made in the afore-named work to the translation by Dr. Hutton (1803) of Jean Etienne Montucla’s (1778) improvement of Jacques Ozanam’s “Récréations Mathématiques et Physiques,” originally built upon Leurechon’s “Récréations Mathématiques,” and first published in Paris during the year 1724. For Reichenbach, see “Le Cosmos,” Nos. 703–705 for July 16, 23 and 30, 1898; “Cat. Sc. Pap. Roy. Soc.,” Vol. I. pp. 139–140; Vol. VIII. pp. 720, 721. Besides the above, reference should be had to the lecture of Prof. Rossiter W. Raymond before the Philadelphia Electrical Exhibition of 1884, and to the article in Paris Cosmos of Jan. 3, 1891, which alludes to the works of P. Lebrun (1702), Albert Fortis (1802), Dr. Charpignon (1848), Abbé Chevalier (1853), and M. E. Chevreul “De la baguette ...” (1854). Consult also, Eusebe Salverte, “The Philosophy of Magic.,” Vol. II. chap. xi. speaking of Pryce’s “Mineralogia Cornubiensis” (1778); Theod. Kirchmaier, “De Virgula divinatrice,” 1678; F. Soave, (Opus. Scelti, III. p. 253), 1780; F. M. Stella (Opus. Scelti, XIII. p. 427), 1790; G. B. San Martino (Opus. Scelti, XVII. p. 243), 1794; L. Sementini, “Pensieri e Sperimenti ...” 1811; A. M. Vassalli-Eandi (Opus. Scelti, XIX. pp. 215, etc.); Kiesser, Archiv., Vol. IV. p. 62; at Vol. I. p. 265, of Blavatsky’s “Isis Unveiled”; “Biographie Générale,” Vol. II. pp. 290, 291; “Roy. Soc. Catal. of Sc. Papers,” Vol. I. p. 58.

=A.D. 1808.=--Lebouvier-Desmortiers (Urbain René Thomas), French writer, who had called attention to the danger attending the bodily application of the galvanic fluid, through the Journal de Physique of 1801 (p. 467), transmits another Mémoire to the same publication upon an improved electrical (briquet) tinder box.

The cylinder, which had previously been made of copper, he constructed of glass as illustrated by Delaunay at Plate IX. fig. 105, of his “Manuel,” etc., Paris, 1809. With the new contrivance he was enabled to exert considerable force upon the piston, and it was generally necessary to push the latter suddenly in order to so compress the air as to light the (amadou) spunk attached to the lower portion of the cylinder.

REFERENCES.--See his “Examen des principaux systèmes ...” Paris, 1813; J. C. Poggendorff, Biogr. Liter. Hand. ... Vol. I. p. 1399; Larousse, Dict. Univ., Vol. X. p. 290; Journal de Médecine, Vol. XXVI. pp. 298–303; _Catal. Sc. Pap. Roy. Soc._, Vol. III. p. 910; C. H. Wilkinson, “Elements of Galvanism,” London, 1804, Vol. I. p. 461; V. Delaunay, “Manuel de l’Electricité,” Paris, 1809, pp. 151–153; Detienne, “De l’électricité de pression” (Journal de Physique, 1777, Vol. IX).

=A.D. 1809.=--Krafft (Wolfgang Ludwig), Professor of Experimental Philosophy in the Imperial Academy of Sciences of St. Petersburg is the author of “Uber ein hypothet ...” wherein is given the result of his investigations of the phenomena of terrestrial magnetism.

Comparing Biot’s examination of the dip observations previously made by Humboldt, Krafft simplified the former’s conclusions, showing that if we measure the latitude from the magnetic equator, the tangent of the dip is double the tangent of such latitude, or, as he expresses it: “If we suppose a circle circumscribed about the earth, having the two extremities of the magnetic axis for its poles, and if we consider this circle as a magnetic equator, the tangent of the dip of the needle, in any magnetic latitude, will be equal to double the tangent of this latitude.”

Krafft gave a complete theory of the electrophorus in the first part of the 1778 “Acta Acad. Petrop.,” which latter also contains his experiments with Canton’s phosphorus and his observations on the aurora of February 6–17 of the same year. The results of many of his other investigations are to be found in Part XI of the work mentioned as well as in Vols. XV, XVII and XIX of the “Novi Commentarii Academiæ Petropolitanæ.”

=A.D. 1809.=--Pinkerton (John), gives in his “Voyages and Travels,” published at London (Vol. IV. pp. 1–76) a reprint of the rare volume entitled “Account of Paris at the close of the Seventeenth Century,” by Martin Lister, M.D., wherein are detailed several surprisingly interesting experiments made by Mr. Butterfield with his wonderful collection of loadstones. It is therein stated that one of these loadstones, when unshod, weighed less than a dram and would suspend a dram and a half, but when shod would attract 144 drams of iron, whilst another of the loadstones, weighing 65 grains, attracted 14 ounces, or 140 times its own weight; another would work through a wall eighteen inches in thickness, etc. etc.

=A.D. 1809.=--Children (John George), an English scientist to whom reference has already been made, more particularly under Cruikshanks, A.D. 1800, communicates to the Philosophical Transactions, “An account of some experiments performed with a view to ascertain the most advantageous method of constructing a voltaic apparatus for the purposes of chemical research.” This paper appears also in Vol. XXXIV of the Philosophical Magazine.

Four years later (1813) he publishes a description of his magnificent galvanic battery, the largest ever constructed on the plan suggested by Dr. Wollaston. This consisted of twenty pairs of copper and zinc plates, each six feet long and two feet eight inches wide, the united capacities of the cells being 945 gallons. With this battery he confirmed Davy’s observation that “intensity increases with the number (of plates) and the quantity of the electricity with the extent of surface.” It is reported that, when in full action, the battery rendered a platinum wire five feet six inches long and ¹¹⁄₁₀₀ of an inch in diameter red-hot throughout so as to be visible in full daylight; that eight feet six inches of platinum wire ⁴⁴⁄₁₀₀ of an inch in diameter were easily heated red; that a bar of platinum one-sixth of an inch square and two and a quarter inches long was heated red-hot and fused at the end; and that a round bar of the same metal, ²⁷⁶⁄₁₀₀₀ of an inch in diameter and two and a half inches long, was heated bright red throughout.

The result of many other investigations which he also made in 1813 and during 1815 showed that metallic wires (eight inches long and ¹⁄₃₀ of an inch diameter) became red-hot in the following order: platinum, iron, copper, gold, zinc, silver; and he deduced that their conducting power was in the inverse order, silver conducting best and platinum least. Tin and lead fused immediately at the point of contact, and the oxides of tungsten, uranium, cerium, titanium, iridium and molybdenum were also fused. An opening made with a saw across an iron wire having been filled with diamond powder, the diamond was liquefied and the contiguous iron became steel. (See the Pepys entry at A.D. 1802.)

REFERENCES.--For Children’s other experiments, consult “_Phil. Mag._,” Vol. XLII. p. 144; Vol. XLVI. pp. 409–415; _Phil. Trans._ for 1815, pp. 368–370, also Dr. Wm. Henry’s “Elem. of Exper. Chem.,” London, 1823, Vol. I. pp. 168–174; Dr. Thomas Thomson, “Outline of the Sciences,” London, 1830, pp. 524–526; Louis Figuier, “Expos. et Hist. ...” Paris, 1857, Vol. IV. pp. 389–390; Becquerel, Vol. I. p. 52; “Encycl. Metrop.,” Vol. IV. pp. 179, 222; Gmelin’s “Chemistry,” Vol. I. p. 424; “Cat. Sc. Papers Roy. Soc.,” Vol. I. p. 317; Vol. II. p. 26; “Bibl. Britan.,” Vol. XLIII, 1810, p. 67 and Vol. I of the N.S. for 1816, p. 109.

=A.D. 1809–1810.=--Oken (Lorenz)--originally Lorenz Ockenfuss--celebrated German naturalist, while occupying the post of Extraordinary Professor of Medicine at the University of Jena, publishes the great work “Lehrbuch der Naturphilosophie,” which was translated into English by Dr. A. Tulk and published in London, during 1847, by the Royal Society, under the title of “Elements of Physico-Philosophy.”

This work, says his biographer in the “English Cyclopædia” (Vol. IV. p. 557), takes the widest possible view of natural science: it is interesting as a document in the history of a great mental movement and contains the germs of those principles which are now regarded as the secure generalization of well-observed facts.

From the epitome of the work given in the “Encyclopædia Britannica,” the following is extracted: “Polarity is the first force which appears in the world.... Galvanism is the principle of life ... the vital force ... the galvanic process is one with the vital process.... There is no other vital force than the galvanic polarity.”

According to Dr. Richard Owen, Lorenz Oken contends that organism is galvanism residing in a thoroughly homogeneous mass. A galvanic pile, pounded into atoms, must become alive. In this manner, nature brings forth organic bodies. The basis of electricity is the air; of magnetism, metal; of chemism (the name he gives to the influence that produces chemical combination), salts. The basis of galvanism, in like manner, is the organic mass. Accordingly, whatever is organic is galvanic; whatever is alive is galvanic. Life, organism, galvanism, are one. Life is the vital process; the vital process is an organic or galvanic process. Galvanism is the basis of all the processes of the organic world.... God did not make man out of nothing, but took an elemental body then existing, an earth-clod or carbon, moulded it into form, thus making use of water, and breathed into it life, viz. air, whereby galvanism or the vital process arose.... Organization is produced by the co-operating process of light and heat. The ether imparts the substance, the heat the form, the light the life.... The life of an inorganic body is a threefold action of the three terrestrial elements, in which three processes galvanism consists. The nutrient process is magnetic, present and entire in every part of the body, and wheresoever it is withdrawn there is death.... These three processes constitute the galvanic process. Thus the galvanic circle is complete, and motion is the manipulation of galvanism. The process of motion is synonymous with the galvanic process--this is the vital process.

REFERENCES.--The extended biography of Lorenz Oken, embracing a list of his chief works and original essays at pp. 498–503, Vol. XVI of the Eighth “Encycl. Britan.”; Dr. William Whewell’s “History of the Inductive Sciences,” 1859, Vol. II. p. 477; “Hist. des Sciences,” par F. L. M. Maupied, Paris, 1847, Vol. II. pp. 466–514.

=A.D. 1809.=--Luc (Jean André de), celebrated natural philosopher of Swiss extraction (though from 1773 until his death in 1817, a resident of England, where he became reader to Queen Charlotte, the consort of George III), transmits to the Royal Society a long paper treating of the separation of the chemical from the electrical effects of the pile, with a description of the electric column and aerial electroscope.

In this communication, says Dr. Young, he advanced opinions so little in unison with the latest discoveries of the day, especially with those of the President of the Royal Society, that the Council probably thought it would be either encouraging error or leading to controversy to admit them into the Philosophical Transactions. He had, indeed, on other occasions shown somewhat too much scepticism in the rejection of new facts; and he had never been convinced even of Mr. Cavendish’s all-important discovery of the composition of water.

The paper was afterwards published in Nicholson’s Journal (Vol. XXVI), and the dry column described in it was constructed by various experimental philosophers. It exhibited a continual vibrating motion, made sensible by the sound of a little bell, which was struck by the pendulum at each alternation; and during many months the vibration was more or less rapid, according to circumstances affecting the column.

This dry column consists of discs of Dutch gilt paper, alternated with similar discs of laminated zinc, so arranged that the order of succession will be maintained throughout. When sufficiently dry these are piled upon each other, the gilt side of the paper being in contact with the zinc, and all are pressed together in a glass tube by a brass cap and screw connected at each end with a metallic wire. The column presented by De Luc to the Royal Society consisted of 300 discs of zinc and of 300 discs of gilt paper. It is said that, with a larger column, the vibration of a brass ball suspended between two bells was so continued as to maintain a perpetual ringing for over two years; that with an apparatus comprising 20,000 groups of silver, zinc and double discs of writing paper, sparks have been obtained, while a Leyden jar was charged in ten minutes with sufficient electricity to produce shocks and to fuse an inch of platinum wire of an inch in diameter; and that a similar pile, in the Clarendon Laboratory at Oxford, rang ten small bells continuously for over forty years.

In Vols. XXXV, XXXVI and XXXVII of the “Phil. Mag.,” and in Vols. XXVII and XXVIII of “Nicholson’s Journal,” André de Luc shows how the dry column can be used for determining the insulating qualities and conducting power of bodies, it having been also employed as are aerial electroscopes to indicate the electrical changes taking place in the atmosphere. The other volumes of the same publications named below contain additional papers upon electricity, galvanism, etc., while at p. 392, Vol. L of the Phil. Mag. will be found an account of De Luc’s life and principal works, the latter being likewise mentioned in Vol. XXV of the “Biographie Universelle.”

REFERENCES.--B. M. Forster, “Description ... elec. col. ... De Luc ...” London, 1810; Phil. Mag., Vol. XXXVII. p. 197; J. D. Maycock, Phil. Mag., Vol. XLVIII. pp. 165, 255; L. Configliachi, “Osservazioni sulle pile a secco”; M. Delezenne, “Expériences sur les piles sèches”; Bibl. Brit. Sci. et Arts, Vol. XLVII, 1811, pp. 3, 113, 213, 313; Vol. XLIX, 1812, pp. 88–92 (Necrology of J. A. De Luc), Vol. L, 1812, p. 351 (“Nicholson’s Journal,” No. 126), also the “Bibl. Britan.” for 1812, Vol. L. pp. 279–290 (Nicholson’s Journal, April 1812), for J. D. Maycock’s reply to De Luc’s objections concerning voltaic plates (“Phil. Mag.,” Vol. XLVIII. pp. 165, 255); Gmelin’s “Chemistry,” Vol. I. pp. 424–427; G. J. Singer’s “Elements of Electricity” and William Sturgeon’s Annals of Electricity, passim, as well as his “Researches,” Bury, 1850, pp. 147, 199, 261; De la Rive’s “Treatise on Electricity,” Vol. II. p. 852; Annales de Chimie et de Physique, Vol. II. pp. 79–82 for May 1816; Gilbert’s Annalen, Vol. XLIX; also Vols. VII, 1801, to Vol. LXXIV, 1821, for various articles upon the dry pile, etc.; G. Schübler, “Uber De Luc’s Elektr. saüle ...” 1813; Geo. Wilson’s “Life of Cavendish,” London, 1851, p. 66, etc.; “Nicholson’s Journal,” Vols. XXI, XXII, XXXII, XXXIII, XXXV; Phil. Mag., Vols. XLII, XLV, the last named containing, at pp. 359–363, Mr. G. J. Singer’s paper on “The Electric Column considered as ... first mover for Mechanical Purposes,” while at pp. 466, 467 is the communication of Mr. Francis Ronalds on De Luc’s electric column. The latter is also specially referred to in Vols. XLIII. pp. 241, 363; XLVI. p. 11; XLVII. pp. 47, 48; XLVIII. pp. 165, 255; LVII. pp. 446, 447; while at p. 55 of Vol. XLIX is a paper relative to a “combination of the electric column, the thermometer, barometer and hygrometer in one instrument, for electro-atmospherical researches.”

=A.D. 1809.=--Sömmering (Samuel Thomas von), German anatomist and physiologist, first employs voltaic, or contact, electricity for the transmission of telegraphic signals.

Both his original and perfected working instruments were constructed between July 9 and August 6, 1809 (Journal Franklin Institute, 1859, Vols. XXXVII and XXXVIII; Journal Society of Arts, Vol. VII. p. 235). The complete apparatus consists of thirty-five gold rods placed into glass tubes starting from a reservoir of acidulated water and connecting with thirty-five silk-covered wires, which are run into thirty-five apertures of copper (corresponding with twenty-five letters and ten figures) upon a wooden stand into each opening of which the wires of the voltaic pile can be inserted. When the latter are connected, the bubbles rising through the decomposition of the water are made to enter the lettered glass receivers through which the messages can be deciphered. On August 8, 1809, he was able to transmit intelligence a distance of 1000 feet, and twenty days later he presented his apparatus to the Bavarian Academy of Sciences (Fahie, “Hist. of Electric Telegraphy,” p. 228).

Sömmering’s telegraph was carried by Dominique Jean Larrey, chief surgeon of the French armies, to Paris, where it was delivered by him to the French Academy of Sciences, Dec. 5, 1809, and Dr. Hamel states that Biot, Carnot, Charles and Monge were appointed by that body to report upon the new invention (Journal of the Franklin Institute for 1859, Vol. XXXVIII. p. 398). In 1810 and 1811, Sömmering reduced the number of wires in his apparatus to twenty-seven. These brass or copper wires were first insulated with a covering of gum lac and then with silk thread, after which they were united into a thread-covered cable 1000 feet in length. The cable was in turn covered with heated gum lac or with a ribbon plunged in a solution of the same substance. The Russian Count Jeroslas Potocki took the new instrument to Vienna and submitted it, July 1, 1811, to the Emperor Francis I, while another model of the apparatus was sent to William Sömmering, then at Geneva, where it was shown to De la Rive, Auguste Pictet and other scientists. During March 1812 this instrument carried intelligence 10,000 feet, or ten times the distance previously reached.

REFERENCES.--Dr. Hamel, Cooke’s reprint, pp. 7, 8. See Sömmering’s own description of this, the first electro-chemical telegraph, in “Der Elektrische,” etc., published by his son William at Frankfort, 1863, or the translations at p. 751 of Noad’s “Manual,” London, 1859, and at pp. 230–234 of Fahie’s “Hist, of Elec. Tel.,” London, 1884; Dr. Hamel, in Jour. Soc. of Arts, for 1859, p. 453, or the reprint of W. F. Cooke in 1859, Vol. VII. pp. 595–599 and 605–610; Du Moncel, “Exposé,” etc., Vol. III; Comptes Rendus, Tome VII for 1838, p. 81; “De Bow’s Review,” Vol. XXV. p. 551; Highton’s “Elec. Tel.,” p. 39; Harris, “Galvanism,” p. 35; Sturgeon’s Ann. of Elec., Vol. III, March 1839, pp. 447–448; “Turnbull, Electric Magn. Tel.” “Denkschr. Münch. Akad. ...” for 1809 and 1810, alluding to his first experimental instrument made in 1807; Schweigger, Journal, II. pp. 217, 240 of Vol. XX for 1817; Poggendorff’s Annalen, Vol. CVII. pp. 644–647; “Smithsonian Report” for 1878, pp. 269–271; Journal of the Franklin Institute for 1851, Vol. XXI. pp. 330–332; Prime’s “Life of Prof. Morse,” 1875, pp. 263–275; “Bibl. Britan.,” Vol. XLIX, 1812, p. 19; “Traité de tél. sous-marine,” E. Wünschendorff, Paris, 1888.

=A.D. 1810.=--Prechtl (Johann Joseph), German mathematician and chemist, director of the School of Arts and Navigation in Trieste, also professor in the Vienna Polytechnic Institute, is the author of several very interesting articles on electricity, magnetism, etc., which appeared in Gilbert’s Ann. der Physik from Vol. XXXV for 1810, to Vol. LXVIII for 1821, as well as in Gehlen’s Jour. für Chemie, Physik und Mineralogie, Vols. V-VII. According to Figuier (“Expos, et Hist. ...” 1857, Vol. IV. p. 433) we owe to Prof. Prechtl a still more lucid explanation of the theory of electric distribution and equilibrium in the voltaic pile than was conveyed even by the learned Prof. Jäger (A.D. 1802).

Of the many separate treatises which he wrote up to 1836, and which are contained in the numerous publications cited below, the most important, by far, is doubtless that treating of the fundamental state of the magnetic phenomena of the electrical connecting wire and on the transverse electrical charge (“Uber d. transversal-magnetismus ...”) which is to be found in Schweigger’s Journal für die Chemie und Physik, Vol. XXXVI. pp. 399–410, and in Dr. Thomas Thomson’s Annals of Philosophy, N.S., Article I. vol. iv. pp. 1–6 for July 1822. Alluding to the last named, Mr. Sturgeon says (“Scientific Researches,” Bury, 1850, p. 29) that an attempt is made by M. Prechtl to explain the manner in which the connecting wire acts upon the needle, but that his diagrams and his mode of reasoning are too complex to be entered into the “Researches.”

REFERENCES.--Poggendorff’s “Biograph.-Liter. ...” Vol. II. pp. 519, 520; Larousse, “Dict. Univ.,” Vol. XIII. p. 45; “Catal. Sc. Papers Roy. Soc.,” Vol. V. pp. 3–5; Gehlen’s Journal, Vols. VII. pp. 141–282; VIII. pp. 297–318; Gilbert’s Annalen, Vols. XXXV, 1810, pp. 28–104; XLIV, 1813, pp. 108–111; LXVII, 1821, pp. 81–108, 221, 222, 259–276; LXVIII, 1821, pp. 104–106, 187–206; LXXVI, 1824, pp. 217–228; Brugnatelli’s “Giornale,” Vol. III, 1810, pp. 477–486; Kastner, “Archiv. Natur.,” II, 1824, pp. 151–167; Wien, “Jahrb. Pol. Inst.,” Vol. XIV, 1829, pp. 144–160, and Poggendorff’s Annalen der Physik und Chemie, Vol. XV, 1829, pp. 223–238.

=A.D. 1810.=--The compiler of this “Bibliographical History” will doubtless be pardoned for introducing here an additional mode of “communicating intelligence” promptly at great distances. Reference is made to the first germ of pneumatic telegraphy sown by the English engineer, George Medhurst, during the year 1810.

The London Telegraphic Journal, which gives an extract from the specification of Medhurst’s patent “for a new method of conveying letters and goods with great certainty and rapidity by air,” states that the process took practical form only in 1854, when Latimer Clark laid down a one-and-a-half-inch lead pipe between the Electric Telegraph Company’s central station, Lothbury, and the London Stock Exchange. The system was extended in 1858 to Mincing Lane, and, two years later, Varley introduced the use of compressed air, so that messages were drawn one way by a vacuum, and propelled in the opposite direction by a prenum, instead of employing a vacuum both ways, as Latimer Clark had previously done. During the year 1865 the system, then considerably modified, was introduced into Paris, and it was also made use of, at about the same time, by the Messrs. Siemens, who employed it between the Bourse and the telegraph station in the city of Berlin.

=A.D. 1810.=--Jacopi (Joseph), Italian physician, anatomist and physiologist (1774–1813), pupil of the famous Scarpa, makes known through his “Elementi di Fisiologia e Notomia comparata” (“Eléments de Physiologie et d’Anatomie comparée”), the results of his very extended investigations of the electrical organs of the torpedo.

To him is due the first clear description of the electrical lobes situated in the torpedo’s brain and of its relation to the eighth pair of nerves distributed throughout the hexagonal columns, which latter received also from him a very extended notice in the above-named work. The fifth ramification of nerves was first observed by Carus, and the most valuable investigation relative to the fourth and last important group of nerves directly connected with the electrical organs was made by the celebrated Italian professor, Carlo Matteucci.

REFERENCES.--Larousse, “Dict. Univ.,” Vol. IX. p. 867; C. Matteucci, “Traité des Phénomènes Electro-Phys.,” Paris, 1844, pp. 283–318; Geoffroy St. Hilaire at A.D. 1803.

Another author, Delle Chiaje, likewise gave a description of the rhomboidal sinus-shaped protuberance which he calls lobo pagliarino (straw-coloured lobe), and which he considers as formed of one mass but does not admit its important connection with the electrical organs.

=A.D. 1811.=--Poisson (Siméon Denis), a very able French scientist, communicates to the “Institut des Mathématiques et Physiques” and publishes at Paris under the caption “Traité de Mécanique,” his analytical observations of the electric phenomena which, it has been truly said, actually establish a new branch of, and is the best elementary work extant upon, mathematical physics. One of his biographers remarks that Poisson’s object was “to leave no branch of physics unexplored by aid of the new and powerful methods of investigation which a school, yet more modern than that of Lagrange and Laplace, had added to the pure mathematics.”

As shown, notably by Sir David Brewster in his able article on “Electricity” in the eighth “Encycl. Brit.” (Vol. VIII. p. 531), and by Noad, in his “Manual” (London, 1859, pp. 15, 16):

“Poisson adopted as the basis of his investigations the theory of two fluids, proposed by Symmer and Dufay, with such modifications and additions as were suggested by the researches of Coulomb. He deduced theorems for determining the distribution of the electric fluid on the surfaces of two conducting spheres, when they are placed in contact or at any given distance, the truth of which had been established experimentally by Coulomb before the theorems themselves had been investigated. On bodies of elongated forms, or those which have edges, corners or points, it is shown as a consequence of the theory of two fluids that the electric fluid accumulates in greater depths about the edges, corners or points than in other places. Its expansive force, being therefore greater at such parts than elsewhere, exceeds the atmospheric pressure and escapes, while at other points of the surface it is retained.”

In the latter connection Mary Somerville remarks:

“There can hardly be a doubt but that all the phenomena of magnetism, like those of electricity, may be explained on the hypothesis of one ethereal fluid, which is condensed or redundant in the positive pole, and deficient in the negative; a theory that accords best with the simplicity and general nature of the laws of creation; nevertheless, Poisson has adopted the hypothesis of two extremely rare fluids, pervading all the particles of iron, and incapable of leaving them. Whether the particles of these fluids are coincident with the molecules of the iron, or that they only fill the interstices between them, is unknown and immaterial. But it is certain that the sum of all the magnetic molecules, added to the sum of all the spaces between them, whether occupied by matter or not, must be equal to the whole volume of the magnetic body.... M. Poisson has proved that the result of the action of all the magnetic elements of a magnetized body is a force equivalent to the action of a very thin stratum covering the whole surface of a body, and consisting of the two fluids--the austral and the boreal, occupying different parts of it; in other words, the attractions and repulsions externally exerted by a magnet are exactly the same as if they proceeded from a very thin stratum of each fluid occupying the surface only, both fluids being in equal quantities, and so distributed that their total action upon all the points in the interior of the body is equal to nothing. Since the resulting force is the difference of the two polarities, its intensity must be greatly inferior to that of either” (J. C. Wilcke at A.D. 1757, “Conn. of the Phys. Sci.,” 1846, s. 30 pp. 308, 309).

The “Mémoires de l’Institut” for 1811 contain Poisson’s very able papers showing the manner in which electricity is distributed on the surfaces of bodies of various figures and the thickness of the stratum of electricity existing throughout these bodies. Mrs. Somerville further observes of work already cited (s. 28):

“Although the distribution of the electric fluid has employed the eminent analytical talents of M. Poisson and M. Ivory, and though many of their computed phenomena have been confirmed by observation, yet recent experiments show that the subject is still involved in much difficulty. Electricity is entirely confined to the surface of bodies; or, if it does penetrate their substance, the depth is inappreciable; so that the quantity bodies are capable of receiving does not follow the proportion of their bulk, but depends principally upon the form and extent of surface over which it is spread; thus the exterior may be positively or negatively electric, while the interior is in a state of perfect neutrality.” (Consult J. Farrar, “Elem. of Elect. Magn. and Electro-Magn.,” 1826, pp. 50–56.)

In his treatment of the theories of magnetism, Brewster alludes again to the masterly investigations of Poisson, who, says he, appears to have been “the first to conceive the idea of absolute magnetic measurement.” In a short but luminous article at the end of the “Connaissance des Temps” for 1828, he describes the method for obtaining the value of H[ symbol] in absolute measure. His first and second “Mémoire sur la Théorie du Magnétisme” appeared during 1824–1825, at pp. 247, 488, Vol. V of the Transactions of the Paris Royal Academy, and were closely followed (Vol. VI. p. 441) by his Memoir on the theory of Magnetism in motion. Translations of these will be found at pp. 336–358, 373, Vol. I and pp. 328–330, Vol. V of the Edin. Jour. of Sci. and at pp. 334, 335 of John Farrar’s “Elem. of Elect. Magn. and Electro-Mag.,” all published during the year 1826.

Poisson’s theoretical prediction of magne-crystallic action is thus alluded to by Dr. John Tyndall in his “Researches on Diamagnetism,” etc., London, 1870, pp. 13 and 66, 67:

“In March 1851, Professor William Thomson (Lord Kelvin) drew attention to an exceedingly remarkable instance of theoretic foresight on the part of Poisson, with reference to the possibility of magne-crystallic action.

“Poisson,” says Sir William, “in his mathematical theory of magnetic induction founded on the hypothesis of magnetic fluids (moving within the infinitely small magnetic elements), of which he assumes magnetizable matter to be constituted, does not overlook the possibility of those magnetic elements being non-spherical and symmetrically arranged in crystalline matter, and he remarks that a finite spherical portion of such a substance would, when in the neighbourhood of a magnet, act differently according to the different positions into which it might be turned with its centre tube fixed. But (such a circumstance not having yet been observed), he excludes the consideration of the structure which would lead to it from his researches, and confines himself in his theory of magnetic induction to the case of matter consisting either of spherical magnetic elements or of non-symmetrically disposed elements of any forms. Now, however, when a recent discovery of Plucker’s has established the very circumstance, the observation of which was wanting to induce Poisson to enter upon a full treatment of the subject, the importance of working out a magnetical theory of magnetic induction is obvious.

“Sir William Thomson then proceeds to make the necessary ‘extension of Poisson’s Mathematical Theory of Magnetic Induction,’ and he publishes a striking quotation from the ‘Mémoires de l’Institut,’ 1821–1822, Paris, 1826.”

REFERENCES.--Biography in “English Encycl.,” Vol. IV. p. 899; Phil. Mag. for 1851; Roy. Soc. Catal. of Sci. Papers, Vol. IV. pp. 964–969; G. M. Racagni, “Sopra una Memoria ...” 1839; Johnson’s “Encycl.,” 1878, Vol. III. p. 227; eighth “Britannica,” Vol. XV. p. 98; ninth “Britannica,” Vol. XV. pp. 241, 249; Ann. de Chimie for Feb. 1824; “Le Globe,” No. 87; Harris, “Magnetism,” p. 131; Whewell, “Hist. of the Inductive Sciences,” 1859, Vol. II. pp. 43, 208, 209, 222, 223; Sir William Thomson’s works, 1872; Thomas Thomson, “An Outline,” etc., 1830, p. 351; Mém. de l’Acad. des Sci. for 1824–1826, 1838; Soc. Philom. for 1803, 1824–1826; Humboldt’s “Cosmos,” London, 1849, Vol. I. pp. 104, 105, 130, 165–169; N. Bowditch, “Of a mistake which exists in the calculation of M. Poisson relative to the distribution of the electric matter upon the surfaces of two globes, in Vol. XII of the “Mém. ... Sc. Math. ... de France”; Mem. Amer. Acad., O.S., Vol. IV. part i. p. 307; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 228. Mention is made of Poisson’s principal writings, in Vol. XI. pp. 179–191 of M. Max Marie’s “Hist. des Sciences Mathém.,” Paris, 1888, but the complete list will be found in Vol. II of the works of Arago.

=A.D. 1811.=--Schweigger (Johann Salomo Christoph), a chemist of Halle (1779–1857), inserts at p. 240, Vol. II of his Journal für die Chemie und Physik, the memoir of Sömmering, relative to his electro-chemical telegraph, as well as an appendix thereto, wherein he points out the difficulties likely to attend the employment of so many different wires. He suggests the use of but two wires, and of two piles of unequal power. With these, all desired characters could be transmitted, through a preconcerted code regarding the meaning of such letters and figures as would be represented by the weaker or the stronger pile, in conjunction with the duration of the gas evolutions or the space of time separating them. He also suggested, for an alarum, the use of a pistol, by connecting a battery to the pile, in lieu of liberating an alarm by means of accumulated gas as Sömmering had done.

Two months after Oersted’s great discovery, which was announced in July 1820, Schweigger read at Halle (September 16, 1820) and communicated to the German Literary Gazette (No. 296 for November 1820), a paper relative to an important improvement made in his galvano magnetic indicator. The latter, which had been described at pp. 206–208 of Gehlen’s (1808) Journal für Chemie, was merely an electroscope, employed to indicate the attraction and repulsion of ordinary frictional electricity in lieu of a Coulomb balance, the improved apparatus being the result of his discovery that, by coiling an insulated wire several times around a magnetic needle, the deflecting power of the voltaic current increases with the number of turns (Kuhn, “Ang. Elek.-Lehre,” p. 514).

Alluding to Schweigger’s multiplier, the Abbé Moigno says:

“A conducting wire twisted upon itself and forming one hundred turns will, when traversed by the same current, produce an effect one hundred times greater than a wire with a single turn: provided always that the electric fluid pass through circumvolutions of the wire without passing laterally from one contour to another” (Cornhill Magazine, Vol. II for 1860, pp. 61, 64).

It was, however, shown by Dr. Seebeck that the power of multiplication does not increase with the number of windings in the uniting wire, for the resistance to transmission naturally increases with the length of the wire, thus diminishing its conducting power.

To his new instrument Schweigger gave the name of electro-magnetic multiplier (multiplicator) or galvanometer multiplier, and it has become the most important for indicating and measuring the strength of the galvanic current.

Prof. W. B. Rogers says that Schweigger’s apparatus as improved by Nobili (Ital. Soc. Mem., Vol. XX. p. 173) became indispensable in the measurement of current electricity, and that through the later improvements given it by Sir William Thomson (also by Du Bois Reymond), it has been made one of the most perfect and delicate of all known means of measuring force. Schweigger’s multipliers with improvements made thereon by Oersted and Nobili are illustrated at p. 642, Vol. XXI of the eighth “Ency. Britannica,” where reference is made to drawings on a large scale shown at Plate 522, article “Thermo-Electricity,” of the “Edinburgh Encyclopædia.”

According to a footnote, p. 273 of “Report Smithsonian Inst.” for 1878, Schweigger’s multiplier is alluded to in the “Additions to Oersted’s Electroma-gnetic Experiments,” a memoir read at the Naturforschende Gesellschaft at Halle, September 16 and November 4, 1820. An abstract of this paper was published in the Allgemeine Literatur-Zeitung of Halle (4to), November 1820, No. 296, Vol. III. col. 621–624, whilst the full memoir appeared in the Journal für Chemie und Physik, 1821, Vol. XXXI. pp. 1–17; and “Additional Remarks ...” by Dr. Schweigger, in the same volume, pp. 35–41. It is further stated in the afore-mentioned note that:

“A galvanometer of somewhat different form, having a vertical helix and employing an unmagnetized needle, was very shortly afterward independently devised by Johann Christian Poggendorff, of Berlin; and as he preceded Schweigger in publishing an account of it, he is sometimes regarded as the original inventor. Schweigger designated his device an ‘Electro-magnetic Multiplicator’; Poggendorff designated his arrangement a ‘Galvano-magnetic Condensator.’ Prof. Oersted remarks: ‘Immediately after the discovery of electro-magnetism, M. Schweigger, professor at Halle, invented an apparatus admirably adapted for exhibiting by means of the magnetic needle the feeblest electric currents.... M. Poggendorff, a distinguished young savant, of Berlin, constructed an electro-magnetic multiplier very shortly after M. Schweigger, with which he made some striking experiments. M. Poggendorff’s work having been cited in a book on electro-magnetism by the celebrated M. Erman (published immediately after the discovery of these phenomena), became known to several philosophers before that of M. Schweigger’ (Annales de Chimie et de Physique, 1823, Vol. XXII. pp. 358–360).

“The researches of Schweigger and Bart leave us little or no doubt that the ancients were well acquainted with the mutual attraction of iron and the lodestone, as well as with the positive and negative properties of electricity, by whatever name they may have called it. The reciprocal magnetic relations to the planetary orbs, which are all magnets, was with them an accepted fact, and aerolites were not only called by them magnetic stones, but used in the Mysteries for purposes to which we now apply the magnet.”

REFERENCES.--“Isis Unveiled,” Vol. I. pp. 281, 282. See also Annales de Chimie et de Physique, 1816, Vol. II. pp. 84, 86; Thos. Thomson, “An Outline of the Sciences ...” London, 1830, Chap. XV. p. 564; “Encycl. Brit.,” seventh edition, “Voltaic Electricity,” p. 687; Polytechnisches Centralblatt; _Sc. Am. Supp._, No. 404; Sturgeon’s “Scientific Researches,” Bury, 1850, p. 19; L. F. Kaemtz, Phil. Mag., Vol. LXII. p. 441; Poggendorff, Vol. II. pp. 873–875; Du Moncel, “Exposé ...” Vol. III; Whewell’s “Hist. of Ind. Sci.,” Vol. II. p. 251; “Abhandl. d. Naturf. Gesellsch. zu Halle” for 1853–1856; Schweigger’s Journal für Chemie und Physik, Vol. II. part iv. pp. 424–434; Vol. X for 1814 and Vol. XXXVIII for 1823; “Cat. Sc. Papers Roy. Soc.,” Vol. V. pp. 589–592; “Bibl. Britan.,” Vol. XVI, N.S., 1821, p. 197; Larousse, Vol. XIV. pp. 386–387. _Edinburgh Philosophical Journal_, July 1821, Vol. V. p. 113. For Seebeck, see Phil. Mag., Vol. LXI, 1823, p. 146. For Poggendorff, see “Cat. Sc. Pap. Roy. Soc.,” Vol. IV. pp. 952–956; Vol. VIII. pp. 638–640; “Bibl. Britan.,” Vol. XVIII, N.S., 1821, p. 195; Pogg., “Annalen,” Vol. CLX (biography).

In the editorship of Schweigger’s Journal, which followed Gehlen’s Journal, Mr. J. S. C. Schweigger was assisted, from 1828, by Franz W. Schweigger-Seidel, who was the author of “Lit. d. Math. Natur.,” published in 1828. (For the joint magnetic work of J. S. C. Schweigger and Wilhelm Pfaff, see Jour. f. Ch. u. Ph., Band X. heft i. for 1814.)

=A.D. 1811.=--Monsieur Dessaignes is first to establish a relation between electricity and phosphorescence, as is shown in the extract published in London from the Memoir which he had presented two years before to the French Institute. The general view he takes is that phosphorescence is produced by a particular fluid, which is set in motion by light, by heat, by electricity, as well as by friction, and that it is dissipated by overheating or by too long exposure to light.

It is asserted by Fahie (“Hist. of El. Tel.,” pp. xiv, 297) that it was Dessaignes and not Seebeck who first discovered thermo-electricity. “Dessaignes,” he says, “showed us how difference of temperature or heat could produce electricity.” This was in 1815, or six years before Seebeck, who is always credited with the observation (Bostock’s “History of Galvanism,” London, 1818, p. 101). Many observations bearing on thermo-electricity had been made even long before Dessaignes.... In 1759 Æpinus called attention to the same phenomena, and pointed out that electricity of opposite kinds was developed at opposite ends of the crystal (tourmaline). In 1760 Canton observed the same properties in the topaz; and between 1789 and 1791 Haüy showed the thermo-electric properties of various other substances, as mesotype, prehnite, Iceland spar, and boracite.

REFERENCES.--Priestley’s “History of Electricity,” 1767, pp. 314–326. For Dessaignes’ other observations, see J. Farrar, “Elem. of Elec., Mag. and Electro-Mag.,” 1826, p. 125, and Phil. Mag., Vol. XLIV. p. 313. See also Phil. Mag., Vol. XXXVIII. p. 3; Journal des Mines, Vol. XXVII. p. 213; Poggendorff, Vol. I. p. 563; “Cat. Sci. Pap. Roy. Soc.,” Vol. II. pp. 272, 273; Chap. III. s. 3 of the “Electricity” article of the “Ency. Britannica.”

=A.D. 1811.=--The idea of placing a lightning conductor through the body of a ship is first suggested by Mr. Benjamin Cook, of Birmingham, and is carried out by Mr. William Snow Harris, of Plymouth. Mr. William Sturgeon, who mentions the fact (“Lectures of Electricity,” London, 1842, p. 208), adds that Mr. Harris “has formed the conductors into strips of copper, which are inserted in grooves in the after side of the masts from top to bottom and through the keelson to the sea. In one of the smaller men-of-war Mr. Harris carried his mizzen conductor through the powder magazine!!! The evils attending these conductors arise principally from lateral explosions and electro-magnetic influence.”

REFERENCES.--For Wm. Sturgeon, consult Phil. Mag., Vol. XI, 1832, pp. 195, 270, 324; “Cat. Sc. Papers Roy. Soc.,” Vol. V. pp. 876–878, Vol. VI. p. 758 and Vol. VIII. p. 1042.

=A.D. 1811–1812.=--Schübler (Gustav), Professor, of Tübingen, is the first to present a connected series of observations upon the electricity of the air, which were made at Stuttgart, during all kinds of weather and at regular daily intervals, between May 1811 and June 1812. Other observations previously carried on by Schübler, during 1805 and subsequent years, at Ellvanguen and Stuttgart are detailed at pp. 579, 580, Vol. VIII--and are also alluded to in article “Meteorology”--of the eighth “Britannica.”

While De Lor was the first to observe, in 1752, the existence of electricity in the atmosphere, even when no lightning is visible, Schübler made the earliest known report upon the daily periodicity of the intensity of the electricity. The annual periodicity had been previously demonstrated by G. B. Beccaria, who published at Turin two able treatises on the subject during 1769 and 1775.

The origin of atmospheric electricity was, by Lavoisier, Laplace and Sir H. Davy, attributed in great part to the constant combustion taking place upon the earth’s surface. Volta and Saussure believed it to arise from the process of evaporation, while Pouillet pointed out the influence of the processes of vegetation; Reich, however, showed that as neither developed electricity they could not produce it in the atmosphere. Peltier advanced the theory that mere evaporation without chemical action is not enough, and the experiments of Faraday and Armstrong showed that evaporation without friction is likewise insufficient. These theories are treated of in “Gaea-Natur und Leben,” Köln and Leipzig, 1873, p. 322, and in Lardner’s “Popular Lectures,” 1859, Vol. II. pp. 149–160. The last named gives tables of many observations, and reports, among other matters, that the series of observations on the diurnal changes of atmospheric electricity which Schübler made, in 1811–1812, were repeated and confirmed at Paris in 1830 by M. Arago. During the month of March 1811 Schübler found that the mean time of the morning maximum was eight hours thirty minutes, and M. Arago ascertained the mean time for the same month to be eight hours forty-eight minutes.

REFERENCES.--Edin. Jour. of Sci., new series, Vol. III; Biblio. Univers., Vol. XLII; Annales de Ch. et de Ph. for 1816, Vol. II. p. 85; “Jahrbuch der Ch. und Ph.,” 1829; Gilbert’s Annalen, Vols. XXXIX, XLIX, LI; Schweigger’s Journal, Vols. II. p. 377; III. p. 133; VIII. pp. 21, 22, 25, 26, 28, 29; IX. pp. 348, 350, 351; XV. p. 130; XIX. pp. 1 and 11; XXV. p. 249; XXXI. p. 39; Jour. de Phys., Vol. LXXV. p. 177; Vol. LXXXIII. p. 184; “Lehrbuch der Meteor,” L. F. Kaemtz, Halle, 1832, Vol. I. p. 337; Vol. II. pp. 411, 414; “Annual of Sc. Disc.” for 1862, pp. 99–103; L. Palmieri in Lum. Elec., Paris, Oct. 31, 1891, pp. 209–212; “Sci. Pap. Roy. Soc.,” Vol. V. pp. 559–562; Vol. VI. p. 755; “Bibl. Britan.,” Vol. II, N.S. for 1816 pp. 93–113 (atmosph. electricity); Poggendorff, Vol. II. p. 853; Report on Atmospheric Electricity by F. J. F. Duprez, 1858, Part III. chap. ii. pp. 363–368; Foggo, p. 124, Vol. IV of Edin. Jour. Sci.; J. J. Hemmer’s observations at Mannheim from 1783 to 1787, Lehrbuch, etc., Vol. II. p. 418, and the recorded investigations of De Luc, Girtannier, Mayer, Monge, Pouillet, Becquerel, De Tressan, Arago, De Saussure, Delezenne, Helwig and Kaemtz.

=A.D. 1811.=--In the first volume of his “Cosmos” (London, 1849, Vol. I. pp. 240–241) Humboldt speaks of islands of eruption, or marine volcanoes, which can properly be classed among electrical phenomena, and alludes to the one observed on the 13th of June 1811 by Captain Tillard (Tilland), and to which he gave the name “Sabrina.”

This volcano, which had previously appeared June 11, 1638 and December 31, 1719, off the island of St. Michael, in the Azores, is thus described in the Philosophical Transactions:

“Imagine,” says Captain Tillard, “an immense body of smoke rising from the sea, the surface of which was marked by the silver rippling of the waves occasioned by the slight and steady breezes incidental to those climates in summer. In a quiescent state, it had the appearance of a circular cloud, revolving on the water like a horizontal wheel, in various and irregular involutions, expanding itself gradually on the lee side, when suddenly a column of the blackest cinders, ashes, and stones, would shoot up in the form of a spire, rapidly succeeded by others, each acquiring greater velocity and breaking into various branches resembling a group of pines; these again forming themselves into festoons of white feathery smoke. During these bursts, the most vivid flashes of lightning continually issued from the densest portion of the volcano, and the columns rolled off in large masses of fleecy clouds, gradually expanding themselves before the wind, in a direction nearly horizontal, and drawing up a quantity of water spouts, which formed a striking addition to the scene. In less than an hour, a peak was visible, and, in three hours from the time of our arrival, the volcano then being four hours old, a crater was formed twenty feet high, and from four to five hundred feet in diameter. The eruptions were attended by a noise like the firing of cannon and musketry mixed; as also with shocks of earthquakes sufficient to throw down a large part of the cliff on which we stood.” (See description of the sudden appearance of the Island of St. Michael, etc., in Lectures by Dr. Webster, Professor of Chemistry and Mineralogy at Harvard College, Boston, 1822.)

=A.D. 1811–1818.=--Ure (Andrew), M.D., F.R.S., the first astronomer appointed to the Glasgow Observatory and the author of a Dictionary of Chemistry (the undisputed standard until the appearance of a similar work by Henry Watts), makes known the result of his electrical experiments in the same line as those made by Aldini (A.D. 1793) upon the body of a recently executed criminal. Noad, who gives a greatly detailed account of the investigations, at pp. 338–341 of his “Manual,” remarks that they “serve to convey a tolerably accurate idea of the wonderful physiological effects of the electrical agent, and will be impressive from their conveying the most terrific expressions of human passion and human agony.”

Dr. Ure is the inventor of an improved eudiometer, for detonating or exploding gases by means of an electric shock or spark, which is fully described and illustrated in the “Electricity” article of the “Britannica.”

REFERENCES.--De la Rive, “Treatise on Electricity,” Vol. II. pp. 489–490, also “Encycl. Metropol.,” Vol. IV (Galv.), p. 197. Another report of Ure’s experiments appears at pp. 634, 635 of the “Encycl. Brit.,” article on “Voltaic Electricity,” also in No. 12 of the Journal Sci. and Arts, and at p. 56, Vol. LIII of the Philosophical Magazine.

=A.D. 1812.=--Through the New York Columbian, of July 1812, Mr. Christopher Colles informs the public that the operation of his new telegraphs “will be shown from the top of the Custom House on Tuesdays, Thursdays and Saturdays from four to six o’clock in the afternoon.”

In an explanatory pamphlet, he states that “eighty-four letters can be exhibited by this machine in five minutes, to the distance of one telegraphic station averaged at ten miles, and by the same proportion a distance of 2600 miles in fifteen minutes, twenty-eight seconds.”

James D. Reid, who mentions this fact at p. 5 of his “Telegraph in America,” says that the above was nothing but the already well-known European semaphore or visual signal, and that Colles worked his “machine” between New York and Sandy Hook for several years.

=A.D. 1812.=--On April 1 and 15, May 13 and June 17, Mr. M. Donovan, secretary of the Kirwanian Society of Dublin, reads before the latter body a long communication “On the Inadequacy of the Hypothesis at Present Received to Account for (explain) the Phenomena of Electricity,” which was afterward ably criticized by J. A. de Luc, as will be seen by reference to the Philosophical Magazine, Vols. XLV. pp. 97, 200, 329–332, and XLVI. pp. 13, 14. In his treatment of Eeles’ hypothesis (see A.D. 1755) Donovan gives some attention to the designed suppression by Priestley of Eeles’ valuable papers from the Philosophical Transactions.

The above communication was followed by still more valuable and much longer ones, read by Mr. Donovan before the same society, February 22, March 8, and March 22, 1815, entitled “On the Origin, Progress and Present State of Galvanism ... and Inadequacy of the Hypotheses to Explain Its Phenomena ...” a modified form of which obtained for its author the prize of the Irish Royal Society.

The sketch of the history of galvanism is divided into three periods. The first treats of the discoveries attaching to muscular contraction, and alludes to the observations of Sulzer, Galvani, Fabbroni, Humboldt, Pfaff, Fontana, Valli, Monro, Vassalli-Eandi, Fowler, Smuck, Marsigli, Grapengieser, Giulio, Rossi, Aldini and Wells. The second period reviews the gradual development of the physical and chemical power of combined galvanic arrangements, beginning with Nicholson and Carlisle, and refers to the many conclusions reached by Cruikshanks, Henry, Haldane, Ritter, Robertson, Brugnatelli, Fourcroy, Vauquelin, Thénard, Lehot, Trommsdorff, Simon, Helwige (Major Helvig), Twast, Bourguet, Erman, Grapengieser, Wollaston, Davy, Pfaff, Van Marum, Biot, Cuvier, Desormes, Bostock, Cuthbertson, Aldini, Lagrave, Jordan, Ritter and Wilkinson. The third period commences with the well-known generalizations of the chemical effects of galvanism made by Hisinger and Berzelius; their experiments on the invisible transfer of elements at a distance, and the explanation given by Grotthus of the invisible transfer of the elements of water. Following this, Donovan alludes to the announced decomposition of muriatic acid by W. Peel, Francis Pacchiani, and others, as well as the discovery of the source of mistakes in the Galvani Society investigations by Pfaff, Biot, Thénard and Davy; after which reference is made to the special observations of Sylvester, Grotthus, Wilson, Erman, Davy, Pontin, Gay-Lussac and Thénard, Children, De Luc, Singer, Murray and Maycock.

On the 5th of April 1815, Donovan reviewed the hypotheses of Volta and Fabbroni, as well as of the British philosophers Wollaston, Bostock and Davy, and, on the 19th of the same month, he read an additional paper on the inadequacy of the galvanic hypothesis, having previously (Dec. 28, 1814, and Jan. 11, 1815) presented to the Kirwanian Society a communication relative to a new theory of Galvanism.

REFERENCES.--Phil. Mag., Vols. XXXIX. p. 396; XLIV. pp. 334, 401; XLV. pp. 154, 222, 308, 381; XLVI. p. 401; XLVII. pp. 167, 204; also Vol. XXXVII. pp. 227, 245, on Mr. Davy’s erroneous hypothesis of electro-chemical affinity, and Vols. XXII and XXIII of the Trans. Royal Irish Academy for Mr. Donovan’s papers relating to improvements in the construction of galvanometers, on galvanometric deflections, etc. etc.

=A.D. 1812.=--Zamboni (Giuseppe), Italian physicist, Professor of Natural Philosophy in the Verona Lyceum, makes known through his “Della pila elettrica a secco” an improved method of constructing dry piles. He dispenses entirely with the zinc plates of De Luc and employs only discs of paper having one side tinned and the other coated with a thin layer of black oxide of manganese pulverized in a mixture of flour and milk (“Note historique sur les piles sèches,” Annales de Chimie et de Physique, Vol. XI. p. 190).

His pile terminates in metallic plates, compressing the paper discs by means of silk ligatures, and the column is insulated by giving it a coating of either sulphur or shellac. In this apparatus the tinned surface is the positive element, the negative being the oxide of manganese, which replaces M. De Luc’s Dutch gilt paper. In the later forms of Zamboni’s pile the discs were formed of gilt and silvered paper pasted back to back. William Sturgeon remarks (“Scientific Researches,” Bury, 1850, p. 200) that the Zamboni piles are those which have been the most securely protected against the action of the ambient air and which alone have maintained their original electrical intensity.

REFERENCES.--Larousse, “Dict. Univ.,” Vol. XV. p. 1452; K. F. Anton Von Schreibers in Gilbert’s Annalen, LV; Placidus Heinrich (Schweigger’s Journal, XV); Gustav Schübler, “Uber Zamboni’s Trockne Säule,” 1815–1816; G. F. Parrot (Gilbert’s Annalen, LV); K. C. F. Jäger in Gilbert’s Annalen, Vol. XLIX for 1815, pp. 47–66; De la Rive, “Treatise on Electricity,” Vol. II. p. 852; A. M. Ampère, Ann. de Chimie et de Phys., XXIX; John Farrar, “Elem. of Electricity,” etc., 1826, p. 179; Zamboni and Ambrogio Fusinieri, Ann. ... Reg. Lomb., Veneto, Vols. IV. pp. 128, 132; VI. pp. 31, 142, 143, 293; G. Resti-Ferrari, “Elettroscopio ... del Zamboni”; Ann. ... Reg. Lomb., Ven., Vols. II. p. 229; III. p. 290; “Verona Poligrafo” for 1831, p. 87; Mem. Soc. Ital., Vols. XXI, XXIII; _Mem. dell’ Istit. Veneto_, Vol. II. pp. 239, 251; G. A. Majocchi, _Annali di Fisica_, Vol. VIII. p. 14; “Comm. dell’ Ateneo di Brescia,” 1832, p. 38; Sturgeon’s “Researches,” Bury, 1850, pp. 147, 199, etc., for observations of A. de la Rive and Francis Watkins; Phil. Mag., Vol. XLV. pp. 67, 261; Ann. Ch. et Phys. for May 1816, Vol. II. pp. 76, etc., 82–87, and Bibl. Britan., Vol. LVII. p. 225; also Vol. LVIII. p. 111 of the O.S., Vol. II, N.S. for 1816, p. 21 as well as Vol. XL. p. 190; “Bibl. Univ.,” Bruxelles, 1831, Vol. XLVII. p. 183 (horloge électrique); “Edin. New Phil. Journal,” 1829, Vol. XXI. p. 357. See likewise the references at Hachette (A.D. 1803), Dyckhoff (A.D. 1804), Maréchaux (A.D. 1806), De Luc (A.D. 1809); the illustration and description of M. Palmieri’s dry pile in Sci. Am. Supp., Nos. 512, 519, and the accounts of investigations made more particularly by MM. Beetz, Belgrado, Burstyn, Crosse, Du Bois Reymond, De la Rive, D’Arsonval, Desruelles, Edelmann, Faraday, Gassiot, Gassner, Germain, Roul, Guérin, Haussman, Keiser, Schübler, Minotto, Pollak, Riess, Schmidt, Trouvé, Wagner, Watkins and Wolf.

=A.D. 1812.=--Schilling (Pawel Lwowitch), Baron (of Kannstadt), attaché to the Russian Embassy in Munich, and who had been two years before associated with S. T. Von Sömmering (Kuhn, p. 836), devises what he calls his “sub-aqueous galvanic conducting cord”--a copper wire insulated with a thin coating of india-rubber and varnish. This was laid both underground and under the sea, and, it is asserted that, by means of an arrangement of charcoal points, he was enabled to explode powder mines across the Neva, near St. Petersburg, as well as also across the Seine, during the occupation of Paris by the allied armies.

REFERENCES.--Hamel, “Bull. Acad. Petersb.,” II and IV; also Wm. F. Cooke’s reprint, 1859, pp. 20–22; Fahie’s “History,” p. 309.

From the moment Schilling first saw the telegraph of Sömmering (Aug. 13, 1810) he made many experiments (Prime’s “Life of Morse,” p. 277) with the view of introducing it into Russia and finally took a model of it to St. Petersburg during the year 1812 (“Sc. Am. Suppl.,” No. 405). Hamel states (at p. 41 of Cooke’s reprint) that one of his contrivances was exhibited to the Emperor Alexander as early as 1825. Of this, Dr. E. N. Dickerson, in his Henry Memorial Address before Princeton College, gives the date as 1824. Be that as it may, it was only after his return from China in 1832 (two years after Sömmering’s death) that, following Ampère’s suggestion as to the availment of Oersted’s discovery, he submitted the apparatus which established for him the credit of having invented the electro-magnetic telegraph.

Many authors have erroneously described Schilling’s apparatus as consisting of a number of platinum wires insulated and bound together with a silken cord which put in motion thirty-six magnetic needles placed vertically in the centre of the multiplier by means of a species of key connecting with a galvanic pile. This account appeared at p. 43 of the “Journal des Travaux de l’Acad. de l’Industrie Française” for March 1839. The fact is that he employed but one magnetic needle and multiplier, with two leading wires, as proposed by Fechner, and was enabled by means of a combination of the deflections of the needle to the right and left to give all necessary signals for a complete correspondence by changing the poles of the battery at the ends of the wires. His call signal was given by a bell in connection with a clockwork, released by the deflection of a magnet.

REFERENCES.--For a detailed explanation of the working of Schilling’s telegraph, J. S. T. Gehler’s “Physikalisches Wörterbuch” for 1838, Vol. IX. p. 111; Fahie’s “History,” pp. 310–313; “Sc. Am. Suppl.,” No. 405, p. 6467.

From the account of the telegraphic collection at the 1873 Exposition, published by Dr. Edward Zetzsche in the “Austellungblatte” of the Vienna “Neue Freie Presse,” the following is extracted: “Even after Prof. Oersted, of Copenhagen, had observed the deviation of a magnetic needle under the influence of the current, neither the proposition of Ampère, at Paris, in 1820 (of employing thirty needles and sixty wires) nor that of Fechner, at Leipzig, in 1829 (twenty-four needles and forty-eight wires) gave any impulse to telegraphy. Only in 1832 did the Russian Councillor of State, Baron Schilling de Kannstadt (who had seen the telegraph of his friend Sömmering, and had made it known in Russia), invent a new instrument with but five wires, which number he subsequently reduced to one. In it, the movements of the needle were rendered more perceptible by means of little discs of paper attached to a silk thread, holding the needle in suspension. This telegraph, it is true, was not put in application on a large scale, for Schilling died in 1837, but, on the 23rd of Sept. 1835, he had already brought out his apparatus at Bonn and at Frankfort-on-the-Main, where it was seen amongst other persons by Prof. Muncke, who doubtless constructed a similar one which he took with him to Heidelberg.”

It was only one year before his death that Schilling succeeded in obtaining the support of the Russian Government for his telegraph, and it was only after Muncke had shown it (March 6, 1836) to Wm. Fothergill Cooke, then a student in medicine at Heidelberg, that the latter produced his needle telegraph, which was followed by Cooke and Wheatstone’s still more perfect instrument in 1837 (Prime’s “Life of Morse,” pp. 265, 276). Some improvements in Schilling’s so-called deflective telegraph had, in the meantime, been made by Gauss and Weber at Göttingen, as well as by Steinheil at Munich.

Prior to his visiting Bonn (Meeting of Naturalists--Isis, Nog., 1836) Schilling had taken the working model of his telegraph to Vienna, where he made many experiments with it in conjunction with Baron Jacquin and with Prof. Andreas von Ettinghausen. Upon his return home from Germany in 1836, he declined invitations made him to bring his instruments to England (Dr. Hamel’s St. Petersburg lecture on “The Telegraph and Baron Paul Schilling”), whilst, by direction of the Russian Commission of Inquiry, he set up an experimental telegraph in two chambers of the Palace of the Admiralty connecting the apparatus by a long line over ground and by a cable laid in the waters of the canal. The results proved so satisfactory that in May 1837 the Emperor Nicholas ordered a submarine line to be laid between St. Petersburg and Cronstadt. Schilling’s death, on the 25th of July following, prevented, however, the execution of the project.

REFERENCES.--Biography in Sci. Am. Supp., No. 547, p. 8737; Polytechnic Central Journal, Nos. 31, 32 for 1838; _Lumière Electrique_ for March 17, 1883; “Allg. Bauztg.,” 1837, No. 52, p. 440; L. Turnbull, Electro. Magn. Tel. p. 223; (Hibbard’s Ev. 31; Channing, Ev. 41); Poggendorff, Vol. II. p. 798; Annales Télégraphiques for November to December 1861, p. 670; Journal Soc. of Arts for July 22, 1859, p. 598; References at Ronalds’ “Catalogue,” p. 457; Du Moncel, “Exposé,” Vol. III. p. 8 and “Traité Théorique et Pratique du Tel. Elect.,” Paris, 1864, p. 217; Comptes Rendus, Vol. VII for 1838, p. 82; Journal Franklin Inst. for 1851, p. 60; H. F. E. Lenz, “Uber die Praktische ... Galvanismus,” 1839; “Report of Smithsonian Inst.,” 1898, pp. 224–225.

=A.D. 1812–1813.=--Morichini (Domenico Pini), eminent Italian physician, is the first to announce that unmagnetized steel needles can be rendered magnetic by making the focus of violet solar rays collected through a lens pass repeatedly from the middle to one end of the needle, without touching the other half (Zantedeschi, II. p. 214).

The long contention created by this announcement and the ingenious experiments of Mrs. Somerville, together with the results obtained by P. T. Riess and L. Moser, are detailed at p. 48 of Brewster’s (1837) “Treatise on Magnetism.” At p. 12 of his article (Vol. XIV of the eighth “Britannica”), Sir David Brewster states that Morichini’s experiments were successfully repeated by both Dr. Carpi at Rome and the Marquis Ridolfi at Florence; but M. d’Hombre Firmas, at Alais, in France; Prof. Pietro Configliachi, of Pavia, and M. Berard, of Montpelier, failed in obtaining decided effects from the violet rays. In 1814 Morichini exhibited the actual experiment to Sir Humphry Davy, and in 1817 Dr. Carpi showed it to Prof. Playfair. A few months later Sir David Brewster met Davy at Geneva, and learned from him the fact that he had paid the most diligent attention to one of Morichini’s experiments, and that he had actually seen with his own eyes an unmagnetized needle rendered magnetic by violet light. Then follow in the same article the account of Dr. Carpi’s experiment as given to Brewster by Prof. Playfair, also details of the investigations of Mrs. Somerville, Mr. Christie, Sir William Snow Harris, Prof. Zantedeschi, of MM. Baumgartner and Barlocci, as well as those of Riess and Moser above alluded to.

REFERENCES.--“Elogio storico del Cavaliere D. Morichini” in Mem. della Soc. Ital., Vol. XXVI. p. 3; Riess and Moser in Phil. Mag. or Annals, Vol. VIII. p. 155, 1830 and in Edin. Trans., Vol. X. p. 123; “Library of Useful Knowledge” (El. Mag.), p. 97; Zeitschrift, Vol. I. p. 263; Noad, “Manual,” pp. 532, 533; the article of Col. George Gibbs in Silliman’s _Amer. Jour. of Sci._, 1818, Vol. I. pp. 89, 90; Annales de Chimie, Vol. XLII. p. 304; Brewster’s “Optics,” p. 92; also articles “Optics,” p. 596, “Light,” p. 452 and “Electricity,” p. 569 of the eighth “Britannica”; Edin. Jour. of Sci., No. 4, p. 225; B. Gandolfi, “Antologia Romana,” 1797; Harris, “Rud. Mag.,” Parts I, II. p. 69; Phil. Trans. for 1826, pp. 132, 219; D. Olmstead, “Int. to Nat. Phil.,” 1835, Vol. II. p. 194. See also Thomas Thomson’s “Outline of the Sci.,” p. 514, and Berzelius’ “Traité de Chimie,” Vol. I. p. 138 for Morichini’s observations on galvanic energy; “Bibl. Brit.,” Vol. LII, 1813, p. 21; Vol. LIII, 1813, p. 195; Vol. LIV, 1813, p. 171 (Experiments of G. Babini in Florence); Vol. IV, N.S., 1817, pp. 1–8; Vol. V, N.S., 1817, p. 167; Vol. VI, N.S., 1817, p. 81; Vol. XI, N.S., 1819, p. 29 for the experiments of L. A. d’Hombre Firmas on Morichini’s violet rays, whilst p. 174 of the same issue gives J. Murray’s investigations as recorded in the “Phil. Mag.” for April 1819.

Peter (Pietro) Configliachi, already named, was the successor of Volta as Professor of Natural Philosophy at the Pavia University, and became editor of the “Biblioteca Fisica d’Europa,” the “Biblioteca Germanica,” the “Biblioteca Italiana” and the “Giornale di Fisica, Chimica e Storia Naturale” (Larousse, “Dict. Univ.,” Vol. IV. p. 908; J. J. Prechtl, in Schweigger’s Journal, Vol. IV for 1812; Fr. Mochetti, “Lettera al P. Configliachi,” Como, 1814; “Bibl. Britan.,” Vol. LVIII, 1815, p. 305 and Vol. IV of the N.S. for 1817, pp. 1–8).

=A.D. 1813.=--Sharpe (John Robert), of Doe Hill, near Alfreton, transmits to the Repertory of Arts a letter, which appeared in its Vol. XXIX, second series, p. 23, wherein he alludes to p. 188, Vol. XXIV of the same series, containing an account of Sömmering’s apparatus. He says:

“Without the slightest wish to throw a doubt over the originality of Mr. Sömmering’s invention, I beg leave to mention that an experiment, showing the advantages to be obtained from the application of the certain and rapid motion of the electric principle through an extensive voltaic circuit to the purpose of the ordinary telegraph, was exhibited by me before the Right Hon. the Lords of the Admiralty, in the beginning of February 1813.”

It is said that the Lords of the Admiralty spoke approvingly of it, but stated that as the war was over, and money scarce, they could not carry it into effect (Saturday Review for August 21, 1858, p. 190).

Ronalds says (“Catal.,” p. 473):

“No description of this telegraph appears to have been printed. It was mentioned at the Admiralty after the invention and full description of Sömmering’s, described fully and with figures in the Denkschriften of the Academy of Munich for 1809–1810, issued in 1811.”

Mr. Benjamin Sharpe, nephew of J. R. Sharpe, is the author of “A Treatise on the Construction and Submersion of Deep-Sea Electric Telegraph Cables,” London, 1861, wherein he alludes to the above, and asserts that his uncle “conveyed signals a distance of seven miles under water” (Fahie’s “History,” pp. 244–246; Sci. Am. Supp., No. 404, pp. 6, 446).

=A.D. 1813.=--Deleuze (Joseph Philippe François), French physician, publishes his “Histoire Critique du Magnétisme Animal,” containing the result of observations made by him during the previous twenty-five years upon animal magnetism.

According to Dr. Allen Thomson, of the University of Glasgow, Deleuze believed in the existence of an all-pervading magnetic fluid. This fluid, says he, is under the control of the will, and is constantly escaping from our bodies, forming around them an atmosphere, which, having no determinate current, does not act sensibly on the person near us; but, when urged and directed by our volition, it moves with all the force which we impress upon it; it is moved like the luminous rays emitted by substances in a state of combustion. The chief difference between the Deleuze and Puységur schools has reference to the various modes in which the magnetic fluid should be brought into action, and the suitable occasions for its employment.

During the year 1815 the Magnetic Society was established in Paris, with M. De Puységur as its president and M. Deleuze as vice-president, but it expired in 1820. In 1819 M. Deleuze had published his “Défense du Magnétisme Animal,” in reply to the attack made upon the subject by M. Virey through the “Dictionnaire des Sciences Médicales,” and he was followed, more particularly, by M. Bertrand, who issued in 1823 his “Traité du Somnambulisme,” and in 1826 his still more important work, “Du Magnétisme Animal en France,” etc. Respecting the last named Deleuze says:

“Of all the attacks directed against magnetism up to the present day, this is the most powerful, the most imposing, and the most ably combined. The author is a man of genius, etc. He has been occupied with magnetism for some years. He has joined its practice to that of medicine, and he has even taught its doctrines in public lectures. A more attentive examination and new experiments have dissuaded him from a belief which he himself propagated; he undertakes to undeceive others, and to prove that magnetism is a mere chimera. Certainly his conviction must be very strong.”

REFERENCES.--Article “Somnambulism,” in the “Britannica,” more especially for a review of, and extracts from, Deleuze’s great work, also the translation of the latter by T. C. Hartshorn, of which the enlarged fourth edition was published at London in 1850, accompanied by notes and a life by Dr. Foissac.

=A.D. 1813.=--Brande (William Thomas), F.R.S., succeeds Sir Humphry Davy as Professor of Chemistry to the Royal Institution after having long been his assistant.

He was already favourably known through a long line of interesting chemical experiments, one of which, treating of the effects of the galvanic current on albumen, had attracted very particular attention at the time it was communicated to the Philosophical Transactions. When he applied Davy’s method to fluids containing albumen, the albumen and acid were found at the positive pole and the albumen and alkali at the negative pole, and he also observed that, although it remained fluid with a weak battery, a stronger one caused it to be separated in a coagulated form. In like experiments subsequently made by Golding Bird, coagulation took place in the positive vessel, while none occurred in the negative; after a time the contents of the former had an acid taste, and of the latter a caustic alkaline flavour. When all in the positive vessel was coagulated by the galvanic action, he found there hydrochloric acid mixed with chlorine and the alkali in the negative vessel.

He also repeated the experiments of Davy on the light developed by charcoal points connected with a powerful galvanic battery, and found that this light was as effectual as solar light in decomposing muriate of silver and other bodies, and in acting upon hydrogen and chlorine gases, causing them to detonate, but he could not produce the same effect by the moon’s rays or by any other light.

The electricity developed in flame, which had received much attention from Paul Erman and others, was likewise investigated by Prof. Brande, whose conclusions are to be found detailed at Sec. III. chap. iii. part i. of the “Electricity” article in the “Encyclopædia Britannica.” Therein is recalled the fact that A. L. Lavoisier, P. S. Laplace and Aless. Volta previously obtained clear indications of electricity by the combustion of charcoal, while H. B. de Saussure failed to develop electricity either by the combustion or explosion of gunpowder, and Humphry Davy could not obtain it through the combustion of charcoal or of iron in air or in pure oxygen. In the above-named article will also be found an account of the investigations of Pouillet and of Becquerel in the same line; some of the other well-known scientists who have treated more or less directly upon the subject being E. F. Dutour, J. S. Waitz, J. J. Hemmer, Heinrich Buff, G. Gurney, Carlo Matteucci, W. R. Grove, Michael Faraday, M. A. Bancalari, W. G. Hankel, F. Zantedeschi and M. Neyreneuf.

REFERENCES.--Phil. Mag., Vol. XLIV. p. 124; _Phil. Mag. or Annals_, Vol. IX. p. 237; Annales de Chimie, 5^e série, Vol. II; Phil. Trans. for 1809 and 1820; _Mémoires de Mathématiques_, Vol. II. p. 246; “Cat. Sc. Pap. Roy. Soc.,” Vol. I. p. 48; “Bibl. Britan.,” Vol. LVII, 1814, p. 11.

=A.D. 1813.=--Colonel Mark Beaufoy (already alluded to at Graham, A.D. 1722), describes in the first volume of Dr. Thomas Thomson’s Annals of Philosophy what has by many been called the most perfect form known of the variation compass. It is also to be found illustrated at p. 81, Vol. XIV of the eighth “Britannica,” wherein it is said that he employed it in the valuable series of magnetic observations made by him between the years 1813 and 1821. It consists of a telescope, underneath the axis of which is a magnetic needle whose position is alterable in order to indicate the exact angle of deviation, or the declination of the needle from the true meridian.

Brewster states (eighth “Brit.,” Vol. XIV. p. 54) that when the diurnal variation of the needle was first discovered it was supposed to have only two changes in its movements during the day. About 7 a.m. its north end began to deviate to the west, and about 2 p.m. it reached its maximum westerly deviation. It then returned to the eastward to its first position, and remained stationary till it again resumed its westerly course in the following morning. When magnetic observations became more accurate, it was found that the diurnal movement commences much earlier than 7 a.m., but its motion is to the east. At 7.30 a.m. it reaches its greatest easterly deviation, and then begins its movement to the west till 2 p.m. It then returns to the eastward till the evening, when it has again a slight westerly motion; and in the course of the night, or early in the morning, it reaches the point from which it set out twenty-four hours before. The most accurate observations made in England were those of Colonel Beaufoy, when the variation was about 24½´ west. In these the absolute maxima were earlier than in Canton’s observations, and the second maximum west about 11 p.m. Dr. Thomas Thomson alludes to the diurnal investigations of Barlow and Christie and others, and gives (“Outline of the Sciences,” London, 1830, pp. 543–550) a table of the mean monthly variation of the compass from April 1817 to March 1819 as determined by Colonel Beaufoy. Mr. Peter Barlow, he says, has given in his “Essay on Magnetic Attractions” a very ingenious and plausible explanation of the daily variation by supposing the sun to possess a certain magnetic action on the needle.

REFERENCES.--Phil. Mag., Vol. LIII, 1819, p. 387; LV, 1820, p. 394; W. S. Harris, “Rud. Mag.,” Parts I, II, pp. 150–152; “Encycl. Metrop.,” Vol. III (Magnetism), pp. 766, 767; Annals of Phil., series 1, Vols. II, VI, IX, XVI, and N.S., Vol. I. p. 94, for Beaufoy’s own summary of all his observations.

=A.D. 1814.=--Mr. Thomas Howldy addresses to the Philosophical Magazine a letter, dated Hereford, March 24, 1814, relative to “Experiments evincing the influence of atmospheric moisture on an electric column composed of 1000 discs of zinc and silver,” wherein he also makes reference to the dry pile of J. A. De Luc alluded to at A.D. 1809.

REFERENCES.--Phil. Mag., Vol. XLIII. pp. 241, 363, and Nicholson’s Journal, Vol. XXXV. p. 84; also the Phil. Mag., Vol. XLI. p. 393, for a description of the electric column of 20,000 pairs of zinc and silver plates, and others, constructed during the previous year (1813) by Mr. George J. Singer.

The above-named letter was followed (Phil. Mag., Vols. XLVI. pp. 401–408, and XLVII. p. 285) by a communication on the “Franklinian Theory of the Leyden Jar ... with Some Remarks on Mr. Donovan’s Experiments,” and by another letter sent to MM. R. Taylor and R. Phillips (Phil. Mag. or Annals, Vol. I. p. 343) relative to the paper of William Sturgeon “On the Inflammation of Gunpowder by Electricity,” which appeared at p. 20 of the last-named book.

An interchange of correspondence not long since through the columns of the London Electrical Review, for the purpose of ascertaining the period of the earliest use of carbon as a resistant, brought forth an extract from the “Treatise on Atmospheric Electricity,” published at London and Edinburgh, 1830, by Mr. John Murray, of Glasgow, which reads as follows: “Mr. Howldy, of Hereford, an ingenious electrician, has by some novel experiments clearly proved the increased power of electricity if retarded in its progress; instead of using tubes of glass filled with water, as Mr. Woodward had done, he has employed a glass tube supplied with lamp black.”

=A.D. 1814.=--Murray (John), Scotch physician and chemist, also Ph.D., and Professor of Chemistry and Materia Medica in the Edinburgh University, is the author of works entitled, “On Electrical Phenomena, and on the new substance called Jod (Iode),” also “On the Phenomena of Electricity,” published at London, respectively, during the years 1814 and 1815 (Tilloch’s Phil. Mag., Vols. XLIII. pp. 270–272; XLV. pp. 38–41; “Catalogue Sci. Pap. Roy. Soc.,” Vol. IV. pp. 556–557).

Dr. John Murray died July 22, 1820, in Edinburgh, the place of his birth, as will be seen by reference to Larousse, “Dict. Univ.,” Vol. XI. p. 706, and to Poggendorff, Vol. II. pp. 243, 244. He should not be confounded, as has been done by many, with Mr. John Murray, whose papers, read before the Royal Society (“Catalogue Scientific Papers,” Vol. IV. pp. 557–559; Vol. VI. p. 731), treat of the relations of caloric to magnetism, of the unequal distribution of caloric in voltaic action, etc., of aerolites, of the decomposition of metallic salts by the magnet, of the ignition of wires by the galvanic battery, of lightning rods, conductors, etc. (These papers appear in Tilloch’s Phil. Mag., Vols. LIV, 1819, pp. 39–43; LVIII, 1821, pp. 380–382; LX, 1822, pp. 358–361; LXI, 1823, p. 207; LXII, 1823, p. 74; LXIII, 1824, pp. 130, 131; L. F. von Froriep, “Notizen ...” for 1823, Vol. IV. col. 198; Edin. Phil. Jour., Vols. XIV for 1826, pp. 57–62; XVIII for 1828, pp. 88–91; and in Sturgeon’s Annals, Vols. III for 1838–1839, pp. 64–68; VII for 1841, pp. 82–83.)

Mr. John Murray is said to have been a lecturer on experimental philosophy, and one of his most interesting reviews is the one appearing at p. 62, Vol. XLIII of the Phil. Mag. regarding Ezekiel Walker’s theory of combustion as deduced from galvanic phenomena. Murray thinks there is much obscurity in Mr. Walker’s solution, which arises “from his using indiscriminately the terms heat (caloric) and combustion. Now caloric (the matter of heat) and combustion (the act of ignition) are not identical. What may be collected, however, from the general tenor of that paper is the theory of Lavoisier in a new dress.”

At p. 17 of this same volume is a paper from Mr. John Webster on the agency of electricity in contributing the peculiar properties of bodies and producing combustion, while, at p. 20, is a letter from Mr. George J. Singer wherein he calls Mr. Walker a novice in the science of electricity, saying that among other things he “has yet to learn that a conducting body supported by dry glass and surrounded by dry air may be still very far from being insulated.”

The treatise of Mr. John Murray on “Atmospheric Electricity” previously alluded to (at Thomas Howldy, A.D. 1814) was translated into French (“Mém. de l’Elec. Atm.”) by J. R. D. Riffault, Paris, 1831.

REFERENCES.--Phil. Mag., Vols. XLIII. p. 175; L. pp. 145, 312; LII. p. 60; LIII. pp. 268, 468; LVIII. p. 387; LX. p. 61; LXI. p. 394; LXII. p. 456; LXIII. p. 130; also pp. 306, 307 of Fahie’s “History,” regarding John Murray’s “Notes to Assist the Memory in Various Sciences.”

=A.D. 1814.=--Wedgwood (Ralph), member of the family whose name is inseparably connected with one of the most beautiful manufactures of pottery, completes an electric telegraph, upon which he has been steadily at work from 1806. Of its construction or mode of action he appears, however, to have left no particulars.

At pp. 178 and 180 of “The Wedgwoods ...” by Llewellyn Jewett, London, 1865, appears the following:

“This Thomas Wedgwood was, I believe, cousin to Josiah, being son of Aaron Wedgwood, etc., etc. ... He was a man of high scientific attainments, and has the reputation of being the first inventor of the electric telegraph (afterward so ably carried out by his son Ralph) and of many other valuable works.... In 1806 Ralph Wedgwood established himself at Charing Cross, and soon afterward his whole attention began to be engrossed with his scheme of the electric telegraph, which in the then unsettled state of the kingdom--in the midst of war, it must be remembered--he considered would be of the utmost importance to the government. In 1814, having perfected his scheme, he submitted his proposals to Lord Castlereagh, and most anxiously waited the result ... was informed that ‘the war being at an end, the old system was sufficient for the country.’ The plan, therefore, fell to the ground, until Prof. Wheatstone, in happier and more enlightened times, again brought up the subject with such eminent success. The plan thus brought forward by Ralph Wedgwood, in 1814, and of which, as I have stated, he received the first idea from his father, was described by him in a pamphlet, entitled ‘An Address to the Public on the Advantages of a Proposed Introduction of the Stylographic Principle of Writing Into General Use; And Also an Improved Species of Telegraphy, Calculated for the Use of the Public, as Well as for the Government.’”

The pamphlet is dated May 29, 1815. Fahie gives (“History,” pp. 125–127) extracts both from this pamphlet, regarding the electric Fulguri-Polygraph, and from the communication of Mr. W. R. Wedgwood to the Commercial Magazine for December 1846, urging his father’s claims to a share in the discovery of the electric telegraph.

REFERENCES.--“Life of Wedgwood,” by Miss Meteyard, 2 vols., 1865–1866; J. D. Reid, “The Telegraph in America,” p. 70.

=A.D. 1814.=--Singer (George John), distinguished English scientist and writer, publishes the first edition of his valuable “Elements of Electricity and Electro-Chemistry,” of which translations were made, in French by M. Thillaye, Paris, 1817, as well as in German and in Italian during the year 1819.

Mr. Singer is the inventor of the improvement upon Mr. Bennet’s electroscope, which is to be found illustrated and described in nearly all works upon natural philosophy and the main design of which is to diminish, if not totally prevent, the amount of moisture generally precipitated upon the surface of insulators. Mr. Singer remarks that his arrangement so effectually precludes moisture that some of the “electrometers constructed in 1810 and which have never yet (1814) been warmed or wiped, have still apparently the same insulating power as at first.” The use of this apparatus is strongly recommended by Dr. Faraday, whose instructions for the use of electrometers are given at great length at pp. 617–619, Vol. VIII of the eighth “Britannica.”

After describing the above-named electrometer, Mr. William Sturgeon remarks (“Lectures,” London, 1842, pp. 42, 43):

“It is frequently exceedingly difficult, without extensive reading, to confer the merit that is due to invention on the right party, and even then we sometimes err for want of proper information. Mr. Singer has hitherto, with most writers, had the exclusive merit of insulating the axial wire of the electroscope from the brass cap, by a glass tube; and it would appear from the description he gives of this improvement in his excellent treatise on electricity that he was not aware of anything of the kind being previously done. It appears, however, by an article of Mr. Erman in the Journal de Physique, Vol. LIX. p. 98, and Nicholson’s Journal, Vol. X, published in 1805, that a Mr. Weiss had applied the glass tube for the purpose of insulating the axial wire of Bennet’s electroscope. The account runs thus: ‘The electrometer he (Mr. Erman) used was that distinguished in Germany as the electrometer of Weiss.’ From this it would appear to have been long known. ‘The length of its leaves of gold is half an inch, and the diameter of the glass cylinder which encloses them is three-quarters of an inch, the height being an inch and a half. Its cover of ivory does not project above the glass, and is perforated in the middle with a hole in which a smaller glass tube is fixed, and through this last tube passes the metallic rod that serves to suspend the gold leaves.’ Singer’s improvement, first published in 1814, would, therefore, consist in adding the brass ferrule, which covers the glass tube first introduced by Weiss.”

Singer is also the inventor of one of the best-known amalgams for the cushions of the electric machine. It is described at p. 536, Vol. VIII of the eighth “Britannica,” where it is said that a mixture of one part tin and two parts mercury is very effective, as is also the amalgam consisting of mosaic gold and the deutosulphuret of tin. (Other descriptions of the application of mosaic gold on the rubber are to be found at p. 432, Vol. II of “Young’s Course of Lectures”; Woulfe, Phil. Trans., 1771, p. 114; Bienvenu and Witry de Abt, Lichtenb. Mag., Vols. II. p. 211, and IV. st. 3, pp. 58–61; Marquis de Bouillon, “Observ. de Physique,” XXI.)

The dry electric columns which Mr. Singer invented are alluded to in Phil. Mag., Vols. XLI. p. 393 and XLV. p. 359, while the results of his experiments on the electric fusion of metallic wires and the oxidation of metals, as well as those made upon the electricity of sifted powders and also in order to ascertain the effects of electricity upon gases, are to be found recorded at pp. 564, 592, 593 and 597, Vol. VIII of the 1855 “Britannica,” and at p. 46 (“Electricity”) of “Library of Useful Knowledge.”

REFERENCES.--pp. 15, 16 of the last-named work; Poggendorff, Vol. II. pp. 938, 939; Figuier, “Exp. et Hist.,” 1857, Vol. IV. p. 267; Sturgeon’s “Lectures,” 1842, p. 11; Phil. Mag., Vols. XXXVII. p. 80; XLII. pp. 36, 261; XLIII. p. 20; XLVI. pp. 161, 259; likewise Ch. Samuel Weiss, at Poggendorff, Vol. II. pp. 1287–1289; “Bibl. Britan.,” Vol. XLIII, 1810, p. 166; Vol. XLVII, 1811, pp. 3, 113, 213, 313; Vol. LVI, 1814, pp. 197, 318.

=A.D. 1814–1815.=--Fraunhofer--Frauenhofer (Joseph von), a practical Bavarian physicist and optician, who had been assistant to the celebrated George Reichenbach, publishes his observations on spectra in a pamphlet entitled “Bestimmung des Brechungs und Farbenzerstreuungs-Vermögens ...”

In the latter work will be found detailed his experiments with the electric spark, which he found to give a different spectrum from all other lights. Sir David Brewster says that in order to obtain a continuous line of electrical light Fraunhofer brought to within half an inch of each other two conductors, and united them by a very fine glass thread. One of the conductors was connected with an electrical machine and the other communicated with the ground. In this manner the light appeared to pass continuously along the fibre of glass, which consequently formed a fine and brilliant line of light. When this luminous line was expanded by refraction, Fraunhofer saw that, in relation to the lines of its spectrum, electric light was very different both from the light of the sun and from that of a lamp. In this spectrum he met with several lines partly very clear, and one of which, in the green space, seemed very brilliant compared with other parts of the spectrum (Edin. Jour. of Sci., No. XV. p. 7). He saw in the orange another line not quite so bright, which appeared to be of the same colour as that in lamplight spectra; but in measuring its angle of refraction he found that its light was much more strongly refracted, and nearly as much as the yellow rays of lamplight. In the red rays toward the extremity of the spectrum, he observed a line of very little brightness, and yet its light had the same degree of refrangibility as the clear line of lamplight, while in the rest of the spectrum he saw the other four lines sufficiently bright. In a subsequent paper read at Munich in 1823 (“Neue Modifikation des Lichtes ...” or “New Modification of Light”) and in Schumacher’s “Astronomische Abhandlungen,” Fraunhofer states that, by means of the large electrical machine in the cabinet of the Academy of Munich, he obtained a spectrum of electric light in which he recognized a great number of light lines, and that he had determined the relative place of the lightest lines as well as the ratios of their intensities.

The introduction of the electric spark for the purpose of volatilizing metals was an important step in the development of spectral analysis, but although used by both Wollaston and Fraunhofer its true value in that particular line was not realized for many years after their time.

Fraunhofer is not only celebrated as one of the founders of spectrum analysis, but he is well known also as the inventor of many important philosophical instruments, being the constructor of the great Dorpat parallactic telescope, called by Struve the giant refractor. It was during the year 1814 that he measured and described the innumerable dark lines of the solar spectrum known as Fraunhofer’s lines, which were first noticed by Wollaston and reported upon by the latter to the Royal Society in 1802.

REFERENCES.--M. Merz, “Das Leben und Wirken Fraunhofers,” Landshut, 1865; Ninth “Encycl. Brit.,” Vol. IX. p. 727; “Abh. der K. Bayer, Akad. d. Wiss.” for 1814 and 1815; Fraunhofer’s biography in the “Memoirs of the Astronomical Society of London,” Vol. III. p. 117; his “Determination ...” München, 1819; Whewell, “Hist. of Ind. Sci.,” 1859, Vol. II. p. 475; Sci. Am., Nov. 19, 1887, p. 321; Phil. Trans. for 1814, pp. 204, 205, and for 1820, p. 95; Tyndall, “Heat as a Mode of Motion,” 1873, pp. 485, 486; article “Optics” in eighth “Encycl. Brit.,” Vol. XVI. pp. 544, 588, 591; Sir David Brewster’s article on “Electricity” in the “Encycl. Brit.”; “Mem. of the Roy. Bav. Acad. of Sci.” for 1822; “On the Spectrum of the Electric Arc,” in Jas. Dredge’s “Elec. Illum.,” Vol. I. pp. 32, 36; Edin. Trans., Vol. VIII for 1822; Edin. Jour. Sci., Vol. XIII. pp. 101, 251; Biblioth. Univ., Vol. VI. p. 21, as per Becquerel’s “Traité ...” Vol. I. p. 23; Dr. William A. Miller’s first and third lectures before the Royal Institution in 1867; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 136; Rich. A. Proctor, “Old and New Astronomy,” 1892, p. 787.

=A.D. 1815.=--Bohnenberger (Johann Joseph Friedrich von), 1765–1831, Professor of Mathematics and of Astronomy at the Tübingen University, constructs an extremely sensitive electrometer by suspending a single strip of gold leaf upon a wire midway between, though apart from, the insulated terminating discs of De Luc’s column.

With this contrivance he found that, however slightly the leaf was electrified, it was drawn to one of the poles according to the nature of the electricity affecting it, and he was thus enabled to observe not only the presence of the slightest electrical influence, but the kind of electricity which was present.

Noad gives, at p. 30 of his “Manual,” an illustration of the electrometer as subsequently improved by Becquerel, and states that Mr. Sturgeon describes (“Lectures on Galvanism,” 1843) a somewhat similar arrangement, the delicacy of which he states to be such that the cap (plate) being of zinc and of the size of a sixpence, the pendant leaf is caused to lean toward the negative pole by merely pressing a plate of copper, also the size of a sixpence, upon it, and when the copper is suddenly lifted up the leaf strikes. The different electrical states of the inside and outside of various articles of clothing were readily ascertained by this delicate electroscope.

M. Gottlieb Christian Bohnenberger, of Neuenberg (1732–1807), is the author of several works treating particularly of the electrical machine, the electric spark, the electric doubler, etc., published at Stuttgart between 1784 and 1798.

REFERENCES.--“La Grande Encyclopédie,” Vol. VII. p. 84; L. W. Gilbert, Annalen der Physik, Vols. XXIII (for Behrend’s); XLIX, LI (for “Beschreibung ... empfindlichen elektrometers ...”); Annales de Chimie et de Physique, Vol. XVI. p. 91; J. C. Poggendorff, “Biogr.-Liter. Handwörterbuch ...” Vol. I. p. 226; Sci. Am. Supp., No. 519, p. 8290, for Pouillet’s remarks upon the effectiveness of dry pile electroscopes; De la Rive, “Treatise on Electricity,” Vol. I. pp. 54–56.

=A.D. 1815.=--Mr. B. M. Forster sends to the Philosophical Magazine (Vol. XLVII. pp. 344–345) the description of an electrical instrument called “The Thunderstorm Alarum,” which can be made to show the effect produced by the passage of a charged cloud over an atmospherical electrometer.

He had several years before described, at p. 205 of the same publication, a method of fitting up in portable form one of De Luc’s electrical columns, respecting which latter he subsequently addressed communications, which appeared in Vols. XXXV. pp. 317, 399, 468; XXXVI. pp. 74, 317, 472; XXXVII. pp. 197, 265, also relative to one which he constructed and which ran continuously for five months.

REFERENCES.--Phil. Mag., Vol. IV for 1828, p. 463; eighth “Britannica,” Vol. XXI. p. 619.

=A.D. 1815.=--Gregory (Olinthus Gilbert), LL.D., Professor of Mathematics at the Royal Military Academy, Woolwich, in his “Treatise on Mechanics,” London, 1815 (Vol. II. pp. 442–449), describes the methods of transmitting distant signals introduced by Polybius, the Marquis of Worcester, Robert Hooke, Amontons and Chappe, and alludes to an improved telegraph described in the “Gentleman’s Magazine,” as well as to the so-called nocturnal telegraph, of which an account is to be found in the Repertory of the Arts and Manufactures (“Biographie Générale,” Tome XXI. p. 903).

=A.D. 1815.=--In the Philosophical Magazine (Vol. XLVI. pp. 161, 259), will be found an account of the electrical experiments of M. De Nelis, of Mechlin, or Malines, in the Netherlands, with an extension of them by George J. Singer and Andrew Crosse.

These allude to many investigations made during previous years by M. De Nelis, who reported upon them to Mr. Tilloch and to M. de la Méthérie, and which show “very remarkable and permanent evidence of the expansive power of the electric charge.” Singer adds: “It is difficult to contemplate such extraordinary mechanical effects without admitting that the power by which they are produced has at least the leading characteristics of a material substance.” At p. 127, Vol. XLVIII of the Phil. Mag., is an account of some further electrical experiments of M. De Nelis, one of which is intended to improve the simple current with an apparatus not insulated by discs. In this communication, which bears date July 10, 1815, he discourses upon the theory of the two fluids.

=A.D. 1816.=--Coxe (John Redman), M.D., Professor of Chemistry in the University of Pennsylvania, is the second to propose a system of transmitting signals, based, like Sömmering’s (A.D. 1809), upon the discovery of Nicholson and Carlisle.

In the first series of Dr. Thos. Thomson’s Annals of Philosophy for 1816 (not 1810), Vol. VII. pp. 162, 163, will be found Coxe’s letter “On the Use of Galvanism as a Telegraph,” wherein he says:

“I have contemplated this important agent as a probable means of establishing telegraphic communication with as much rapidity, and perhaps less expense, than any hitherto employed. I do not know how far experiment has determined galvanic action to be communicated by means of wires; but there is no reason to suppose it confined as to limits, certainly not as to time. Now, by means of apparatus fixed at certain distances, as telegraphic stations, by tubes for the decomposition of water, metallic salts, etc., regularly arranged, such a key might be adopted as would be requisite to communicate words, sentences or figures, from one station to another, and so on to the end of the line.... As it takes up little room, and may be fixed in private, it might in many cases of besieged towns, etc., convey useful intelligence with scarcely a chance of detection by the enemy. However fanciful in speculation, I have no doubt that, sooner or later, it will be rendered in useful practice. I have thus, my dear sir, ventured to encroach on your time with some crude ideas that may serve perhaps to elicit some useful experiments in the hands of others. When we consider what wonderful results have arisen from the first trifling experiments of the junction of a small piece of silver and zinc in so short a period, what may not be expected from the further extension of galvanic electricity? I have no doubt of its being the chief agent in the hands of nature in the mighty changes that occur around us. If metals are compound bodies, which I doubt not, will not this active principle combine their constituents in numerous places so as to explain their metallic formation; and if such constituents are in themselves aeriform, may not galvanism reasonably tend to explain the existence of metals in situations in which their specific gravities certainly do not entitle us to look for them?”

Coxe does not appear, however, to have at any time made satisfactory experiments, and his systems were considered impracticable until worked out by Alex. Bain during the year 1840.

At pp. 99–110, Vol. II of Dr. Coxe’s Emporium of Arts and Sciences, Philadelphia, 1812, will be found his illustrated “Description of a Revolving Telegraph,” for conveying intelligence by figures, letters, words or sentences, upon which plan, he says, he constructed a small telegraph that worked “readily and appropriately, although by no means fitted with the various pulleys, etc., to facilitate the motion of the ropes.”

REFERENCES.--For full explanation of Coxe’s systems, see L. Turnbull, “Elect. Mag. Tel.” Highton’s “Electric Telegraph,” p. 39; Jour. Franklin Inst., Vol. XXI. for 1851, pp. 332, 333; Comptes Rendus for 1838, Vol. VII. pp. 593, etc.; Sci. Am. Supp., Nos. 404, p. 6446, and 453, p. 7234; Alfred Vail, “The American Electro-Magnetic Telegraph,” pp. 128, 129; Prime’s “Life of Morse,” p. 263.

=A.D. 1816.=--In Part I of the Philosophical Transactions for 1816, and at p. 14, Vol. XLVII of the Philosophical Magazine, will be seen an account of the observations and experiments made by Mr. John T. Todd on the torpedo off the Cape of Good Hope, during the year 1812 (“Abstracts of Papers ... Roy. Soc.,” Vol. II. p. 57).

It is said that the torpedo in this locality is never more than eight nor less than five inches in length, and never more than five nor less than three and a half inches in breadth. Mr. Todd found the columns of their electrical organs to be larger and less numerous in proportion than those described by Hunter, and that they appeared to be of a cylindrical form, while from a number of experiments he drew, among other conclusions, the fact that a more intimate relation exists between the nervous system and electrical organs of the torpedo, both as to structure and functions, than between the same and whatsoever organs of any known animal. (See Hunter at A.D. 1773.)

Reports of another series of experiments, carried on by Mr. Todd at La Rochelle during 1816, will be found in the Phil. Trans. for the year following as well as at p. 57, Vol. II of the “Abstracts of Papers ... of the Phil. Trans., 1800–1830.” The last-named investigations were made especially to determine whether the torpedo possessed any voluntary power over the electrical organs, either in exciting or interrupting their action, except through the nerves of these organs.

=A.D. 1816.=--Philip--Phillip--(Wilson), English physician, publishes in the Philosophical Transactions a continuation of researches made by him to establish the relations existing between the phenomena of life and voltaic electricity. Noad gives (“Manual,” pp. 341–344) an account of some of the experiments made on animals to prove the analogy existing between the galvanic energy and the nervous influence, and he alludes also to the fact of asthma having been relieved by galvanism through Dr. Philip, whose treatment had received the endorsement of Dr. Clarke Abel, of Brighton.

REFERENCES.--Journal of Science, Vol. IX. See also Faraday’s “Experimental Researches,” 1791 and note; “Abstract of Papers ... Phil. Trans., 1800–1830,” Vol. II for 1822, p. 156.

=A.D. 1816.=--The Rev. James Bremmer, of the Shetland Islands, is rewarded by the Society of Arts for his night telegraph, the operation of which consists in the alternate exhibition and concealment of a torch in manner similar to that devised by Joachimus Fortius for Bishop Wilkins, as stated at A.D. 1641. This plan is said to have been successfully operated between the Copeland Island lighthouse and Port Patrick on the other side of the English Channel.

Particulars of the above-named night telegraph, as well as of the apparatus devised for day service, will be found in the Trans. of the Soc. of Arts, Vol. XXXIV. pp. 30, 213–227. The day telegraph consisted of a framework, having two circular openings, in each of which was a semicircular screen or shutter which, revolving upon an axis in the centre of the circle, was capable of assuming four different positions. This contrivance expressed an alphabet of sixteen letters, by dividing the latter into four classes of four each, and making one screen or shutter express the class, while the other indicated the number of the letter in that class.

=A.D. 1816.=--Sir Home Riggs Popham (1762–1820) British naval officer, who had been a rear-admiral in 1814, introduces his land semaphore which shows a great improvement upon all previous ones and at once replaces the Murray apparatus heretofore used by the English Admiralty (see A.D. 1795). It consists only of two arms placed upon the same hollow hexagonal mast, and movable upon separate pivots, each of which can be made to assume six different positions, giving together forty-eight different signals. It is fully described and illustrated at pp. 30, 167–177, Vol. XXXIV of the Trans. of the Soc. of Arts, and also appears in the “Telegraph” article, Vol. II of the “Encycl. of Useful Arts,” as well as at p. 149, Vol. XXIV of the “Penny Encycl.,” at pp. 67, 68, Vol. VIII of the (“Arts and Sciences”) “English Encycl.,” and in the “Telegraph” article by Sir John Barrow, one of the secretaries to the Admiralty, in the seventh “Britannica.”

In this same year (1816), Sir Home Popham also introduced a ship semaphore, which latter, as well as other similar devices of his construction, is to be found in the several publications already mentioned (the “Navy” article of the “Britannica” and pp. xii, xiii of Ronalds’ “Catalogue”).

=A.D. 1816.=--Ronalds (Francis), English experimentalist (1788–1873)--F.R.S., 1844, knighted 1870--whose serious attention to the development of electrical science appears to date from his meeting with M. De Luc in 1814, constructs at Hammersmith his telegraph which is the type of all dial instruments and which first presents the employment of two synchronous movements at the two stations. The telegraph is fully described and illustrated in the “Description of an Electrical Telegraph and of Some Other Electrical Apparatus,” 8vo, 83 pages, which Mr. Ronalds issued in pamphlet form, London, 1823, and which is said to be the first work published on electric telegraphy. Copious extracts from this are to be found at pp. viii-xi of the Ronalds “Catalogue,” and at pp. 129, 135–145, of Fahie’s “History,” the latter also containing several fine plates reproduced from the original work.

For his experimental line, Ronalds “erected two strong frames of wood at a distance of 20 yards from each other, and each containing 19 horizontal bars; to each bar he attached 37 hooks, and to the hooks were applied as many silken cords, which supported a small iron wire (by these means well insulated), which (making its inflections at the points of support) composed in one continuous length a distance of rather more than eight miles.” After making many experiments with this overhead line, he thus laid one underground:

“A trench was dug in the garden 525 feet in length, and four feet deep. In this was laid a trough of wood two inches square, well lined on the inside and out with pitch, and within this trough thick glass tubes were placed, through which the wire ran.”

His biographer, Mr. Frost, adds:

“In order to prevent the tubes from breaking by the variation of temperature, each length was laid a short distance from the next length, and the joint made with soft wax. The trough was then covered with pieces of wood, screwed upon it whilst the pitch was hot. They were also well covered with pitch, and the earth then thrown into the trench again.”

Mr. Edward Highton, at p. 40 of his work, the “Electric Telegraph,” 1852, says:

“Ronalds employed an ordinary electric machine and the pith-ball electrometer in the following manner. He placed two clocks at two stations; these two clocks had upon the second hand arbor a dial with twenty letters on it; a screen was placed in front of each of these dials, and an orifice was cut in each screen, so that only one letter at a time could be seen on the revolving dial. The clocks were made to go isochronously; and as the dials moved round the same letter always appeared through the orifices of each of these screens. The pith-ball electrometers were hung in front of the dials. The attention of the observer was called through the agency of an inflammable air gun fired by an electric spark.”

Realizing the value of his invention, Ronalds strove to bring it before the English Government, but was met (Aug. 5, 1816), with much the same encouragement we have seen vouchsafed Sharpe (A.D. 1813), and Wedgwood (A.D. 1814), viz. “Telegraphs of any kind are now wholly unnecessary and no other than the one now in use will be adopted.” The one alluded to was the semaphore line between London and Portsmouth, originally of the Chappe pattern and improved upon by Charles W. Pasley and Rear Admiral Popham.

Alluding to Mr. (afterward Sir) John Barrow’s letter in a note at p. 24 of his work Ronalds says:

“... Should they again become necessary, however, perhaps electricity and electricians may be indulged by his Lordship and Mr. Barrow with an opportunity of proving what they are capable of in this way.”

He was so disappointed that he not long after announced his “taking leave of a science which once afforded him a favourite source of amusement,” and that he was “compelled to bid a cordial adieu to electricity.” Fortunately for the scientific world, however, he afterward gave his attention again to electrical matters as is evidenced by many important papers contained in the publications noted below.

In Ronalds’ afore-named work the phenomenon of retardation of signals in buried wires is clearly foreseen and described, although Zetzsche endeavours to combat this assertion at p. 38 of his “Geschichte der Elektrischen Telegraphie,” Berlin, 1867. Speaking of the apprehended difficulty of keeping the wire charged with electricity, Ronalds suggests that when not at work “the machine be still kept in gentle motion to supply the loss of electricity by default of insulation; which default, perhaps, could not be avoided, because (be the atmosphere ever so dry, and the glass insulators ever so perfect), conductors are, I believe, robbed of their electricity by the same three processes by which Sir Humphry Davy and Mr. Leslie say that bodies are robbed of their sensible heat, viz. by radiation, by conduction, and by the motion of the particles of air.” He also gives descriptions of an improved electrical machine (eighth “Britannica,” Vol. VIII. p. 536; Sci. Am. Supp., No. 647, p. 10326; Noad’s “Manual,” p. 69), of a new method of electrical insulation and of some experiments on Vesuvius (Quarterly Jour. of Sci., Vols. II. p. 249; XIV. pp. 332–334), of a new electrograph for registering the charge of atmospheric electricity, of a pendulum doubler (Edin. Phil. Jour., Vol. IX, 1823, pp. 323–325) and of an attempt to apply M. De Luc’s electric column to the measurement of time. His other contributions relative to the dry pile are to be found in the Phil. Mag., Vols. XLIII. p. 414, and XLV. p. 466.

REFERENCES.--“Biog. Mem. of Sir Francis Ronalds, F.R.S.,” by Alfred J. Frost, in Ronalds’ “Catalogue”; “Mem. of Dist. Men of Science,” by William Walker; Ronalds’ “Corres. and Memoir.,” in 1848–1849, to 1853, to April 17, 1855, to June 5, 1856, to Sept. 2, 1862, and in 1866–1870; Ronalds’ “Walk Through ... Exh. of 1855”; Illustrated London News of April 30, 1870; eighth “Britannica,” Vol. VIII. pp. 622, 627, for Ronalds’ improved electrometers and his telegraph; Nature, London, Nov. 23, 1871, Vol. V. p. 59; Journal of the Telegraph, March 15, 1875, Vol. VIII. p. 82, reporting the inaugural address of Mr. Latimer Clark before the English Society of Tel. Engineers; Comptes Rendus for 1838, Vol. VII. pp. 593, etc.; _Sci. Am. Supp._, No. 384, pp. 6, 127; No. 547, p. 8735, and No. 659, p. 10521, for his Telegraph; “Bombay Mag. Observatory,” 1850; Fortschrift des Phys., Vol. III. p. 586, and Buys-Ballot “Meteor. Preisfrage,” 1847, for Ronalds’ apparatus to measure atmospheric electricity; Phil. Mag., Vols. XLIV. p. 442; XLV. p. 261; XLVI. p. 203; and third series, Vols. XXVIII for 1846; XXXI. p. 191; British Ass. Reports for 1845, 1846, and Reports concerning the Kew Observatory for 1845, 1850, 1852; Phil. Trans. for 1847, Moigno’s Le Cosmos, Vol. XIII; L. Von Forster, “All. Bauzeitung” for 1848, p. 238; Noad’s “Manual,” pp. 184, 185, 748; Knight’s “Mechanical Dictionary,” Vol. I. p. 708; Turnbull’s “Electro-magnetic Telegraph,” p. 22; _Annals of Electricity_, Vol. III. p. 449; “English Cyclop.” (Arts and Sci.), Vol. VIII. pp. 71, 72; Jour. Soc. Teleg. Eng., 1879, Part XV, xxxviii; Vol. VIII, first part, p. 361; Reply to Mr. W. F. Cooke’s pamphlet, “The Elec. Teleg.: Was it Invented by Prof. Wheatstone?” London, 1855; Du Moncel, Vol. III; “Telegraphic Tales,” 1880, p. 42; J. D. Reid, “The Telegraph in America,” 1887, p. 71; Ure’s “Dict. of Arts,” etc., London, 1878, Vol. II (Elect. Metal.), p. 230; T. P. Schaffner, “Tel. Man.,” 1859, pp. 147–156; Silliman, “Principles of Physics,” 1869, p. 617; “Edin. Phil. Journal,” 1823, Vol. IX. pp. 322, 395.

=A.D. 1816.=--Porret (Robert) (1783–1868) communicates to the Annals of Philosophy (Vol. VIII. p. 74) a paper “On Two Curious Galvanic Experiments” (Electrovection, Voltaic Endosmose, or Electro-chemical Filtration).

He observed that when water was placed in a diaphragm apparatus, one side of which was connected with the positive and the other side with the negative electrode of the battery, that a considerable portion of the liquid was transferred from the positive toward the negative side of the arrangement. It has since been found that the same result occurs in a minor degree when saline solutions are electrolyzed, and, generally, the greater the resistance which the liquid offers to electrolysis the greater is the amount which is thus mechanically carried over.... It appears from the researches of Wiedemann (Pogg., Ann., Vol. LXXXVII. p. 321), which have been confirmed by those of Quincke, that the amount of liquid transferred, cæteris paribus, is proportioned to the strength or intensity of the current; that it is independent of the thickness of the diaphragm by which the two portions of liquid are separated; and that when different solutions are employed, the amount transferred in each case, by currents of equal intensity, is directly proportional to the specific resistance of the liquid. Miller, from whom the above is taken, says that this transfer has been minutely studied by Quincke, and gives an account of the latter’s work extracted from the Ann. de Chimie, LXIII. p. 479. Brewster’s allusion to Porret and Wiedemann (eighth “Britannica,” Vol. VIII. p. 630) is followed by the statement that Mr. Graham considers ordinary endosmose as produced by the electricity of chemical action.

REFERENCES.--Graham, Vol. II. p. 266; De la Rive’s “Electricity,” Chap. IV. pp. 424–443; “Roy. Soc. Cat. of Sci. Papers,” Vol. IV. pp. 987, 988; Wm. Henry, “Elem. of Exp. Chem.” 1823, Vol. I. p. 178; C. Matteucci, “Traité des Phénom. Elect. Phys.,” 1844, p. 262 for Porret and Becquerel; Sturgeon’s “Sc. Researches,” Bury, 1850, p. 544; Poggendorff, Vol. II. p. 503; “Bibl. Britan.,” Vol. III, N.S., 1816, p. 15 (Thomson’s “Annals” for July 1816).

=A.D. 1817.=--Mr. J. Connolly makes known through an English and French pamphlet, entitled “An Essay on Universal Telegraphic Communication,” the details of his portable telegraph.

As shown in the thirty-sixth volume of the Transactions of the Society of Arts and in the twenty-fourth volume of the “Penny Cyclopædia,” his apparatus consists merely of three square boards painted with simple devices, like triangles, crescents, etc., the colours on the one side being the reverse of those on the other. Each of the six figures thus obtained is capable of producing four different distinct signals, making in all twenty-four, by successively turning each side of the board downward. In experiments made at Chatham, boards only eighteen inches square were found to answer for a distance of two miles, with a telescope having a magnifying power of twenty-five; and Mr. Connolly had also, it is said, exhibited these signals between Gros-nez and Sarque, a distance of seventeen miles, with boards twelve feet square.

At pp. 205, 208, of the Transactions of the Society of Arts, 1818, Vol. XXXV, and at p. 98, Vol. XXXVI for 1819, will be found Mr. Connolly’s system of telegraphing by means of flags in manner different from that of Lieut.-Col. John Macdonald alluded to at Pasley, A.D. 1808.

=A.D. 1817.=--In the “Encycl. Brit.” article treating of the influence of magnetism on chemical action, it is said that M. Muschman, Professor of Chemistry in the University of Christiania, made experiments to ascertain the effect of the earth’s magnetism on the precipitation of silver.

Desirous of explaining the chemical theory of the tree of Diana (Arbor Dianæ, first observed by Leméry), “he took a tube like a siphon and poured mercury into it, which accordingly occupied the lower part of the two branches; above the mercury he poured a strong solution of nitrate of silver. He then placed the two branches of the siphon so that the plane passing through them was in the magnetic meridian, and after standing a few seconds the silver began to precipitate itself with its natural lustre; but it accumulated particularly in the northern branch of the siphon, while that which was less copiously precipitated in the other branch had a less brilliant lustre, and was mixed with the mercurial salt deposited from the solution.” Muschman and Prof. Hansteen, having repeated this experiment with the same result, concluded that the magnetism of the earth had an influence on the precipitation of silver from a solution of its nitrate, and Muschman inferred from the experiment the identity of galvanism and magnetism (eighth “Britannica,” Vol. XIV. p. 42).

=A.D. 1817.=--Freycinet (Claude Louis Desaulses de) (1779–1842), captain in the French navy, is sent in command of an expedition fitted out by the French Government for the purpose of making scientific observations in a voyage round the world. The experimental stations were the Island of Rawak (near the coast of Guinea), Guam (one of the Ladrones), the Isle of France, Mowi (one of the Sandwich Islands), Rio Janeiro, Port Jackson, Cape of Good Hope, Paris and the Falkland Islands, as described in his “Voyage Autour du Monde ...” Paris, 1842.

His observations on the diurnal variations of the needle, which confirm the investigations made by Lieut.-Col. John Macdonald (A.D. 1808), are to be found at p. 54, Vol. XIV of the eighth “Britannica.”

REFERENCES.--His “Voyage de Découvertes ... 1800–1804 ...” (F. Péron and Louis Freycinet), also his “Navigation et Géog. ...” 1815; the note at p. 158, Vol. I of Humboldt’s “Cosmos,” London, 1849; Phil. Mag., Vol. LVII. p. 20.

=A.D. 1817.=--In Vol. XLII. pp. 165, 166, of the Transactions of the Society of Arts will be found a record of the explanation of his magnetic guard for needle pointers which Mr. Westcott made before the Committee of Mechanics during the year 1817. This is said to consist of several “bar magnets smeared over with oil placed in a frame behind the grindstone.”

=A.D. 1818.=--Bostock (John) (1774–1846), English physician, F.R.S., lecturer at Guy’s Hospital, publishes in London his “Account of the History and Present State of Galvanism,” which is scarcely more than a compilation of works treating of that branch of science.

One of the passages is, however, worth quoting, for it reflects the opinion shared by many physicists of the time that the resources of the galvanic field were already wellnigh exhausted. It thus appears at p. 102: “Although it may be somewhat hazardous to form predictions respecting the progress of science, I may remark that the impulse which was given in the first instance by Galvani’s original experiments, was revived by Volta’s discovery of the pile, and was carried to the highest pitch by Sir H. Davy’s application of it to chemical decomposition, seems to have, in a great measure, subsided. It may be conjectured that we have carried the power of the instrument to the utmost extent of which it admits; and it does not appear that we are at present in the way of making any important additions to our knowledge of its effects, or of obtaining any new light upon the theory of its action.”

Bostock is also the author of “Outline of the History of the Galvanic Apparatus”; “On the Theory of Galvanism” (Nicholson’s Journal for 1802); “On the Hypothesis of Galvanism” (Annals of Philosophy, III, 1814), and of other works upon different scientific subjects. Reference is made by Mr. William Leithead (“Electricity,” London, 1837, Chap. VI. pp. 296, 297) to Bostock’s “Elementary System of Physiology,” 1827, Vol. II. pp. 413, etc., wherein is shown among other results, that, contrary to the views of Dr. Philip, there is no necessary connection between “the nervous influence” and the action of the glands. At p. 306 of Leithead appears another extract, from the third volume of Bostock, relative to the application of the electro-physiological theory in elucidating the phenomena of disease.

REFERENCES.--Poggendorff, Vol. I. pp. 249, 250; “Nicholson’s Journal,” Vols. II. p. 296, and III. p. 3; Figuier, “Expos. et Histoire,” 1857, Vol. IV. p. 425; Gilbert, Vol. XII. p. 476.

=A.D. 1819.=--Hansteen (Christoph) (1784–1873), Norwegian astronomer and physicist, embodies in his notable work, “Untersuchungen über den Magnetismus der Erde ...” (“Inquiries regarding the magnetism of the earth”), the result of his extensive researches concerning terrestrial magnetism, the account of which is accompanied by a chart indicating the magnetic direction and dip at numerous places. This work, which is said to have been practically completed in 1813 (Humboldt, “Cosmos,” 1859, Vol. V. p. 66), was translated by the celebrated Peter Andreas Hansen (Poggendorff, Vol. I. pp. 1013–1015) from the original manuscript and published in German. It attracted much attention throughout the scientific world, and so highly was it thought of that in almost all the voyages of discovery afterwards undertaken most magnetic observations were made according to its directions.

Through the “Encyclopædia Britannica” we learn that Hansteen’s able work was first made known in England by Sir David Brewster through two articles in the Edin. Phil. Journal for 1820, Vol. III. p. 138, and Vol. IV. p. 114, and that an account of his subsequent researches, drawn up by Hansteen himself, appeared in the Edin. Journal of Science for 1826, Vol. V. p. 65. It is also stated that the Royal Society of Denmark proposed in 1811 the prize question, “Is the supposition of one magnetical axis sufficient to account for the magnetical phenomena of the earth, or are two necessary?” Prof. Hansteen’s attention had been previously drawn to this subject by seeing a terrestrial globe, on which was drawn an elliptical line round the south pole and marked Regio polaris magnetica, one of the foci being called Regio fortior, and the other Regio debilior. As this figure professed to be drawn by Wilcke, from the observations of Cooke and Furneaux, Hansteen was led to compare it with the facts; and the result of his researches was favourable to that part of Halley’s theory which assumes the existence of four poles and two magnetic axes. Hansteen’s Memoir, which was crowned by the Danish Society, forms the groundwork of his larger volume published in 1819. “In his fifth chapter, on the Mathematical Theory of the Magnet, he deduces the law of magnetic action from a series of experiments similar to those of Hauksbee and Lambert.... In determining the intensity of terrestrial magnetism Professor Hansteen observed that the time of vibration of a horizontal needle varied during the day. Graham had previously suspected a change of this kind, but his methods were not accurate enough to prove it. Hansteen found that the minimum intensity took place between ten and eleven a.m., and the maximum between four and five p.m. He concluded also that there was an annual variation, the intensity being considerably greater in winter near the perihelion, and in summer near the aphelion; that the greatest monthly variation was a maximum when the earth is in its perihelion or aphelion, and a minimum near the equinoxes; and that the greatest daily variation is least in winter and greatest in summer. He found also that the aurora borealis weakened the magnetic force, and that the magnetic intensity is always weakest when the moon crosses the equator.”

According to Dr. Whewell (“History of Induc. Sciences,” 1859, Vol. II. p. 226), the conclusions reached by Hansteen respecting the position of the four magnetic “poles” excited so much interest in his own country that the Norwegian Storthing, or Parliament, by a unanimous vote provided funds for a magnetic expedition which he was to conduct along the north of Europe and Asia, and this they did at the very time when, strange to say, they refused to make a grant to the King for building a palace at Christiania. The expedition was made in 1828–1830, and verified Hansteen’s anticipations as to the existence of a region of magnetic convergence in Siberia, which he considered as indicating a “pole” to the north of that country. The results were published in Hansteen and Due’s “Resultate magnetischer ...” (“Magn., Astron. and Méteor. Obs. on Journey through Siberia”) which appeared in 1863.

In the Sixth Dissertation, Chap. VII of the “Encycl. Brit.,” it is said that, next to Prof. Hansteen, science is mainly indebted for the great extension of our knowledge of the facts and the laws of terrestrial magnetism to two illustrious German philosophers, Baron Alexander von Humboldt and Prof. Karl Friedrich Gauss (1777–1855). An account is therein given of Gauss’s individual investigations, as well as of the researches he made in conjunction with Wilhelm Eduard Weber (1804–1891), who was likewise a professor at Göttingen. Of Alex. von Humboldt, we have spoken fully under date 1799, and of Gauss and Weber, mention has already been made at Schilling (A.D. 1812).

The very valuable contributions of Gauss and Weber appear throughout all the many scientific publications of the period, notably in the “Abhandlung d. Gött. Geselsch. d. Wiss.,” their joint work being shown to advantage in the important “Resultate ... des Magnet. Vereins,” published in Leipzig, 1837–1843.[58]

REFERENCES.--For M. Hansteen’s scientific papers and for an account of additional magnetic results obtained by himself and others, consult the eighth “Britannica,” Vols. I. p. 745; IV. p. 249; XIV. pp. 15, 23, 42 (experiment with M. Muschman), 50, 55, 57–64, et seq., for Morlet and others; Thomson’s “Outline of the Sciences,” London, 1830, pp. 546–548; Whewell, “History of the Induc. Sci.,” Vol. II. pp. 613, 615, also p. 219 for Yates and Hansteen; Johnson’s new “Univer. Encycl.,” 1878, Vol. III. pp. 231–234 for Morlet, etc.: Weld’s “Hist. of Roy. Soc.,” Vol. II. p. 435; “Edin. Jour. of Sci.,” London, 1826, Vols. I. pp. 87, 334; V. pp. 65–71, 218–222; “Report of Seventh Meeting British Association,” London, 1838, Vol. VI. pp. 76, 82; J. G. Steinhauser’s articles published between 1803 and 1821; Harris’ “Rudimentary Magnetism,” London, 1852, Part. III. pp. 38, 39, 111; Phil. Mag., Vol. LIX. p. 248, and Phil. Mag. or Annals, Vol. II. p. 334; “Zeitschr. f. pop. Mitth.,” I. p. 33; Schweigger’s Journal, 1813–1827; Poggendorff’s Annalen, 1825–1855; “Académie Royale de Belgique” for 1853, 1855, 1865; C. Hansteen and C. Fearnley, “Die Univ.-Sternwarte ...” 1849; Hansteen, Lundh and Muschman, “Nyt. Mag. for Naturvid,” 1823–1856. See likewise his biography in the “English Cyclop. Supplement,” pp. 642, 643; “Catal. Roy. Soc. Sc. Pap.,” Vol. III. pp. 167–172; Vol. VI. p. 681, Vol. VII. p. 905; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 157; “Edin. Phil. Journal,” 1823, Vol. IX. p. 243; “Annual Rec. Sc. Disc.,” 1873, p. 683; 1875, p. 155; Knight’s “Amer. Mech. Dict.,” 1875, Vol. II. p. 1374, and eighth “Britan.,” Vol. XIV. p. 49, regarding Hansteen’s lines of no variation for 1787; Humboldt’s “Cosmos,” 1859, Vol. V. pp. 110–111, for the investigations of Hansteen, Sir Ed. Belcher and others, those of the last named being treated of at p. 493 of the Phil. Trans. for 1832; Noad, “Manual,” pp. 529, 530, 534, 616, 617, etc.; Appleton’s “New Am. Cycl.,” Vol. XI. p. 64.

=A.D. 1819.=--Hare (Robert) (1781–1858) who was for twenty-nine years Professor of Chemistry in the Pennsylvania University, publishes in Philadelphia “A New Theory of Galvanism, Supported by Some Experiments and Observations Made by Means of the Calorimotor ...” of which an English edition appears in London the same year. (A full review of this work is to be found more particularly at p. 206, Vol. LIV of the Philosophical Magazine; in the “Encycl. Metropol.,” Vol. IV (Galvanism), p. 222; in Ure’s “Dictionary of Chemistry,” Am. ed., article “Calorimotor”; at p. 187 of the Phil. Trans. for 1823; at pp. 409, 410, Vol. I of Gmelin’s “Chemistry,” and at pp. 413–423, Vol. I of Silliman’s Am. Jour. of Sci., the last named being accompanied by a very fine illustration of the Calorimotor.)

This apparatus, which has already been alluded to (Pepys, A.D. 1802), consists of sheets of zinc about 9 inches by 6, and of copper about 14 inches by 6, coiled around one another nearly half an inch apart; there being in all 80 coils, 2½ inches in diameter, which are let down by means of a lever into glass vessels containing the acid solution. Dr. Hare observes:

“Volta considered all galvanic apparatus as consisting of one or more electromotors, or movers of the electric fluid. To me it appeared that they were movers of both heat and electricity; the ratio of the quantity of the latter put in motion to the quantity of the former put in motion being as the number of the series to the superficies. Hence the word electromotor can only be applicable when the caloric becomes evanescent, and electricity almost the sole product, as in De Luc’s and Zamboni’s columns; and the word calorimotor ought to be used when electricity becomes evanescent and caloric appears the sole product.”

“It afterwards appeared quite natural,” remarks Mr. W. B. Taylor (Note B, “Mem. of Jos. Henry,” p. 376) “to distinguish these classes of effects by the old terms--‘intensity’ for electromotive force, and ‘quantity’ for calorimotive force. There is obviously a close analogy between these differences of condition and resultant, and the more strongly contrasted conditions of mechanical and chemical electricity; and indeed the whole may be said to lie in a continuous series, from the highest ‘intensity’ with minimum quantity, to the greatest ‘quantity’ with minimum intensity.”

Two years later (1821), Dr. Hare constructed his galvanic deflagrator. It consists of two pairs of troughs, each ten feet long, and containing 150 galvanic pairs, so arranged that the plates can all be simultaneously immersed into or withdrawn from the acid. Each pair turns on pivots made of iron, coated with brass or copper, and a communication is established between these and the voltaic series within by means of small strips of copper. The “Encycl. Brit.” gives a full description of the construction and working of the apparatus, as do also the “Encycl. Metropol.,” Vol. IV (Galv.), p. 176; Noad (“Manual,” pp. 266, 267); Gmelin (“Chemistry,” Vol. I. pp. 409, 410), and Silliman (“Journal of Sci. and Arts,” Vol. VII. p. 347). The first-named publication says of Dr. Hare’s deflagrator:

“A brilliant light, equal to that of the sun, was produced between charcoal points, and plumbago and charcoal were fused by Profs. Silliman and Griscom. By a series of 250, baryta was deflagrated, and a platina wire, three-sixteenths of an inch in thickness, ‘was made to flow like water.’ In the experiments with charcoal, the charcoal on the copper side had no appearance of fusion, but a crater-shaped cavity was formed within it, indicating that the charcoal was volatilized at this side and transferred to the other, where it was condensed and fused, the piece of charcoal at this pile being elongated considerably. This fused charcoal was four times denser than before fusion. In a letter from Prof. Silliman, which was transcribed in the Sc. Am. Sup. for Sept. 21, 1878, he says: ‘Undoubtedly the earliest exhibitions of electric light from the voltaic battery were those made with the deflagrators of Dr. Hare by Prof. Silliman at New Haven in 1822, and subsequently on a magnificent scale at Boston in 1834, when an arc of over five inches diameter was produced by the simultaneous immersion of 900 large-sized couples of Hare’s deflagrator. But no means had then been devised for the regulation of the electric light to render it constant, and although the writer as early as 1842 used this light successfully to produce daguerreotypes, the progress of invention had yet to make further use of the discovery of science before electrical illumination was possible.’”

The description of Dr. Hare’s electrical machine (before alluded to at Van Marum A.D. 1785), wherein the plate is mounted horizontally so as to show both negative and positive electricity, was published in London during 1823, and can be found in Vol. LXII of the Phil. Mag., as well as at pp. 538, 604, 605, Vol. VIII of the 1855 “Encycl. Brit.” In the last-named article mention is made of the introduction of a band (illustrated Fig. 7, Plate CCXXII) which prevents the plate from being cracked, as it frequently is, through some hasty effort to put it in motion while it adheres to the cushions. It is also therein stated that in order to offset the heavy expense attending the breakage of large cylinders and plates, M. Walkiers de St. Amand, of Brussels, among many others, made an apparatus of varnished silk 25 feet long and 5 feet wide, capable of giving sparks 15 inches long (see A.D. 1785), while Dr. Ingen-housz constructed machines with pasteboard discs four feet in diameter, soaked in copal or amber varnish dissolved in linseed oil, which gave sparks of one and even two feet in length.

In the fifth volume, new series, of the Amer. Phil. Trans. will be found Dr. Hare’s “Description of an Electrical Machine,” with a plate four feet in diameter, so constructed as to be above the operator; also of a battery discharger employed therewith, and some observations on the causes of the diversity in the length of the sparks erroneously distinguished by the terms positive and negative. Hare is also the inventor of a single gold-leaf electroscope of such great delicacy that it has, he says, enabled him to detect the electricity produced by one contact between a zinc and copper disc, each six inches in diameter (Noad, “Manual,” p. 29; Harris’ “Rudim. Elect.,” p. 50; Silliman’s Journal, Vol. XXXV). He invented several other electrical appliances, and he is likewise the author of numerous important memoirs which it would be impossible to detail in the narrow limits of this “Bibliographical History.” They will, however, be found recorded in the publications named below.

REFERENCES.--Phil. Trans. for 1769, Vol. LXIX. p. 659. See also, for Walkiers de St. Amand, the entry at A.D. 1785, as well as Lichtenberg’s Magazin, Vol. III, 1st, p. 118, for the last-named year. To these might be added the machines made by Mundt, of silken strips (Gren’s Journal der Physik., Vol. VII. p. 319); by N. Rouland, “Descript. des mach, elec. à taffetas,” Amsterdam, 1785; by Croissant and Thore; of paper by W. H. Barlow (Phil. Mag., Vol. XXXVII. p. 428), of gutta percha; as well as machines of rubber by Fabre and Kunneman, as shown at Th. Du Moncel’s “Exposé des appl. de l’El.,” second ed., p. 399, and third ed., 1872, Vol. II. pp. 78, 122, 265, besides the peculiarly constructed machines of Erdmann Wolfram (Ferussac, “Bulletin des Sciences Tech.” for 1824); of G. H. Seiferheld, “Beschreib ... elektrische mach,” 1787; of F. E. Neuman, as modified by F. Zantedeschi (“Ann. Sci. Lom.-Ven.,” XII. p. 73), and of those described at p. 420, Vol. II, and at p. 4, Vol. III of Nicholson’s Magazine. Consult likewise, pp. 335, 340, second Am. ed. of the “New Edin. Encycl.,” 1817. Poggendorff, Vol. I. pp. 1018, 1019; “Cat. Sci. Papers of Roy. Soc.,” Vol. III. pp. 177–182; Vol. VI. p. 182; Silliman’s Am. Jour. Sci. and Arts, Vols. II. pp. 312, 326; III. p. 105; IV. p. 201; V. p. 94; VII. pp. 103, 108, 351; VIII. pp. 99, 145; X. p. 67; XII. p. 36; XIII. p. 322; XV. p. 271; XXIV. p. 253, XXV. p. 136; XXXI. p. 275; XXXII. pp. 272, 275–278, 280–285; XXXIII. p. 241; XXXV. p. 329; XXXVII. pp. 269, 383; XXXVIII. pp. 1, 336, 339; XXXIX. p. 108; XL. pp. 48, 303; XLI. p. 1, and XLIII. p. 291; Phil. Mag., Vols. LVII. p. 284; LXII. pp. 3, 8, etc.; Phil. Mag. or Annals, Vol. VI. pp. 114, 171; Journal of the Franklin Institute, third series. Vol. XV. pp. 188, etc.; Trans. of the Am. Phil. Soc., N.S., Vol. VI. p. 297 (for Hare and Allen) also pp. 339, 341, 343, and Vol. VII for 1841; “Mem. Jos. Henry,” Washington, 1880, p. 82; Figuier, “Exp. et Hist.,” 1857, Vol. IV. pp. 391, 401, 402; Dr. Thomas Thomson, “Outline of the Sc.,” London, 1830, pp. 515, 517; Appleton’s “New Amer. Cycl.,” Vol. VII. p. 66; Appleton’s “Dict. of Machines, Mechanics ...” 1861, pp. 432, 433; Dr. William Henry, “Elem. of Exper. Chem.,” London, 1823, Vol. I. p. 169, and Supplement, Chap. VII. p. 29; “Annual of Sc. Disc.” for 1862, p. 99.

=A.D. 1819.=--Gmelin (Leopold), the most distinguished member of the family of that name, publishes, at Frankfort, 1817–1819, the first edition of his celebrated “Handbuch d. theoret. Chemie,” which embodies the whole extent of chemical science as it then existed and the fourth and last edition of which, under the author’s supervision, appeared during 1843–1845. This extensive work is well known, both in its original form and through the very able translation of it made by Mr. Henry Watts. In the report of the Council of the Chemical Society for 1854, it is said that “the greatest service which Gmelin rendered to science--a service in which he surpassed all his predecessors and all his contemporaries--consists in this: that he collected and arranged in order all the facts that have been discovered in connection with chemistry. His Handbuch der theoret Chemie stands alone. Other writers on chemistry have indeed arranged large quantities of materials in systematic order, but for completeness and fidelity of collation and consecutiveness of arrangement, Gmelin’s Handbuch is unrivalled.”

Although many references have been made herein to Leopold Gmelin’s treatment of such departments of science as directly appeal to the readers of this compilation, it is well to mention some of the headings under which they are to be found. They are, “Electricity,” “Electro-chemical Theories,” “Electrolysis,” “Technical Apparatus of Electricity,” “Theory of Galvanism,” “Galvanic Batteries,” “Magnetic Condition of All Matter,” etc., etc., the whole occupying pp. 304 to 519, Vol. I of Gmelin’s English edition. The list of many of Leopold Gmelin’s valuable contributions to science is given in the “Catalogue Sc. Papers Roy. Soc.,” besides which may be mentioned his “Uber e angebl. meteorische masse” (Gilbert, Annalen, LXXIII for 1823), and his “Versuch einer elektro-chemisch. theorie” (Poggendorff’s Annalen der Physik und Chemie, Vol. XLIV for 1838, while at pp. 547–550 of Mr. J. J. Griffin’s able work, published in London during 1858, will be found the results obtained by Prof. G. Magnus and by Prof. Faraday with a summary of Gmelin’s conclusions under the heading of “The Evidence of Electrolysis in Favour of the Radical Theory.”

GMELIN FAMILY

This family, which, through four generations, has been continuously distinguished for its valuable contributions to chemistry as well as to the natural and medical sciences, deserves equally well here of such a special mention as was accorded to the Bernoulli and Cassini families, under dates A.D. 1700 and 1782–1791.

Johann Georg Gmelin (1674–1728), a very able chemist and pharmaceutist of Tübingen, was the father of:

Johann Conrad Gmelin (1707–1759), physician and author in the same city of Tübingen.

Johann Georg Gmelin (1709–1755), distinguished naturalist and chemist, who graduated as M.D. in his nineteenth year, became a member of the St. Petersburg Acad. of Sc. and was sent by the Empress Anna, in company with G. A. Müller and other noted scientists, upon a ten years’ exploring expedition through Siberia. He was one of the first explorers of Northern Asia, and a genus of Asiatic plants was named Gmelina after him by Linnæus.

Philip Friedrich Gmelin (1722–1768), Professor of Botany and of Chemistry at Tübingen, author of many scientific monographs.

Samuel Gottlieb Gmelin (1744–1774), elder son of Philip Friedrich, who, like his uncle, graduated M.D. at nineteen and was sent two years later by the Empress Catherine II upon a scientific tour through South-Eastern Russia, is the author of “Historia Fucorum ...” as well as of other contributions which were edited through the famous Pallas. His biographical notice appears in the last volume of the “Reise durch Russland ...” published at St. Petersburg.

Johann Friedrich Gmelin (1748–1804), M.D., succeeded his father, Philip Friedrich, in the chair of chemistry and botany at the Tübingen University, became Professor of Medicine at Göttingen in 1778 and a member of “l’Académie des Curieux de la Nature.” He is the author of the thirteenth edition of Linnæus’ “Systema Naturæ,” which, notwithstanding Cuvier’s severe criticism of it, is said to be the only work which even professes to embrace all the objects of natural history described up to the year 1790 (“Encycl. Brit.,” 1855, Vol. IX. p. 4). He is also the author of “Geschichte der Chemie ...” Göttingen, 1797–1799, and of “Prælectio de col. metal. a Volta ...” (“Commentat. Soc. Gött.” XV (Phys.) for 1800–1803, p. 38). (See J. C. Poggendorff, “Biogr.-Literar. Handwörterbuch,” Vol. I. pp. 914–915.)

His son, Leopold Gmelin (1788–1853), who has already been noticed, practised chemical manipulation in the Tübingen pharmaceutical laboratory of Dr. Christian Gmelin, the son of Johann Conrad, and studied at Göttingen, Vienna and in Italy, after which he became medical and chemical professor at Heidelberg, 1817–1851 (Poggendorff, Vol. I. pp. 915–916).

Ferdinand Gottlob von Gmelin (1782–1848), elder son of Dr. Christian Gmelin, was Professor of Medicine and of Natural History in the Tübingen University, and wrote “Diss. sistens obs. phys. et chem. de electricitate et galvanismo” during 1802 (Poggendorff, Vol. I. pp. 916–917).

Christian Gottlob Gmelin (1792–1860), brother of the last named, M.D., was Professor of Chemistry and Pharmacy at the Tübingen University, and the author of “Experimenta electricitatem ...” 1820; “Uber d. Coagulat. ... d. Electricität” (Schweigger’s “Journal,” Vols. XXXVI for 1822); “Analyse d. turmalins ...” (Schweigger’s “Journal,” Vols. XXXI for 1821 and XXXVIII for 1823--Poggendorff’s “Annalen,” Vol. IX for 1827), as well as of a “Handbuch der Chemie,” published 1858–1861 (Poggendorff, Vol. I. p. 917; Phil. Mag. or Annals, Vol. III. p. 460).

REFERENCES.--Gmelin and Schaub, “Effets Chimiques de la col. metal ...” (“Magas. Encyclop.,” Vol. VI. p. 201); Eberhard Gmelin’s letter to M. Privy Councillor Hoffmann of Mayence (1787), and his new investigations (1789) on the subject of animal magnetism (“Salzb. Med. Chir. Zeit.,” 1790, I. p. 358); Whewell, “Hist. of the Ind. Sc.,” 1859, Vol. II. p. 348.

=A.D. 1819.=--Dana (J. F.), M.D. (1793–1827), Chemical Assistant in Harvard University and Lecturer on Chemistry and Pharmacy in Dartmouth College, writes, Jan. 25, 1819, to Prof. Benjamin Silliman concerning his new form of portable electrical battery.

This apparatus, consisting of alternate plates of flat glass and of tinfoil, the sheets of which latter are connected together, is fully described at pp. 292–294, and is illustrated opposite p. 288, Vol. I of Silliman’s American Journal of Science, 1818, wherein it is stated that, while “in a battery of the common form, 2 feet long, 1 foot wide and 10 inches high, containing 18 coated jars, there will be no more than 3500 square inches of coated surface,” a battery of Dana’s construction will have no less than 8000 square inches covered with tinfoil, allowing the sheet of glass and of foil to be a quarter of an inch thick. In a brief description of this apparatus, which appears at p. 468, Vol. V of Tilloch’s Phil. Mag. and Journal, it is stated that a “battery constructed in this way contains, in the bulk of a quarto volume, a very powerful instrument; and when made of glass it is extremely easy, by varnishing the edges, to keep the whole of the inner surfaces from the air, and to retain it in a constant state of dry insulation.”

=A.D. 1820.=--Oersted--Örsted (Hans Christian), native of Denmark (1770–1851), Professor of Natural Philosophy and founder of the Polytechnic School in Copenhagen, makes known, through a small four-page pamphlet entitled “Experimenta circa effectum conflictus electrici in acum magneticam,” his great discovery of the intimate relation existing between electricity and magnetism (Thomson’s Annals of Philosophy for October 1820, Vol. XVI, first series, pp. 273–276). He thus lays the foundation of the science of electro-magnetism, which subsequently was so materially developed by Ampère and Faraday.

It is said that after taking his doctor’s degree in 1799, he gave much attention to galvanism, and that in the year 1800 he made important discoveries as to the action of acids during the production of galvanic electricity. He was one of the earliest to show the opposite conditions of the poles of the galvanic battery, also that acids and alkalies are produced in proportion as they neutralize each other. Upon his return from a trip to France and Germany, 1801–3, he lectured on electricity and the cognate sciences, publishing thereon a number of essays. (These are to be found, more particularly, in J. H. Voigt’s Magazin, Vol. III. p. 412; Van Mons’ Journal, No. IV. p. 68; the Bulletin of the Société Philomathique, No. LXVII. an. xi. p. 128; A. F. Gehlen’s Neues Allgem. Journal d. Chemie, Vols. III for 1804, VI for 1806, VIII for 1808; Schweigger’s Journal, Vol. XX; Phil. Mag., Vol. XXIII. p. 129; the “Skand. Lit.-Selskabs Skrifter,” Vol. I; “Oversigt over det Kongl. ... Forhandlinger,” 1814–1815; “Nyt Biblioth. f. Physik,” etc., Vol. IX, and in the Journal de Physique as well as in the Journal du Galvanisme.)

He revisited Germany during 1812, and, at the suggestion of Karsten Niebuhr, published in Berlin his work “Ansicht der Chemischen Naturgesetze. ...” (“Inquiry into the identity of chemical and electric forces”), a translation of which was made by M. P. Marcel T. de Serres under the title of “Recherches sur l’Identité. ...” (Fahie, “Hist. of Electric Teleg.,” 1884, pp. 270–273). The last-named work appeared at Paris during 1813, and not, as stated at p. 41, Vol. LVII of the Philosophical Magazine, during 1807, which was the date of the original small German edition.[59]

One of his biographers says that Oersted was lecturing one day to a class of advanced students, when, as a means of testing the soundness of the theory which he had long been meditating, it occurred to him to place a magnetic needle under the influence of a wire uniting the ends of a voltaic battery in a state of activity. “In galvanism,” said he, “the force is more latent than in electricity, and, still more so in magnetism than in galvanism; it is necessary therefore to try whether electricity, in its latent state, will not affect the magnetic needle.” He tried the experiment upon the spot and found that the needle tended to turn at right angles to the wire, thus proving the existence of electro-magnetism, or the relation of electricity and magnetism as mutually productive of each other, and as evidences of a common source of power. Previous to this time the identity of magnetism and electricity had only been suspected. For several months Oersted prosecuted experiments on the subject, and on the 21st of July 1820 promulgated his discovery through the Latin pamphlet above alluded to. Therein he contends that there is always a magnetic circulation around the electric conductor, and that the electric current in accordance with a certain law always exercises determined and similar impressions on the direction of the magnetic needle, even when it does not pass through the needle but near it (the eighth edition of the “Encycl. Britannica,” Fifth Dissertation, pp. 739, 740, 745; and the Sixth Dissertation, pp. 973–976; Schaffner, “Tel. Manual,” 1859, Chap. VIII; Practical Mechanic, Glasgow, 1842, Vol. III. p. 45).

For this discovery, which naturally excited the wonder of the entire scientific world, he received the Copley medal of the English Royal Society, the Dannebrog order of knighthood and numerous testimonials from nearly every quarter of Europe. As observed by Mr. J. D. Forbes (Sixth Disser. “Encycl. Brit.,” Vol. I), “the desideratum of a clear expression of the manifest alliance between electricity and magnetism has been so long and so universally felt that the discovery placed its author in the first rank of scientific men.... The prize of the French Institute, which had been awarded to Davy for his galvanic discoveries, was bestowed upon Oersted.”

Oersted’s experiments were repeated before the French Academy of Sciences by M. De la Rive on Sept. 11, 1820, and, seven days later, as we shall see, Ampère made known the law governing electro-magnetism (Mme. Le Breton, “Hist. et. Appl. de l’Elect.,” Paris, 1884, pp. 72, 73; W. Sturgeon, “Sci. Researches,” Bury, 1850, p. 18; Higg’s Translation of Fontaine’s “Electric Lighting,” London, 1878, p. 54).

The many investigations subsequently carried on by Oersted in different branches of sciences are alluded to in the works named below. Perhaps the most interesting, outside of the ones already spoken of, are those attaching to thermo-electricity which he made in conjunction with Baron Fourier, and independently of Dr. Seebeck.

REFERENCES.--Eighth “Britannica,” pp. 651 and 652, Vol. XXI, as well as pp. 11 and 12, Vol. XIV of Oersted’s “Efterretning om nogle nye, af Fourier og Oersted ...” Kiobenhaven, 1822–1823, translated into French as mentioned in Vol. XXII of the Annales de Chimie et de Physique; “Oversigt over det Kongl. ...” for 1822–1823 and 1823–1824; Poggendorff, Vol. III. pp. 309–312; “Catal. Sci. Papers Roy. Soc.,” Vol. I. pp. 697–701; Biog. Sketch by P. L. Möller, “Oersted’s Character und Leben,” 1851, also Hauch und Forchammer, 1853; Obituary notice in Jour. Frankl. Inst., 1851, Vol. XXI. p. 358; Humboldt, “Cosmos,” 1849, Vol. I. pp. 182, 185 and the 1819–1820 entry of “Magnetic Observations,” in Vol. V; “Oversigt over det Kongl. danske Videnskabernes Selskabs Fordhandlinger” for 1822, 1832, 1834–1835, 1836–1837, 1840–1842, 1847–1849; Poggendorff’s Annalen, Vol. LIII; “Ursin’s Magaz. f. Kunstnere ...” Vols. I and II; “Dict. of Electromagn.,” 1819; Sturgeon’s Annals of Electricity, Vol. I. p. 121; Hatchett “On the Experim. ... of Oersted and Ampère” (Phil. Mag., Vol. LVII. p. 40), Phil. Mag., Vols. LVI. p. 394; LVII. pp. 47–49; LIX. p. 462; Phil. Mag. or Annals, Vol. VIII. p. 230; Annales de Chimie for Aug. 1820, p. 244; S. S. Eyck, “Over de magnetische ...” (Bibl. Univ., 1821); Translation by H. Sebald, of H. C. Oersted’s “Leben,” 1853; Michaud, “Biog. Univ.,” Vol. XXXI. p. 196; P. L. Möller, “Der Geist in der Natur” (”The Spirit in Nature”); Elie de Beaumont, “Memoir of Oersted” (“Smith. Rep.” for 1863); Gilbert’s Annalen, Vol. LXVI. p. 295, 1820; Callisen, “Medicinisches Schriftseller-Lexikon”; W. Sturgeon’s “Sci. Researches,” Bury, 1850, p. 8 (for 1807), and pp. 9–12 for English version of Oersted’s pamphlet which was translated in German in Vol. XXIX of Schweigger’s “Journal,” as well as in Vol. LXVI of Gilbert’s Annalen, and which appeared in French in Vol. XIV of the Annales de Chimie et de Physique for 1820, as well as in Vol. II. pp. 1–6 of “Collection de Mémoires relatifs à la Physique,” Paris, 1885. See also “Biogr. Gén.,” Vol. XXXVIII. pp. 522–535; “Göttinger Gelehrte Anz.,” No. 171; Sturgeon’s “Sc. Researches,” pp. 17, 18, 28, 415; Thomson’s “Annals of Philosophy,” Vol. XVI. p. 375 for second series of observations; Van Marum on “Franklin’s Theory of Electricity,” pp. 440–453; “Galvanism,” by Mr. John Murray, p. 467; “Note sur les expériences ... de Oersted, Ampère, Arago, et Biot,” (Annales des Mines, 1820); L. Turnbull, “Elec. Mag. Tel.,” 1853, pp. 45, 221; J. F. W. Herschel’s “Preliminary Discourse,” 1855, pp. 244, 255; Fahie, “Hist. Elec. Tel.,” 1884, pp. 270–275, Harris, “Rud. Elec.,” 1853, p. 171; Ostwald’s Klassiker, No. 63 and “Elektrochemie,” 1896, p. 67; Mrs. Somerville, “Con. of Phys. Sci.,” 1846, p. 314; Noad, “Manual,” p. 642; “Lib. Useful Know.” (El Magn.), pp. 4, 79; Lardner’s “Lectures,” 1859, Vol. II. p. 119; Tomlinson’s “Cycl. Useful Arts,” Vol. I. p. 559; Ure’s “Dict. of Arts,” 1878, Vol. II. p. 233; Henry Martin’s article in Johnson’s “New Cyclopædia,” 1877, Vol. I. pp. 1512, 1514; “Nyt Biblioth. f. Physik,” Band I auch Scherer’s Nord. Arch., II; “Tidskrift f. Natur ...” I 1822: Schumacher’s “Astron. Jahrbuch” for 1838; L. Magrini, “Nuovo metodo ...” Padova, 1836; Boisgeraud “On the Action of the Voltaic Pile ...” (Phil. Mag., Vol. LVII. p. 203); Sci. Am. Suppl., No. 454, p. 7241; Schweigger’s Journal, Vols. XXXII, XXXIII, LII; Figuier, “Expos. et Hist.,” 1857, Vol. IV. p. 393; “Engl. Cycl.,” “Arts and Sci.,” Vol. III. p. 782; Brande’s “Man. of Chem.,” London, 1848, Vol. I. p. 248; Prime’s “Life of Morse,” pp. 264, 451; Dr. Henry’s “Elm. of Exper. Chem.,” London, 1823, Vol. I. pp. 193–203; Jour. of the Frankl. Inst. for 1851, Vol. XXI. p. 403; “La Lumière Electrique” for Mar. 19, 1887, p. 593, and for Oct. 31, 1891, pp. 201, etc.: Sir William Thomson, “Math. Papers,” reprint, etc., 1872; “Encyl. Metrop.” (Elect. Mag.,); G. B. Prescott, “Elect. and the El. Tel.,” 1885, Vol. I. p. 91; “Smithsonian Report” for 1878, pp. 272, 273, note; Bacelli (L. G.), “Risultati ...” Milano, 1821; “Bibl. Britan.,” Vol. XVII, N.S. p. 181; Vol. XVIII, N.S. p. 3; “Edin. Phil. Journal,” Vol. X. p. 203; “Journal of the Soc. of Tel. Eng.,” 1876, Vol. V. pp. 459–464, for a verbatim copy of Oersted’s original communication on his discovery of electro-magnetism, and pp. 464–469 for a translation thereof by the Rev. J. E. Kempe under the title of “Experiments on the effect of electrical action on the Magnetic Needle.” For the interesting electro-magnetic experiments of J. Tatum, at this same period, consult the Phil. Mag., Vol. LVII, 1821, p. 446; Vol. LXI, 1823, p. 241; Vol. LXII, 1823, p. 107, and, for additional investigation, the Vols. XLVII and LI for years 1816 and 1818.

=A.D. 1820.=--On Oct. 9, M. Boisgeraud, Jr., reads, before the French Académie des Sciences, a paper concerning many of his experiments, which prove to be merely variations of those previously made by Oersted.

He observed that connecting wires, or arcs, placed anywhere in the battery, affect the needle, and he noticed the difference of intensity in the effects produced when electrical conductors are employed to complete the circuit. He proposed to ascertain the conducting power of different substances by placing them in one of the arcs, cells or divisions of the battery, and bringing the magnetic needle, or Ampère’s galvanometer, toward another arc, viz. to the wire or other connecting body used to complete the circuit in the battery. With regard to the positions of the needle and wire, as observed by Boisgeraud, they are all confirmatory of Prof. Oersted’s statement (“Ency. Met.” (Electro.-Mag.), Vol. IV. p. 6).

One month later, Nov. 9, 1820, Boisgeraud reads, before the same Académie, his paper “On the Action of the Voltaic Pile upon the Magnetic Needle,” which will be found on pp. 203–206 and 257, 258, Vol. LVII of the Philosophical Magazine.

=A.D. 1820.=--Banks (Sir Joseph) (1743–1820), a very eminent English naturalist and traveller, to whom reference has been made under the A.D. 1775 date, deserves mention here were it alone for the fact that while occupying the presidential chair of the Roy. Soc., during the extraordinary long and unequalled period of over forty-two years (1777, date of Sir John Pringle’s retirement, to 1820, the date of President Banks’ death) he was instrumental in bringing prominently before the world many of the most important discoveries and experiments known in the annals of magnetism and electricity.

Sir Joseph Banks was succeeded in the presidency of the Royal Society by William Hyde Wollaston, M.D., June 29, 1820, and by Sir Humphry Davy, Bart., Nov. 30, 1820, the last named holding the office seven years (R. Weld, “Hist. Roy. Soc.,” 1848, Vol. II. p. 359). Banks and Dr. Solander, the pupil of Linnæus, had sailed (1768–1771) with Captain Cook in his voyage around the globe, in the capacity of naturalists, and afterwards (1772) visited Iceland, where they made many important discoveries. In 1781 Banks was created a baronet; he received the Order of the Bath in 1795 and subsequently had many honours conferred upon him by different English and foreign societies. It is said that he was never known to be appealed to in vain by men of science, either for pecuniary assistance or for the use of his extensive library.

REFERENCES.--Tilloch’s Phil. Mag. for 1820, Vol. LVI. pp. 40–46; “Cat. Sci. Papers Roy. Soc.,” Vol. I. p. 176; Dr. Thomas Thomson, “Hist. Roy. Soc.,” London, 1812, p. 12; Gentleman’s Magazine for 1771, 1772 and 1820; “Biog. Univ.,” Vol. LVII, Suppl. p. 101; Larousse, “Dict. Univ.,” Vol. II. p. 155; “Eloge Historique de Mr. J. Banks, lu à la Séance de l’Académie Royale des Sciences, le 2 Avril 1821”; Sir Everard Home, “Hunterian Oration,” Feb. 14, 1822. See besides, the Phil. Mag., Vol. LVI. pp. 161–174, 241–257, for “A review of some of the leading points in the official character and proceedings of the late President of the Royal Society,” contrasting the respective personal merits and achievements of Sir John Pringle and of Sir Joseph Banks; “Lives of Men of Letters and Science,” by Henry, Lord Brougham, Philad., 1846, pp. 199–229, 294–295.

=A.D. 1820.=--Barlow (Peter), F.R.S. (1776–1827), who taught mathematics at the Military Academy of Woolwich from 1806 to 1847, brings out the first edition of his “Essay on Magnetic Attractions, Particularly as Respects the Deviation of the Compass on Shipboard Occasioned by the Local Influence of the Guns, etc., with an Easy Practical Method of Observing the Same in all Parts of the World.” One of his biographers states that through this valuable publication, which received the Parliamentary reward from the then existing Board of Longitude, as well as presents from the Russian Emperor, he was the first to reduce to strictly mathematical principles the method of compensating compass errors in vessels (Edin. Jour. of Sci., London, 1826, Vols. I. pp. 181, 182; II. p. 379).

This work contains the results of the many experiments to ascertain the influence of spherical and other masses of iron upon the needle, which Barlow instituted, more particularly after Prof. Hansteen’s investigations became generally known. Sir David Brewster details Barlow’s work in the “Encycl. Brit.,” and refers to the separate observations of Mr. Wm. Wales (at A.D. 1774), Mr. Downie (at A.D. 1790), Captain Flinders (at A.D. 1801), and Charles Bonnycastle (at A.D. 1820), mentioning the fact that it is to Mr. W. Bain we owe the distinct establishment and explanation of the source of error in the compass arising from the attraction of all the iron on board of ships. The small 140-page book which Mr. Bain published on the subject in 1817 is entitled “An Essay on the Variation of the Compass, Showing how Far it is Influenced by a Change in the Direction of the Ship’s Head, with an Exposition of the Dangers Arising to Navigators from not Allowing for this Change of Variation.” Brewster remarks that additional light was thrown upon Mr. Bain’s observations by Captains Ross, Parry and Sabine, but that we owe to Prof. Barlow alone a series of brilliant experiments which terminated in his invention of the neutralizing plate for correcting in perfect manner this source of error in the compass (Noad’s “Manual,” pp. 531, 532; Olmstead’s “Introduct. to Nat. Hist.,” 1835, pp. 206, 210). The simple contrivance therein alluded to is described and illustrated at pp. 9 and 90–91 of the “Britannica,” article on “Navigation,” and may briefly be said to consist of only a thin circular plate of iron placed in a vertical position immediately behind the binnacle or compass (Fifth Dissertation of “Britannica,” Vol. I. p. 745, and article “Seamanship,” in Vol. XX. p. 27). Such plates were immediately tried in all parts of the world and were at once applied to the English vessels “Conway,” “Leven” and “Barracouta” (Trans. Soc. of Arts for 1821, Vol. XXXIX. pp. 76–100; Harris’ “Rud. Mag.,” III. pp. 69–76; John Farrar, “Elem. of El. ...” 1826, pp. 376–383; Westminster Review for April 1825; “Encycl. Metropol.,” Vol. III (Magnetism), pp. 743, 799).

For Mr. Barlow’s experiments on the influence of rotation upon magnetic and non-magnetic bodies, the result of which was communicated by him to the Royal Society, April, 14, 1825, six days before the receipt of S. H. Christie’s paper “On the Magnetism of Iron, Arising from its Rotation,” communicated by J. F. W. Herschel, see pp. 10, 33, 34, of the “Britannica,” Vol. XIV above referred to (Edin. Jour. of Science, 1826, Vols. III. p. 372, and V. p. 214. Consult also, J. Farrar, “Elem. of El.,” 1826, pp. 387–395. For his extensive observations regarding the influence of heat on magnetism and relative to the variation, as well as for the mode of constructing his artificial magnets, consult the same volume of the “Britannica,” at pp. 35, 36, 50–53 et seq. and p. 73. See likewise, for the variation, Dr. Thomas Thomson’s “Outline of the Sciences,” London, 1830, pp. 549–556; Harris, “Rud. Mag.,” I, II. pp. 152–153. For Samuel Hunter Christie, consult “Abstracts of Papers ... Roy. Soc.,” Vol. II. pp. 197, 225, 243, 251, 270, 305, 321, 347 and 351).

The new variation chart which Prof. Barlow constructed and in which he embraced the magnetic observations made in 1832 by Sir James Ross, R.N., is described and illustrated in Phil. Trans. for 1833, pp. 667–675, Plates XVII, XVIII. He remarks that the very spot where his officer found the needle perpendicular, “that is, the pole itself, is precisely that point in my globe and chart in which, by supposing all the lines to meet, the several curves would best preserve their unity of character, both separately and conjointly as a system” (eighth “Britan.,” Vol. XIV, note, p. 50; Noad, “Manual,” p. 617; D. Olmstead, “Intr. to Nat. Phil.,” 1835, p. 192).

Mr. Barlow’s electro-magnetic globe was exhibited by Dr. Birkbeck in his lectures on “Electro-Magnetism” at the London Institution, May 26, 1824. (Its construction is fully described, more particularly, at p. 65 of the English “Encycl. Brit.” (Magnetism); p. 91 of the “Lib. of Useful Knowledge” (Electro-Magnetism); pp. 139–140, Vol. I of the Edin. Jour. of Science, London, 1826, and pp. 120–122, Part III of Harris’ “Rud. Mag.”) Its purpose was to show that what had hitherto been considered as the magnetism of the earth might be only modified electricity, and it was also intended to illustrate the theory advanced by M. Ampère, who, as is well known, attributed all magnetic phenomena to electric currents. In the words of Dr. Brewster:

“Barlow considers it as probable that magnetism as a distinct quality has no existence in Nature. As all the phenomena of terrestrial magnetism can be explained on the supposition that the magnetic power resides on its surface, it occurred to Mr. Barlow that if he could distribute over the surface of an artificial globe a series of galvanic currents in such a way that their tangential power should everywhere give a corresponding direction to the needle, this globe would exhibit, while under electrical induction, all the magnetic phenomena of the earth upon a needle freely suspended above it. Mr. Barlow says ‘he has proved the existence of a force competent to produce all the phenomena without the aid of any body usually called magnetic,’ yet he acknowledges that ‘we have no idea how such a system of currents can have existence on the earth, because, to produce them, we have been obliged to employ a particular arrangement of metals, acids, and conductors.’”

Barlow was the first to test the practicability of Ampère’s suggestion that by sending the galvanic current through long wires connecting two distant stations, the deflections of enclosed magnetic needles would constitute very simple and efficient signals for an instantaneous telegraph (Ann. de Chimie et de Phys., 1820, Vol. XV. pp. 72, 73). He has thus stated the result: “In a very early stage of electro-magnetic experiments, it had been suggested (by Laplace, Ampère and others) that an instantaneous telegraph might be established by means of conducting wires and compasses. The details of this contrivance are so obvious, and the principle on which it is founded so well understood, that there was only one question which could render the result doubtful; and this was, is there any diminution of effect by lengthening the conducting wires? It had been said that the electric fluid from a common (tinfoil) electric battery had been transmitted through a wire four miles in length without any sensible diminution of effect, and, to every appearance, instantaneously; and if this should be found to be the case with the galvanic circuit, then no question could be entertained of the practicability and utility of the suggestion above adverted to. I was therefore induced to make the trial; but I found such a sensible diminution with only 200 feet of wire, as at once to convince me of the impracticability of the scheme. It led me, however, to an inquiry as to the cause of the diminution, and the laws by which it is governed.” This passage is quoted in “Smithsonian Report” for 1878, p. 279; Fahie, “Hist. El. Tel.,” p. 306; “Memor. of Jos. Henry,” 1880, pp. 223, 224, the last named containing the following footnote: “On the Laws of Electro-Magnetic Action,” Edinburgh Philosophical Journal, Jan., 1825, Vol. XII. pp. 105–113:

“In explanation and justification of this discouraging judgment from so high an authority in magnetics, it must be remembered that both in the galvanometer and in the electro-magnet, the coil best calculated to produce large effects was that of least resistance; which unfortunately was not that best adapted to a long circuit. On the other hand the most efficient magnet or galvanometer was not found to be improved in result by increasing the number of galvanic elements. Barlow in his inquiry as to the law of diminution was led (erroneously) to regard the resistance of the conducting wire as increasing in the ratio of the square root of its length” (pp. 110, 111 of the last-cited “Journal.)”]

Mr. Taylor justly adds that subsequent experiments have proved Ohm’s law (announced three years after Barlow’s) of a simple ratio of resistance to length as approximately correct.

REFERENCES.--G. B. Prescott, “The Speaking Telephone,” 1879, II; Sci. Am. Supp., Nos. 405, p. 6466; 453, p. 7235; 547, p. 8735: “Mem. of Jos. Henry,” 1880, pp. 83, 94, 144, 485, 487. See also, Poggendorff, Vol. I. pp. 102, 103; Whewell, “Hist. Ind. Sciences,” 1859, Vol. II. pp. 223, 224, 245, 254, 616; “Lib. Useful Knowledge” (Magnetism), p. 86 and (El. Mag.), pp. 7, 18, 22, 28; Sturgeon’s “Sci. Researches,” Bury, 1850, pp. 26, 29, 31, 298; Humboldt, “Cosmos,” 1849, Vol. I. p. 183; Mrs. Somerville, “On the Earth not a Real Magnet,” in the “Conn. of the Phys. Sci.,”; Phil. Mag., Vols. LV. p. 446; LX. pp. 241, 343; LXII. p. 321; Harris, “Rud. Mag.,” Part III. pp. 114–116; “Encycl. Metropol.,” Vol. IV (Elect. Mag.), pp. 1–40; “Abstracts of papers ... Roy. Soc.,” Vol. II. pp. 164, 197, 241, 318; “Cat. Sc. Papers ... Roy. Soc.,” Vol. I. pp. 182–184; “Bibl. Britan.,” Vol. XX, N.S. p. 127; “Edin. Phil. Journal,” 1824, Vol. X. p. 184 (alludes to papers of Barlow and Christie in Phil. Trans. for 1823, Part II).

Mr. Wm. Henry Barlow, second son of Peter Barlow, is the author of a treatise, “On the spontaneous electrical currents observed in the wires of the electric telegraph,” which was published in London during 1849 and appeared in Part I of the Phil. Trans., for that year. He is also the inventor of a new electrical machine alluded to herein at Hare (A.D. 1819), also at p. 130 of the “Annual of Sc. Disc.,” at pp. 76–77 of Noad’s “Manual,” and at p. 428, Vol. XXXVII of the “Philosophical Magazine.”

=A.D. 1820.=--Laplace (Pierre Simon, Marquis de) (1749–1827), a very distinguished French astronomer and mathematician, suggests for telegraphic purposes the employment of magnetic needles suspended in multipliers of wire, in place of the voltameters of Sömmering, and on the 2nd of October 1820 his theory is thus explained by Ampère in a paper read before the French Academy of Sciences:

“According to the success of the experiment to which Laplace drew my attention, one could, by means of as many pairs of live wires and magnetic needles as there are letters of the alphabet, and by placing each letter on a separate needle, establish, by the aid of a distant pile, and which could be made to communicate by its two extremities with those of each pair of conductors, a sort of telegraph, which would be capable of indicating all the details that one would wish to transmit through any number of obstacles to a distant observer. By adapting to the battery a keyboard whose keys were each marked with the same letters and establishing connection (with the various wires) by their depression, this means of correspondence could be established with great facility, and would only occupy the time necessary for pressing down the keys at the one station and to read off the letters from the deflected needles at the other.”

Laplace is, perhaps, best known by his “Traité de Mécanique Céleste,” the sixteen books and supplements to which are by many considered, next to Newton’s “Principia,” the greatest of astronomical works; a book which has been truly said to have had no predecessor and which has been called the crowning glory of Laplace’s scientific career. His next important work was the “Théorie Analytique des Probabilités,” the most mathematically profound treatise on the subject which had yet appeared, while his “Système du Monde” was called by Arago “one of the most perfect monuments of the French language.” By Prof. Nichols, Laplace is called “the titanic geometer”; by Mr. Airy “the greatest mathematician of the past age”; by Prof. Forbes “a sort of exemplar or type of the highest class of mathematical natural philosophers of this, or rather the immediately preceding age.”

Laplace also wrote, in conjunction with Lavoisier, a treatise “On the Electricity which Bodies Absorb when Reduced to Vapor” (Mém. de Paris for 1781). Prof. Denison Olmstead, treating of the origin of atmospherical electricity (“Introd. to Nat. Phil.,” 1835, pp. 158, 159), says: “Among the known sources of this agent none seems so probable as the evaporation and condensation of watery vapor. We have the authority of two of the most able and accurate philosophers, Lavoisier and Laplace, for stating that bodies in passing from the solid or liquid state to that of vapor, and, conversely, in returning from the aeriform condition to the liquid or solid state, give unequivocal signs of either positive or negative electricity,” and he adds, in a footnote:

“M. Pouillet has lately published a set of experiments, which seems to overturn Volta’s theory of the evolution of electricity by evaporation. He has shown that no electricity is evolved by evaporation unless some chemical combination takes place at the same time ...” (Thomson, “Outlines,” p. 440) ... “But we shall be slow to reject the results of experiments performed by such experimenters as Lavoisier and Laplace, especially when confirmed by the testimony of Volta and Saussure.”

With regard to the origin of meteorites, Laplace has advanced the very bold theory that they may be products of Lunar volcanoes, and Prof. Lockhart Muirhead stated that he would “present the reasoning upon which this extraordinary hypothesis is founded in the popular and perspicuous language of Dr. Hutton, of Woolwich: the respect due to the name of Laplace justifying the length of the extract,” which he gives at pp. 633–635, Vol. XIV of the 1857 “Britannica.”

REFERENCES.--Humboldt, “Cosmos,” London, 1849, Vol. I. pp. 108–109; Young, “Course of Lectures,” London, 1807, Vol. II. p. 501, alluding to “Zach. Mon. Corr.,” VI. p. 276, also to Gilbert, XIII. p. 353, 108, and stating that Olbers had suggested Laplace’s idea in 1795. See “Mem. of the Astronom. Soc. of London,” Vol. III. p. 395: Laplace, “Mem. de l’Institut” for 1809, p. 332; Dr. Young’s “Course of Lectures,” 1807, Vol. I. pp. 249, 250, 522; Vol. II. p. 466; Humboldt, “Cosmos,” London, 1849, Vol. I. pp. 28, 76, 130; Vol. II. p. 712; Lavoisier at A.D. 1781: Biot at A.D. 1803; Annal. de Ch. et Phys., Vol. XV. pp. 72, 73, and for Laplace and Lavoisier, see Delaunay, “Manuel ...” 1809, p. 178; “Mem. de l’Acad. des Sc.,” for 1781; “Journal des Savants,” for Feb. 1850 and Nov. 1887; Houzeau et Lancaster, “Bibl. Gén.,” Vol. II. p. 184; “Cat. Sc. Pap. Roy. Soc.,” Vol. III. pp. 845–848; Johnson’s “Cyclopædia,” pp. 1647–1650 and the “First Supplement,” p. 62.

For Laplace and Joseph Louis Lagrange, see “Mémoires de l’Institut,” Vol. III. p. 22; also “Pioneers of Science,” by Sir Oliver Lodge, London, 1905, Lecture XI, and for Lagrange, consult “Journal des Savants,” Sept. 1844, May 1869, August 1878, Sept. 1879, Sept. 1888 and Oct. 1892.

M. Cyrille Pierre Théodore Laplace, captain in the French navy, is the author of the “Voyage Autour du Monde ... sur la Corvette Favorite ...” and of “Campagne de Circumnavigation de la Frégate l’Artémise ...” published in Paris during the years 1833, 1839 and 1841.

Baron Jean Baptiste Fourier, celebrated French physicist (1768–1830) who, in 1827, succeeded Laplace as head of the Council of the Ecole Polytechnique (“Biog. Gén.,” Vol. XVIII. p. 346) says of his predecessor:

“Posterity, which has so many particulars to forget, will little care whether Laplace was for a short time minister of a great state. The eternal truths which he has discovered, the immutable laws of the stability of the world, are of importance, and not the rank which he occupied” (C. R. Weld, “Hist. Roy. Soc.,” Vol. II. p. 465). Fourier is the author of “Expériences thermo-électriques” (“Encycl. Brit.,” ninth ed., Vol. IX. p. 490; “Eng. Cycl.,” Biography, Vol. II. p. 977).

=A.D. 1820.=--Dutrochet (René Joachim Henri) (1776–1847) a distinguished French natural philosopher, and likewise medical adviser to the King of Spain, Joseph Bonaparte, publishes an interesting treatise on meteors, in conjunction with Mr. Nathaniel Bowditch, who had already written many very able papers on astronomical subjects and who afterwards translated the “Mécanique Céleste” of Laplace. Eight years later (1828) appeared Dutrochet’s “Nouvelles Recherches ...” wherein he attributes to electricity the direction taken by fluids through animal and vegetable membranes. The passage of a fluid from without inwardly he called endosmosis, and the passage of the fluid from within outwardly he termed exosmosis.

Of Dutrochet, Dr. John Hutton Balfour, of Edinburgh, makes mention when treating of the temperature of plants. He thus expresses himself: “While the nutritive processes are going on in the plant, there is a certain amount of heat produced. This, however, is speedily carried away by evaporation and other causes, and it is not easily rendered evident. Dutrochet, by means of Becquerel’s thermo-electric needle, showed an evolution of heat in plants. In doing this, he prevented evaporation by putting the plant in a moist atmosphere. In these circumstances the temperature of the active vegetating parts, the roots, the leaves, and the young shoots, indicated a temperature above the air of ½ to ¾ of a degree Fahrenheit. Van Beek and Bergsma, in their experiments on the Hyacinthus Orientalis and the Entelea Arborescens, found the proper heat of the active parts of plants about 1·8° F. above that of the air. The vital or proper heat of plants, according to Dutrochet, is found chiefly in the green plants, and it undergoes a quotidian paroxysm, reaching the maximum during the day, and the minimum during the night. When stems become hard and ligneous, they lose this vital heat. Large green cotyledons gave indications of a proper heat. The hour of quotidian maximum varied from 10 a.m. to 3 p.m. in different plants.”

It is stated by Becquerel that in the act of vegetation, the earth acquires continually an excess of positive electricity, while the bark and part of the wood receive an excess of negative electricity. The leaves act like the green part of the parenchyma of the bark--that is to say, the sap which circulates in their tissues is negative with relation to the wood, to the pith, and to the earth, and positive with regard to the cambium. The electric effects observed in vegetables are due to chemico-vital action, and he asserts that the opposite electric states of vegetables and of the earth give reason to think that, from the enormous vegetation in certain parts of the globe, they must exert some influence on the electric phenomena of the atmosphere.

REFERENCES.--Gmelin’s “Chemistry,” Vol. I. p. 447; “Biog. Gén.,” Vol. XV. p. 506; Poggendorff, “Annalen,” Vol. I. p. 663; Larousse, “Dict. Univ.,” Vol. VI. p. 1448; J. W. Ritter, in “Denkschr. d. Münch. Acad.” for 1814, and the eighth ed. of the “Ency. Brit.” Vol. XXI. p. 635, for observations concerning the mimosa pudica and the mimosa sensitiva; “Cat. Sc. Papers Roy. Soc.,” Vol. II. pp. 422–425; Vol. VI. p. 646; Vol. VII. p. 584; Poggendorff, Vol. I. p. 633; “Observations on the diurnal variation of the magnetic needle,” in Sturgeon’s “Annals,” Vol. VII. pp. 369–370, and in the Comptes Rendus, Vol. XII. p. 298, of Feb. 8, 1841; Burnet, “On the motion of sap in plants. Researches of Dutrochet on Endosmose and Exosmose ...” London, 1829 (“Phil. Mag. or Annals,” Vol. V. p. 389).

=A.D. 1820.=--Fresnel (Augustin Jean) (1788–1827), one of the most distinguished French mathematicians and natural philosophers, communicates a paper detailing his experiments for decomposing water by means of a magnet. He produced a current in an electro-magnetic helix enclosing a bar-magnet covered with silk, and on plunging the ends of the wire in water he observed some very remarkable effects which are set forth in the Annales de Chimie et de Phys., series 2, Vol. XV. p. 219.

REFERENCES.--“Eloge de Fresnel,” by Arago, in his “Œuvres,” Vol. I; Account of Fresnel’s life in the “Biog. Univ.;” Whewell, “Hist. of Induc. Sci.,” 1859, Vol. II. pp. 96, 102, 114–117; “Œuvres complètes d’Augustin Fresnel, publiées par les soins du Ministre de l’Instruction Publique,” Paris, 1870, in three vols.

=A.D. 1820.=--Sir Richard Phillips (1778–1851), communicates, July 11, to the Philosophical Magazine (Vol. LVI. pp. 195–200) a very interesting paper entitled “Electricity and Galvanism Explained on the Mechanical Theory of Matter and Motion.” After reviewing the then existing theories, he concludes by saying:

“Electricity is no exception to the mechanical principles of matter and motion, and in regard to the kindred phenomena of galvanism, I will content myself with observing that it is merely accelerated electricity, the interposing fluid being palpably decomposed and evolving the electrical powers, each term in the series of plates being a new impulse or power added to the previous one, till the ultimate effect is accelerated, like that of a body falling by the continuous impulses of the earth’s motions, or like a nail heated red-hot by accelerations of atomic motion produced by repeated percussions of a hammer.”

Consult “Bibl. Ital.,” Vol. XXVII. p. 107 for references to the “Annals of Philosophy,” in which he mentions an experiment upon a young poplar, “whereby it would seem that copper was imbibed in the branches, etc., from a solution placed at its roots, and that it was precipitated on a knife used to cut off a branch.”

=A.D. 1820.=--Brewster (Sir David) (1781–1868), a very distinguished English natural philosopher and writer, who had just founded the “Edinburgh Philosophical Journal” in conjunction with Prof. Robert Jameson, announces his discovery of the existence of two poles of greatest cold on opposite sides of the northern pole of the earth. By this he was, like other authors, led to the belief that there might be some connection between the magnetic poles and those of maximum cold, and he remarks (Noad “Manual,” London, 1859, p. 545, and article “Magnetism” in “Encycl. Brit.”): “Imperfect as the analogy is between the isothermal and magnetic centres, it is yet too important to be passed over without notice. Their local coincidence is sufficiently remarkable, and it would be to overstep the limits of philosophical caution to maintain that they have no other connection but that of accidental locality; and if we had as many measures of the mean temperature as we have of the variation of the needle, we might determine whether the isothermal poles were fixed or movable.” Similar opinions entertained by Dr. Dalton, Dr. Traill and Mr. Christie are also mentioned by Noad, who quotes from Oersted’s treatise on “Thermo-Electricity” the statement of the Danish philosopher “that the most efficacious excitation of electricity upon the earth appears to be produced by the sun, causing daily evaporation, deoxidation and heat, all of which excite electrical currents.”

From his able paper in the Edinburgh Philosophical Transactions for 1820, one is led to share Sir David Brewster’s belief “that two meridians of greatest heat and two of greatest cold are called into play, and that the magnetism of our globe depends in great measure upon electro or rather thermo-magnetic currents.” The electro-magnetic hypothesis was, he says, ably supported by Prof. Barlow in his paper “On the probable electric origin of all the phenomena of terrestrial magnetism,” communicated to the Phil. Trans. for 1831. Brewster thus locates the two poles of maximum cold: The American pole in N. Lat. 73, and W. Long. 100 from Greenwich, a little to the East of Cape Walker; the Asiatic pole in N. Lat. 73 and E. Long. 80, between Siberia and Cape Matzol, on the Gulf of Oby. Hence the two warm meridians will be in W. Long. 10 and E. Long. 170, and the two cold meridians in W. Long. 100 and E. Long. 80.

As has already been indicated (under A.D. 1717, Leméry), Sir David Brewster was the discoverer of the pyro-electrical condition of the diamond, the garnet, the amethyst, etc. His development of some of Haüy’s experiments led to a similar discovery, attaching to several mineral salts as well as to the plates and powders of the tourmaline, of the scolezite and the melozite; and he likewise experimented with the boracite, mesotype and with the several minerals and artificial crystals detailed at pp. 208–215, Vol. I of the Edin. Jour. of Science, London, 1826; and in Chap. II. s. 1, vol. viii of the eighth “Encycl. Brit.,” article on “Electricity.”

At Part I. chap. i. s. 6 of the last-named article will be found Brewster’s observations on the nature and origin of electrical light, his latest researches having been made, like those of Joseph von Fraunhofer (see A.D. 1814–1815), on the dark and on the luminous lines which appear in the spectrum formed from it by a prism.

During the year 1831 appeared Brewster’s “Treatise on Optics,” his “Life of Sir Isaac Newton,” and his “Letters on Natural Magic.” It is in one of the chapters of the last-named work that he treats of automatic talking machines and remarks: “We have no doubt that before another century is completed a talking and a singing machine will be numbered among the conquests of science.”

Brewster’s other scientific treatises are too numerous and cover too wide a range to be enumerated here. The “Catal. of Sci. Papers of the Roy. Soc.” (Vol. I. pp. 612–623) gives the titles of as many as 299 contributions made by him on important subjects, and he has had no less than 76 papers in the first 39 parts of the North British Review, 30 in the Phil. Trans. and 28 in the Edin. Review. They appear, in fact, in all the prominent publications of his time, and have won for him leading honours, more especially from the Edinburgh and Aberdeen Universities and the Scotch, Irish, English and French Societies, the French Academy of Sciences doing him the signal honour of selecting him as one of its eight foreign associates in place of Berzelius, deceased. Conjointly with Davy, Herschel and Charles Babbage, he originated the British Association during 1831, and it was in this same year that he was knighted and decorated by King William IV. He had been made a Fellow of the Royal Society of Edinburgh in 1808, and had during the same year undertaken the editorship of the “Edinburgh Encyclopædia of Sci., Lit. and Art.” This he continued for twenty-two years, after which he edited the Edin. Jour. of Sci., and also entered with Taylor and Phillips upon the editorship of the London and Edin. Phil. Mag. and Journal. Many of our readers will doubtless be glad to know that the last named was a continuation of the well-known Philosophical Magazine so often quoted in this “Bibliographical History.”

REFERENCES.--The obituary notice contributed by Dr. J. H. Gladstone to the proceedings of the Royal Society; Chemical News, Amer. reprint, Vol. II. pp. 198, 233; also p. 293 for accounts given by Sir J. Simpson and Prof. Fraser; J. Robison and Brewster, “A System of Mechan. Phil.,” London and Edin., 1822; Ferguson and Brewster’s “Essays and Treatises on Astr. Elect.,” etc., Edinburgh, 1823; Brewster’s several articles in the “Encycl. Britannica,” 7th and 8th editions, on “Electricity and Magnetism”; Transactions of the Roy. Soc. of Edinburgh, Vols. IX. 1821; XX. Part IV; Edin. Jour. of Sci., Oct. 1824, No. 2, p. 213; Noad, “Manual,” London, 1859, pp. 31, 32, 636–638; Harris, “Magnetism,” Part III. p. 119; Whewell, “Hist. of Induc. Sci.,” 1859, Vol. II. pp. 75, 81, 331, 332; the lectures delivered by Wm. A. Miller during 1867 before the Royal Institution of Great Britain.

Charles Babbage (1792–1871), a prominent English scientist who is mentioned above and who besides being one of the founders of the Royal Astronomical Society, as has already been stated, was also a founder of the British Association and the originator of the Statistical Society, is the author of valuable papers, exhibiting a wide range of learning and research--mainly on mathematical subjects and relating to magnetical and electrical phenomena--which have been published in the Reports of the Royal and other Societies (“English Cycl.,” Vol. I. p. 457; “Encyl. Brit.,” ninth ed., Vol. III. p. 178; Larousse, “Dict.,” Vol. II. pp. 5–6; account of Babbage’s work in C. R. Weld’s “Hist. Roy. Soc.,” Vol. II. pp. 369–391).

=A.D. 1820.=--Fisher (George) (1794–1873), who two years before had joined Captain David Buchan in his voyage to the Arctic regions, is the first to point out the true cause of the sudden alteration in the rates of chronometers at sea. “He observed,” says Dr. Roget, “that the chronometers on board the ‘Dorothea’ and ‘Trent’ had a different rate of going from that they had on shore, even when these vessels had been frozen in, and therefore when their motion could not have contributed to that variation; ... this effect could be attributed only to the magnetic action exerted by the iron in the ships upon the inner rim of the balance of the chronometers, which is made of steel. A similar influence was perceptible on placing magnets in the neighbourhood of the chronometers. This conclusion was confirmed by experiments made for this purpose by Mr. Barlow, who ascertained that masses of iron devoid of all permanent magnetism occasioned an alteration in the rates of chronometers placed in different positions in their vicinity.”

REFERENCES.--Fisher’s article “On the Errors in Longitude as Determined by Chronometers at Sea, Arising from the Action of the Iron in the Ships upon the Chronometers,” communicated by John Barrow, F.R.S., to the Phil. Mag., Vol. LVII. pp. 249–257. See besides, Edinburgh Jour. Sci., London, 1826, Vol. V. p. 224; Phil. Trans. for 1820, Part. II. p. 196, and the volume for 1833, relative to magnetical experiments; also the “Lib. U. K.” (Magn.), p. 63. For Capt. Buchan, consult Barrow’s “Chronological History of Voyages into the Arctic Regions.”

Mr. George Thomas Fischer (1722–1848) is the author of “A Practical Treatise on Medical Electricity” (Poggendorff, Vol. I. p. 756).

=A.D. 1820.=--Bonnycastle (Charles), Professor of Mathematics in the University of Virginia, treats of the distribution of the magnetic fluids in masses of iron, as well as of the deviations which they produce in compasses placed within their influence, at pp. 446–456, Vol. LV of Tilloch’s Philosophical Magazine.

He refers to the then recent publication of Peter Barlow’s “Essay on Magnetic Attractions,” containing the results of many experiments, made principally upon spheres of iron, as well as to Dr. Young’s views of the subject, which were printed by order of the Board of Longitude, and he says that the principle upon which he intends establishing his inquiry “is an extension of the law that regulates the action of electrified bodies upon conductors; which was first given by M. Poisson in the Memoirs of the Institute for 1811, and employed by him to determine the development of the electric fluids in spheres that mutually act on each other.”

The afore-named dissertation, at the time, called forth a rejoinder from a correspondent and a further communication from Mr. Bonnycastle, both of which appear at pp. 346–350, Vol. LVI of the same publication.

REFERENCES.--Silliman’s Journal, Vol. XL. p. 32; “Sketch of the Life of Chas. Bonnycastle,” by Thomas Thomson; Poggendorff, Vol. I. pp. 234, 235; article “Magnetism,” p. 9, Vol. XIV of the eighth “Britannica.”

=A.D. 1820.=--Harris (Wm. Snow), member of the College of Surgeons, and a very distinguished English scientist (1791–1867), proposes to the Board of the Admiralty his system of lightning conductors, of which an account appears at p. 231, Vol. LX of the Phil. Mag., as well as in a separate work published at London during 1822. This is followed by his “Observations on the Effects of Lightning ...” 1823, and by papers relative to the defence of ships and buildings from lightning, which were published, more particularly, in several numbers of the Nautical Magazine, the Phil. Mag., the Annals of Electricity, and in the Proc. Lond. Elec. Soc. for 1842, as well as in his “Record of Phil. Papers,” and under separate heads during many years between 1827 and 1854. One of his biographers remarks:

“His researches have gone far to remove certain popular errors as to what have been called ‘conductors’ and ‘non-conductors’ of electricity, and to show the inutility of the old form of lightning rod in the majority of cases; it being necessary, in place of such rod form, to link into one great chain all the metallic bodies employed in the construction of a building, thus providing a connection with these conductors between the highest parts and the ground, the single conductor, in one highest part, being possibly insufficient to divert the course of the fluid and protect the whole fabric. These general principles have been largely applied to the protection of the ships of the Royal Navy during the last five and twenty years, under his advice and direction; and, laying aside the opinions which had been commonly received, the masts themselves of a ship have all been rendered perfectly conducting by incorporating with the spars capacious plates of copper, whilst all the large metallic masses in the hull have been tied, as it were, into a general conducting chain, communicating with the great conducting channels in the masts, and with the sea. This may be considered as the greatest experiment ever made by any country in the employment of metallic conductors for ships, and the result has been to secure the navy from a destructive agent, and to throw new light upon an interesting department of science” (Whewell, “Hist. of Induc. Sci.,” Vol. II. pp. 199, 200; Phil. Mag. for March 1841; eighth “Encycl. Britannica,” Vols. VIII. pp. 535, 610, 611, and XX. p. 24; “Edin. Review” for Oct. 1844, Vol. LXXX. pp. 444–473).

Harris was the first, says Brewster, who introduced accurate quantitative measures into the investigation of the laws of statical electricity--the unit measure by which quantity is minutely estimated--and also the hydro-electrometer and scale-beam balance by which its intensity and the laws of attractive forces at all distances are demonstrated. Of not less value is the thermo-electrometer, by which the heating effects of given quantities of electricity are measured and rendered comparable with the varying conditions of quantity and intensity. Besides these instruments, we owe to Harris the discovery of a new reactive force, through which repulsion and other small physical forces are investigated and determined by means of his bifilar balance, founded upon the reactive force of two vertically suspended parallel threads when twined upon each other at a given angle, and acted upon by a suspended weight. With the aid of these instruments he has carried on a variety of important inquiries into the laws of electrical forces, and the laws and operations of electrical accumulation (eighth “Brit.,” Vol. VIII. p. 535). His papers on the subject appeared in 1825 and 1828, and a résumé of them is given by Noad (“Manual” 1859, pp. 35, 137–140), as well as in the “Electricity” article of the “Britannica,” both of which contain descriptions and illustrations of Harris’ unit jar and electro-thermometer.

During the year 1827 Mr. Harris published in the Trans. Roy. Soc. of Edinburgh his memoir entitled “Experimental Inquiries Concerning the Laws of Magnetic Forces,” which experiments were made by means of a new and very accurate apparatus invented by him for examining the phenomena of induced magnetism. The above was followed by two other memoirs, published in the Phil. Trans. for 1831, “On the Influence of Screens in Arresting the Progress of Magnetic Action ...” and “On the Power of Masses of Iron to Control the Attractive Force of a Magnet,” which are discoursed of in the “Britannica” article on “Magnetism,” wherein special treatment is also given more particularly to Mr. Harris’ researches concerning artificial magnets as well as the magnetic charge, the development of magnetism by rotation and the phenomena of periodical variations (“Rudim. Mag.,” Part III. p. 60; Fahie’s “Hist, of Elec. Tel.,” pp. 283, 284).

Besides additional apparatus named in the subjoined references Mr. Harris invented a very effective steering compass, of which an account is given in Part III. pp. 148–153, of his “Rudimentary Magnetism,” as well as at p. 594 of Noad’s “Manual,” at p. 105 of the “English Cyclopædia” (Arts and Sciences), Vol. III, and at p. 80, Vol. VIII, 1857, “Encycl. Britannica,” and he has also devised a magnetometer for the measurement of electric forces, of which the description and illustrations appear in the last-named publication as transcribed from Mr. Harris’ work already mentioned.

Mr. Harris was made a F. R. S. in 1831, and received the Copley medal four years later. It was in 1843 he published his well-known work “On the Nature of Thunderstorms,” the plans he advocated being adopted in 1847, when he received the order of knighthood as well as a large money grant from the English Government in acknowledgment of his scientific services. The following appears in the obituary notice of Sir Wm. Snow Harris, contributed by Mr. Charles Tomlinson to the Proceedings of the Roy. Soc. (XVI, 1868):

“Harris’ sympathies were with the Bennetts, the Cavendishes, the Singers, the Voltas of a past age. Frictional electricity was his forte and the source of his triumphs. He was bewildered and dazzled by the electrical development of the present day, and almost shut his eyes to it. He was attached too closely and exclusively to the old school of science to recognize the broad and sweeping advance of the new. He was not conscious even of being behind his age when he presented to the Royal Society in 1861 an elaborate paper on an improved form of Bennett’s discharger, and still less in 1864, when he discussed the laws of electrical distribution, and yet relied upon the Leyden jar and the unit jar.”

REFERENCES.--Trans. of the Plymouth Institution, also Trans. of the Roy. Soc. for 1834, 1836, 1839; “Eng. Encycl.” (“Common Electricity”), Vol. III. p. 801; W. A. Miller, “Elem. of Chem.,” 1864, p. 32. For descriptions of his bifilar balance see the eighth “Britannica,” Vol. VIII. p. 623; Harris, “Rud. Elec.,” p. 99, and “Rud. Magn.,” pp. 119, 120; Noad, “Manual,” pp. 26, 27, 37, 40, 41, 63, 580; C. Stahelin, “Die Lehre ...” 1852; P. Volpicelli, “Ricerche analitiche ...” Roma, 1865, while, for his balance electroscope and electrometers, see “Edin. Phil. Trans.,” Dec. 1831; eighth “Britannica,” Vol. VIII. pp. 540, 590, 620 622, 624; Harris, “Rud. Elec.,” pp. 99, etc.; the “Bakerian Lecture”; the “Report of British Association,” Dundee, 1867, for an able account of electrometers by Sir William Thomson. His electrical machine is described at pp. 74–76 of Noad’s “Manual,” as well as at p. 604, Vol. VIII of the 8th “Britannica,” the latter also giving, at p. 550, Harris’ experiments on the electrical attraction of spheres and planes. “Catal. Sc. Papers Roy. Soc.,” Vol. III. pp. 191–192; Lippincott’s “Biog. Dict.,” 1886, p. 1230; Biography in Harris’ “Frictional Electricity”; “Abstracts of Papers ... Phil. Trans., 1800–1830,” Vol. II. p. 298; Lumière Electrique for Oct. 3, 1891, p. 49; reprint of Sir Wm. Thomson’s “Mathematical Papers,” 1872; “Brit. Asso. Reports” for 1832, 1835, 1836; Edin. Phil. Trans. for 1834; Fahie’s “History,” p. 321; Edin. and London and Edin. Phil. Mag. for 1840; Phil. Trans., 1842; Phil. Mag. for 1856–1857, and Harris’ “Manuals of Electricity, Galvanism and Magnetism,” published in John Weale’s Rudimentary Series.

=A.D. 1820.=--Mitscherlich (Eilardt--Eilhert), Professor of Chemistry at the Berlin University, discovers what is called Isomorphism (isos, equal; morphe, form), showing that bodies containing very different electro-positive elements could not well be distinguished from each other; it was impossible therefore to put them in distant portions of the classification, and thus, remarks Whewell, the first system of Berzelius crumbled to pieces.

In other words, Mitscherlich was the first to draw attention to the fact that two bodies having the same composition could assume different forms; to this law Berzelius gave the name of Isomerism (isos, equal; meros, part).

Sir John Herschel makes particular mention (“Treatise on Light,” s. 1, 113) of Mitscherlich’s remarkable experiment with sulphate of lime--the alteration in the tints of which by heat, it is said, was first observed by Fresnel. This experiment was repeated by Sir David Brewster, and he discovered still more curious properties in glauberite, all of which are detailed in Vol. I. p. 417 of the London and Edinburgh Phil. Mag. for Dec. 1832.

REFERENCES.--“Cat. Sci. Papers Roy. Soc.,” Vol. IV. pp. 413–416; “Library Useful Knowledge” (Pol. of Light), p. 63; Poggendorff, Vol. II. pp. 160, 161; the very able treatise of Mr. J. Beete Jukes on “Mineralogical Science”; also Poggendorff’s Annalen, Vol. XV. p. 630, for Mitscherlich on the chemical origin of iron glance in volcanic masses.

=A.D. 1820.=--Ampère (André Marie) (1775–1836), one of the most distinguished philosophers of the century, Professor of Mathematical Analysis in the French Ecole Polytechnique (1809), afterwards Professor of Physics at the Collège de France, reads before the Académie Royale des Sciences, Sept. 18, 25, Oct. 9, 13, and Nov. 6, 1820, papers containing a complete exposition of the phenomena of electro-dynamics. His investigations were subsequently embodied in the “Recueil d’Observations ...” Paris, 1822, and were still further developed during 1824 and 1826, as shown through both his “Précis de la théorie ...” and “Théorie des Phénomènes Electro-Dynamiques.”

The news of Oersted’s discovery of the relation existing between the electric current and the magnet--the fundamental fact of electro-magnetism--was made known in July 1820, and the inquiry was at once taken up more particularly by Ampère, Arago, Biot, and Félix Savary in France, as well as by Berzelius, Davy, De la Rive, Cumming, Faraday, Joseph Henry, Schweigger, Seebeck, Sturgeon, Nobili and others throughout Europe and elsewhere. Of all these scientists, Ampère proved the most energetic, and, within three months of the announcement of Oersted’s discovery, his first memoir on the subject was publicly read in Paris.

In this first paper, Sept. 18, he explains the law determining the position of the magnetic needle in relation to the electric current, and he also makes known his intended experiments with spiral or helical wires, which he predicts will acquire and retain the properties of magnets so long as the electrical current flows through them. He likewise explains his theory of magnets, saying that if we assume a magnet to consist of an assemblage of minute currents of electricity whirling all with the same direction of rotation around the steel molecules and in planes at right angles to the axis of the bar, we will have an hypothesis which will account for all the known properties of a magnet. He constructed his spirals and helices, and to the astonishment of all, he produced magnets formed only of spools of copper wire traversed by electric currents. We can readily imagine, adds Prof. A. M. Mayer, the intense interest awakened by this discovery, a discovery which caused Arago to exclaim, “What would Newton, Halley, Dufay, Æpinus, Franklin and Coulomb have said if one had told them that the day would come when a navigator would be able to lay the course of his vessel without a magnetic needle and solely by means of electric currents?” “The vast field of physical science,” says Arago, “perhaps never presented so brilliant a discovery, conceived, verified and completed with such rapidity.” Thus Ampère became the author of a beautiful generalization, which not only included the phenomena exhibited by the new combinations of Oersted, but also disclosed forces existing in arrangements already familiar, although they were never detected till it was thus pointed out how they were to be looked for. His electro-dynamic theory of the action of currents and of magnets has been thought worthy of a place near the Principia of Newton ... it deservedly gained for him the title of the Newton of electro-dynamics, as he did for this branch of science even more than Coulomb had previously done for electro-statics (Profs. A. M. Mayer and W. B. Rogers, “Memorial of Jos. Henry,” 1880, pp. 81, 476; Lardner, “Lectures,” 1859, Vol. II. p. 120; Fahie, “Hist. Tel.,” p. 276).

The experiments of Oersted and Ampère were at once greatly extended by many scientists, among whom may be especially mentioned MM. Yelin, Bœckmann, Van Beek, De la Rive, Moll, Nobili, Barlow and Cumming. The last named apparently gave the earliest notice of the increased effects of a convolution of wire around the magnetic needle, and constructed the first astatic needle galvanometer (Trans. Camb. Soc., Vol. I. p. 279). The Chevalier Julius Konrad Yelin (1771–1826), German mathematician, ascertained that the electricity of an ordinary machine when passed along a helix, either in simple electrical sparks or by discharges from a battery, has the effect of rendering an included needle magnetic. According to Dr. Henry, M. Bœckmann found in varying these experiments that no modification of the effect is produced by altering the diameter of the helix from half an inch to thirteen inches. With a helix of thirty-four inches diameter, and a coated surface of 300 square inches, much less magnetism was, however, imparted; and with one of eighty-four inches it was scarcely perceptible. It was found that a needle outside of the helix was magnetized as much as one within; that after being once fully magnetized a continuation of the discharges diminished its power; and that five jars, each of 300 square inches, did not produce, by repeated discharges, much more effect than one of them (Poggendorff, Vol. II. p. 1382; Gilbert’s Annalen for 1820–1823).

In his second paper, Sept. 25 (Ann. de Chim. et de Phys., Vol. XV. pp. 59–170), Ampère makes known the results of his experiments on the mutual attractions and repulsions of electrical currents, showing conclusively that when the voltaic current is passed in the same direction through two parallel wires, so placed as to move freely, they attract each other, and that they are repelled if the currents are passed in opposite directions. Thus he establishes the second fundamental law of electro-magnetism, the first law, instituted as we have seen by Oersted, being that the magnetical effect of the electrical current is a circular motion around the current. In the last-named paper he also proposes the hypothesis of currents of electricity circulating from east to west around the terrestrial globe in planes at right angles to the direction of the dipping needle, to account for the phenomena of terrestrial magnetism (Roget, “Electro-Magn.,” p. 47).

In his third paper, Oct. 9, Ampère investigates the properties of currents transmitted through wires forming closed curves (courbes fermées) or complete geometrical figures, an inquiry also alluded to in another memoir read Oct. 30, 1820.

These papers were immediately followed by others, which engaged nearly all the sittings of the Academy between Dec. 4, 1820, and Jan. 15, 1821. In these he brings forth new confirmations of his theories, and reduces the phenomena of electro-magnetism to mathematical analysis.

Mr. Samuel Prime remarks (“Life of Morse,” 1875, p. 266) that the discovery of the action of the spiral coil upon the magnetic needle seems to have been independently made by Ampère in 1821:

“I showed that the current which is in the pile acts on the magnetic needle by the conjunctive wire. I described the instrument, which I proposed to construct, and, among others, the galvanic spiral. I read a note upon the electro-chemical effects of a spiral of iron wire, subjected to the action of the earth, directing an electric current as well as a magnet. I announced the new fact of the attraction and repulsion of two electric currents, without the intermediation of any magnet, a fact which I had observed in conductors twisted spirally (Tilloch’s Journal of Science, Vol. LVII. p. 47, 1821).

One of his biographers, Professor Chrystal says: “Scarcely had the news of Oersted’s discovery reached France, when a French philosopher, Ampère, set to work to develop the important consequences which it involved. Physicists had long been looking for the connection between magnetism and electricity, and had, perhaps, inclined to the view that electricity was somehow to be explained as a magnetic phenomenon. It was, in fact, under the influence of such ideas, that Oersted was led to his discovery. Ampère showed that the explanation was to be found in an opposite direction. He discovered the ponderomotive action of one electric current on another, and, by a series of well-chosen experiments, he established the elementary laws of electro-dynamic action, starting from which, by a brilliant train of mathematical analysis, he not only evolved the complete explanation of all the electro-magnetic phenomena observed before him, but predicted many hitherto unknown. The results of his researches may be summarized in the statement that an electric current, in a linear circuit of any form, is equivalent in its action, whether on magnets or other circuits, to a magnetic shell bounded by the circuit, whose strength at every point is constant and proportional to the strength of the current. By his beautiful theory of molecular currents, he gave a theoretical explanation of that connection between electricity and magnetism which had been the dream of previous investigators. If we except the discovery of the laws of the induction of electric currents, made about ten years later by Faraday, no advance in the science of electricity can compare for completeness and brilliancy with the work of Ampère. Our admiration is equally great, whether we contemplate the clearness and power of his mathematical investigations, the aptness and skill of his experiments, or the wonderful rapidity with which he elucidated his discovery when he had once found the clew.”

“Oersted,” remarks M. Babinet, “was the Christopher Columbus of magnetism; Ampère became its Pizarro and its Fernand Cortez.”

Of Ampère’s astatic needles, a description, taken from one of his memoirs (Ann. de Ch. et de Ph., Vol. XVIII. p. 320), appears at pp. 280–281 of Fahie’s “History” (Knight’s “Mech. Dict.,” 1874, Vol. I. p. 171, and Vol. II. p. 1181). For this greatly perfected form of galvanometer the credit has erroneously been given to Prof. Cumming, who first suggested the idea of neutralizing the directive force of the needle arising from the earth’s magnetism, which he did by placing a magnetized needle immediately beneath the movable or index needle. Fahie adds, in a footnote: “In Prof. Cumming’s paper ‘On the Connection of Galvanism and Magnetism,’ read before the Cambridge Philosophical Society, April 2, 1821, he described a near approach to the astatic needle. In order to neutralize the terrestrial magnetism he placed a small magnetized needle under the galvanometer needle” (Trans. Cam. Phil. Soc., Vol. I. p. 279). The credit of Ampère’s discovery is sometimes given to Nobili, as in Noad’s “Manual of Electricity,” London, 1859, p. 327; also Roget’s “Electro-Magnetism” in “Library of Useful Knowledge,” London, 1832, p. 42.

As has been already shown (Laplace, A.D. 1820), the first proposal to apply Oersted’s discovery to telegraphic purposes by substituting the deflection of the magnetic needle through electric currents for the divergence of the pith balls of the electroscope, was made by Ampère, in his Memoir of Oct. 2, 1820, which appears in the Comptes Rendus, and at p. 72, Vol. XV of the Annales de Chimie et de Physique. His plan, remarks Sabine, was, however, doomed to the same fate as that of Sömmering, of never coming into practice, and for the same reasons, principally the number of line wires. Had Ampère combined his system, or rather the one of Laplace, with that which Schweigger proposed of reducing Sömmering’s telegraph to two wires, or with any other using a code of signals, the problem of the electric telegraph would have been solved from the year 1820. Ampère makes no mention of surrounding the needles with coils of wire, as is so frequently stated by writers on the telegraph. Indeed he could not then have even heard of the galvanometer; for, although Schweigger’s paper on the subject was read at Halle on the 16th of September 1820, it was not published until the November following.

M. Jean Jacques Antoine Ampère (1800–1864), son of André Marie Ampère, was an accomplished scholar who succeeded François Andrieux as professor at the Collège de France and became a member of the French Academy in 1847.

REFERENCES.--For accounts of Ampère’s rotary magnet, electro-dynamic cylinders, revolving battery, and of his electripeter employed to alter rapidly the direction of the electric current in voltaic batteries, consult pp. 639, 640, 643, Vol. VIII of the eighth “Britannica.” Fahie, “Hist. of El. Tel.,” p. 303. See “Catal. Sci. Papers Roy. Soc.,” Vol. I. pp. 58, 61; Messrs. Sainte-Beuve et Littré’s account of his life and labours in the Revue des Deux Mondes for Feb. 15, 1837; “Notice sur M. Ampère,” par M. E. Littré, Paris, 1843; Arago’s “Eulogy on Ampère,” translated, at pp. 111–171 of the “Report of the Smithsonian Institution” for 1872. Consult also “Report Smiths. Instit.” for 1857, pp. 100–107; Ampère’s biography in the Sci. Am. Suppl., No. 674, p. 10760; also Ampère’s “Journal et Correspondance,” Poggendorff, Vol. I. pp. 39, 40; Address of His Royal Highness the Duke of Sussex to the Eng. Roy. Soc., 1836; Barlow on “Magnetic Attractions”: Comptes Rendus for 1838, Vol. VII. p. 81; Bibl. Univ., XX; Phil. Mag., Vols. LVI. p. 308; LVII. pp. 40–47, “On the Electro-Magnetic Experiments of Oersted and Ampère,” by Mr. Hatchett, and pp. 47–49; Ann. de Phys. de Bruxelles, Vol. VII; Ann. de Ch. et de Phys., XXIX; Du Moncel, Vol. III. p. 7; “Acad. de Paris,” Sept. 12, 1825; La Lum. Elect. for Oct. 31, 1891, p. 202; Roch, in “Zeitschr. f. Mathém.” 1859, p. 295; Roget on Ampère’s theory of Mag.; K. W. Knochenhauer, Pogg. Annal., XXXIV. p. 481; J. Marsh, “On a Particular Construction of M. Ampère’s Rotating Cylinder,” Phil. Mag., LIX. p. 433, 1822; Henn, “De Amperi principiis ...”; “Memorial of Joseph Henry,” 1880, pp. 59, 81; “Lib. of Use. Know.” (El. Mag.), pp. 24, 28, 83–92; Harris, “Rud. Elec.,” pp. 170, 171, and “Rud. Mag.,” p. 130; Noad, “Manual,” pp. 661–662, 861–864; “Encycl. Metrop.” (El. Mag.), Vol. IV. pp. 5–8; Highton, “Elec. Teleg.,” p. 39; Gmelin’s “Chemistry,” Vol. I. p. 317; Mrs. Somerville, “Conn. Phys. Sci.,” 1846, pp. 320, 321; Dr. Lardner, “Lectures,” Vol. II. p. 125; J. F. W. Herschel, “Prelim. Dis. Nat. Phil.,” 1855, p. 243; Whewell, “Hist. Induc. Sc.,” 1859, Vol. II. pp. 242, 246, 619; “Ann. of Sc. Disc.” for 1850, p. 129, and for 1865, p. 125; “Smithsonian Report” for 1878, p. 273; Sturgeon, “Sci. Researches,” Bury, 1850, pp. 12, 16, 29; Jour. Frankl. Inst. for 1851, Vol. XXII. p. 59; Turnbull, “El. Mag. Tel.,” 1853, pp. 55 and 221; (Vail’s “History,” pp. 133, 134; Prof. Henry’s Evid., 85a, record; Doct. Channing’s Ev., 47a, record; Hibbard, Ev., 31_a_. ...) See also Humboldt’s “Cosmos,” articles “Aurora Borealis,” “Volcanoes,” “Earthquakes”; Ampère et Babinet, “Exposé des Nouv. Déc. ... de Oersted, Arago, Ampère, Davy, Biot, Erman, Schweigger, De la Rive,” etc., Paris, 1822, translated into German “Darstellung der neuen ... dem Französischen,” Leipzig, 1822, and alluded to in Lumière Electrique for July 18, 1891, pp. 148, 149; Hachette et Ampère, “Sur les Expériences de Oersted et Ampère”: Journal de Physique for September 1820. Annales de Chimie for 1825; “Journal des Savants,” for June 1872; “Dict. Génér. de Biogr. et d’Histoire,” Paris, 2^e ed., pp. 85–86; “Collection de Mémoires relatifs à la Physique,” Paris 1885, 1887, Vols. II and III passim, as per indexes; “Amer. Journ. of Psychology,” Vol. IV. pp. 6–7.

For William Ritchie (1790–1837), the author of an able paper, “On electro-magnetism, and Ampère’s proposal of telegraphic communication by means of this power,” consult Phil. Trans. for 1833, p. 313; “Abstracts of Papers ... Roy. Soc.,” Vol. II. pp. 350, 382; Phil. Mag. or Annals, Vol. VII, 1830, p. 212; Phil. Mag. and Journal of Science, Vol. III, 1833, pp. 37, 122, 124, 145.

For Leopoldo Nobili (1784–1835), frequently mentioned above, consult “Bibl. Univ.,” Bruxelles, 1834 (Sc. et Arts), Tome LVI. pp. 82–89, 150–168; “Edin. Trans.” Vol. XII and Phil. Mag. Vol. XI, 1832, p. 359, for the account of experiments made by James David Forbes, similar to those of Nobili, wherein an electric spark was elicited from a natural magnet. For J. D. Forbes, see also Phil. Mag., 1832, Vol. XI. p. 359. For Nobili and Antinori, consult Phil. Mag., Vol. XI, 1832, pp. 401, 466; “Bibl. Britan.,” Vol. XXV, 1824, N.S. p. 38; Vol. XXIX, 1825, N.S. p. 119. For Antinori and Marchese Cosimo Ridolfi, consult “Bibl. Britan.” Vol. XVI, N.S., 1821, pp. 72–75, 101–118.

For Prof. James Cumming (1777–1861), also frequently named in above article, consult Phil. Mag., Vol. LX, 1822, p. 253; “Bibl. Britan.,” Vol. XXV, N.S., 1824, p. 104, for experiments of Cumming, Trail and Marsh; the investigations in the same line of Mr. Thos. Stuart being especially reported on in “Bibl. Britan.,” Vol. XXVII, N.S., 1824, pp. 199–206; “Dict. of Nat. Biog.,” Vol XIII. p. 296; “Edin. Phil. Journal,” 1824, Vol. X. p. 185; “Cat. Sc. Papers Roy. Soc.,” Vol. I. pp. 58–61; Vol. VI. p. 565; Vol. VII. p. 29; “Bibl. Britan.,” Vol. XVI, N.S. p. 309; Vol. XVII, N.S. p. 16; Vol. XIX. p. 244; Vol. XX. pp. 173, 258; Vol. XXIV. p. 109.

For Le Chevalier Julius Konrad von Yelin (1771–1826), consult “Bibl. Britan.,” Vol. XXIII, N.S., 1823, p. 38; Vol. XXIV, N.S., 1823, p. 253, and, especially, the important tract on the discovery of thermo-magnetism at p. 31 of his “Die Akademie der Wissenschaften und ihre Gegner,” Munich, 1822.

=A.D. 1820.=--Arago (Dominique François Jean), famous French astronomer, physicist and statesman (1786–1853), who at the early age of twenty-three had, besides being Assistant Astronomer to the Observatory, become the successor both of Lalande in the Academy of Sciences and of Monge in the chair of analytical mathematics at the Polytechnic School, and who, conjointly with Gay-Lussac, had founded the highly valued Annales de Chimie et de Physique in 1816, communicates to the French Institute, on the 25th of September 1820, his discovery that the electric current has the power of developing magnetism in iron and steel. Into the axis of a galvanic conductor made in the form of a coil, or helix, he placed a needle, the extremities of the wire coil being connected to the poles of a battery, and with this he proved that the wire not only acted on bodies already magnetized, but that it could develop magnetism in such as did not already possess the power. When soft iron was used, the magnetism given was only temporary, but on repeating the experiment, M. Arago succeeded completely in permanently magnetizing small steel needles. Arago’s paper on the subject appears at p. 94, Vol. XV of the Ann. de Ch. et de Ph., and it is said that at about the same time Dr. Thos. J. Seebeck (1770–1831), and Georg Friedrich Pohl (1788–1849) laid similar results before the Berlin Academy, also that Sir Humphry Davy independently made a like discovery, of which he advised Dr. Wollaston, Nov. 12, 1820. Reference to this fact has already been made at Davy, under date A.D. 1801, wherein it was stated that the latter had found iron filings to so adhere to the connecting wire as to form a mass ten or twelve times the thickness of the wire. This was also the case in the experiments of M. Arago, who, upon observing that the filings rose before coming in contact with the conjugate wire, drew the conclusion that each small piece of iron was converted into a temporary magnet. Thus was Arago led to the discovery of what is called magnetic induction by electric currents, or, in other words, that an electrical current passing through a conductor will induce magnetic action in such bodies near it as are capable of being magnetized (Phil. Trans. for 1821, p. 9; Tilloch’s Jour. of Sci., Vol. LVII. p. 42, 1821; eighth “Britannica,” Vol. VIII. p. 532 and Vol. XIV. p. 640; Thomas Thomson, “Outline of the Sciences,” p. 563).

A fact worth noting in connection with the development of Oersted’s discovery by both Arago and Ampère, is that in order “to prevent the communication of the electricity laterally in the folds of the coil, the wire was insulated by varnish in the first instance and afterward by winding silk or cotton around it” (F. C. Bakewell, “Elec. Sci.,” London, 1853, p. 37).

On the 22nd of November 1824, Arago announced to the French Academy of Sciences the remarkable discovery made by him of a new source of magnetism in rotatory motion. He was led to this by observing that when a magnetic needle was oscillating above or close by any body, such as water or a plate of metal, it gradually oscillated in arcs of less and less amplitude, as if it were standing in a resisting medium, and, besides, that the oscillations performed in a given time were the same in number (Humboldt’s “Cosmos,” “Magnetic Observations,” 1825). He caused a circular copper plate to revolve immediately beneath a magnetic needle or magnet, freely suspended so that the latter might rotate in a plane parallel to that of the copper plate, and he found that the needle tends to follow the circumvolution of the plate; that it will deviate from its true direction, and that by increasing the velocity of the plate the deviation will increase till the needle passes the opposite point, when it will continue to revolve, and at last with such rapidity that the eye will be unable to distinguish it. This, says Mrs. Somerville, is quite independent of the motion of the air, since it is the same if a pane of glass be interposed between the magnet and the copper. When the magnet and the plate are at rest, not the smallest effect, attractive, repulsive, or of any kind, can be perceived between them. In describing this phenomenon Arago states that it takes place not only with metals, but with all substances, although the intensity depends upon the kind of substance in motion.

Arago’s experiments were repeated in London, March 7, 1825. His valuable discovery, which obtained for him the Copley medal, and which confirms the doctrine of the universal prevalence of magnetism in all bodies, is recorded in Arago’s “Sur les Déviations ... aiguille aimantée” (An. de Ch. et de Ph., Vol. XXXIII, and Phil. Trans., p. 467 for 1825), and a solution of the phenomena is given by Faraday in Phil. Trans. for 1832, p. 146, by Sir John Leslie in the Fifth Dissertation of the eighth “Britannica,” p. 746, as well as in the article “Magnetism” of the latter publication, and in Mrs. Somerville’s “Conn. of Phys. Sc.,” pp. 325–327. (See also the observations recorded in Humboldt’s “Cosmos,” 1849, Vol. I. pp. 172, 173; in Dr. Thomson’s “Outline of the Sciences,” pp. 556–558; Fahie, pp. 282, 283, 321; Dr. Whewell, Vol. II. pp. 254–256; Brewster’s Edin. Jour. of Sci., 1826, Vol. III. p. 179; “Dict. Gén. de Biogr. et d’Histoire,” Paris, 2^e ed. p. 126.)

In Brewster’s Edinburgh Journal of Science (Vol. V. p. 325), notice is given of Arago’s then recent researches on the influence which bodies considered not magnetic have on the motions of the magnetic needle, and reference is made to a new communication transmitted by Arago to the Académie des Sciences, as well as to a report of additional experiments in the same line given at meetings held July 3 and 10, 1826. Arago satisfactorily meets the denials made by Leopoldo Nobili and another Italian natural philosopher (Liberato Giovanni Bacelli) that substances not metallic have any influence on the magnetic oscillations, and he announces as a result of his investigations that, for certain positions of a vertical needle, and for velocities of rotation sufficiently rapid, the repulsive force which is exerted in the direction of the radius is as great as the force perpendicular to the radius, of which the effects are observed upon a horizontal needle.

Poisson having stated in his memoir “On the Theory of Magnetism” in motion (see Poisson at A.D. 1811) that Coulomb had recognized the magnetic virtue in all bodies, independently of the iron which they contain, Arago remarked that the idea of Coulomb was quite different from his, Coulomb having been of opinion that a quantity of iron, although too small for chemical analysis even to appreciate, was sufficient to produce in bodies which contained it appreciable magnetic effects. MM. Thénard and La Place confirmed this remark. Brewster adds that, in justice to Coulomb, it is necessary to state that he is the undoubted author of the discovery that all bodies, whether organic or inorganic, are sensible to the influence of magnetism. M. Biot has remarked that there are two ways of explaining this, either all substances in nature are susceptible of magnetism, or they all contain portions of iron, or other magnetic metals, which communicate to them this property. This last explanation, though adopted by Coulomb, by no means affects his claim to the discovery of the general fact that all bodies, whether organic or inorganic, are susceptible of becoming magnetic. Prof. Hansteen has drawn from numerous experiments and observations the important conclusion that every vertical object, of whatever material it is composed, has a magnetic south pole above, and a north pole below (Edin. Phil. Journal for January-April 1821).

M. Arago made many valuable investigations concerning the influence of the aurora borealis on the needle, on the variations of the latter, upon the nature of meteors, lightning, the zodiacal light, magnetic storms, etc. etc., which are admirably recorded more particularly in the great work of Alex. von Humboldt. The latter remarks that Arago has left behind him a treasury of magnetical observations (upward of 52,600 in number) carried on from 1818 to 1835, which have been carefully edited by M. Fédor Thoman, and published in the “Œuvres Complètes de François Arago” (Vol. IV. p. 493). Much could be said, especially regarding Arago’s paper, presented by him to the Academy of Sciences in 1811, which is considered to have established the foundation of chromatic polarization. Mention must at any rate be made of the fact that in Humboldt’s estimation the discovery of the two kinds of polarization of light may be considered the most brilliant of the century. They, unquestionably, rank among the most splendid of optical phenomena.

Etienne Louis Malus, a distinguished French philosopher (Fifth Dissert. of “Encycl. Brit.”), discovered in 1808 polarization by reflection from polished surfaces, and Arago, during 1811, made the discovery of coloured polarization. A world of wonder, remarks Humboldt, composed of manifold modified waves of light having new properties was now revealed. A ray of light which reaches our eyes, after traversing millions of miles from the remotest regions of heaven, announces of itself in Arago’s polariscope (consisting of a plate of quartz cut across the axis placed in one end of a tube, at the other end of which is a doubly refracting prism) whether it is reflected or refracted, whether it emanates from a solid or fluid, or gaseous body, even announcing the degree of its intensity (Delambre, “Histoire de l’Astronomie,” p. 652; Humboldt, “Cosmos,” 1849, Vol. I. p. 33; Vol. II. p. 715).

In 1818, Arago was elected a F.R.S.; he became a member of the Royal Astronomical Society and also member of the Bureau des Longitudes during 1822, was made Perpetual Secretary of the Academy and Director of the Paris Observatory eight years later, and received the Rumford medal in 1850. The Copley medal given him in 1825 had never before been conferred upon a Frenchman of science. It was upon his urgent request that the “Annuaire du Bureau des Longitudes” and “Les Comptes Rendus hebdomadaires” were commenced by the Academy, 1828–1835.

In a letter to Schumacher, Humboldt speaks of Arago as “one gifted with the noblest of natures, equally distinguished for intellectual power and for moral excellence.” In conjunction with Gay-Lussac, Arago was, for almost half a century, Humboldt’s most intimate friend, and their ever-increasing intimacy became such as to lead to a perfect unity of thought on scientific subjects. It cannot, therefore, be considered an exaggerated expression of feeling when, in a letter to Geoffroy St. Hilaire, dated Berlin, June 24, 1829, Humboldt should conclude with the words: “Pray remember me to MM. Valenciennes, Deleuze and Cuvier, but especially to him whom I hold dearest in this life, to M. Arago.”

REFERENCES.--Poggendorff, Vol. I. pp. 53, 54, and the several biographies named at p. 202, Vol. I of “Johnson’s New Univ. Cycl.,” 1877; J. A. Barral, “Œuvres de F. Arago,” 1854–1855; Faria E. De e Arago, “Breve compendio ...” Lisbon, 1800; Arago’s “Notices Scientifiques,” “Cat. Sc. Papers Roy. Soc.,” Vol. I. pp. 80–84; Vol. IV. pp. 697–701; Vol. VI. pp. 567, 736–737; Vol. VIII. p. 537; “Encycl. Metropol.,” Vol IV (Magnetism), pp. 6, 7; J. F. W. Herschel, “Nat. Phil.,” 1855, pp. 117, 244, and his account of the repetition of M. Arago’s experiments on rotatory magnetism in Phil. Trans. for 1825; Whewell, “Hist. Induc. Sci.,” 1859, Vol. II. p. 226; Phil. Mag., Vols. LIX. p. 233; LVII. pp. 40–49; LVIII. p. 50; LXI, p. 134; “Lib. Useful Knowledge’” (Magnetism), p. 91; Noad, “Manual,” pp. 204, 534; “Ann. of Sci. Disc.” for 1850, p. 124; Harris, “Rud. Magn.,” Parts I, II. pp. 58–61 and Phil. Trans. for 1831, Part I; Prime’s “Life of Morse,” pp. 168, 265, 266; Gmelin’s “Chemistry,” Vol. I. p. 317; Comptes Rendus for 1836, Vol. II. p. 212; Dredge, “Electr. Illum.,” Vol. II. p. 122; Sturgeon, “Scient. Res.,” Bury, 1850, pp. 13, 37, 216, etc.; Appleton, “New Am. Cycl.,” Vol. XI. p. 71; Sci. Am. Suppl., No. 204, p. 3254; La Lumière Electrique for Oct. 31, p. 202; “Reports of the Smithsonian Institution” for 1857, pp. 102, 107; for 1862, pp. 132–143, and p. 127 of last named for Malus’ discovery. Houzeau et Lancaster, “Bibl. Générale,” Vol. I. part. i. pp. 676–677 detailing the contents of Arago’s “Œuvres Complètes,” published in thirteen volumes under the direction of J. A. Barral, also Vol. II. p. 76; Cornhill Magazine, Vol. XVII. p. 727; Pierre Prévost, “Tentative,” Genève, 1822 (Poggendorff, Vol. II. p. 525); Phil. Mag., Vol. LVIII. p. 50; Vol. LXI. p. 134; “Abstracts of Papers ... Roy. Soc.,” Vol. II. p. 249.

=A.D. 1821.=--Ridolfi (Marquis Cosimo di), an Italian agriculturist, is the author of several treatises on fenomeni elettro-magnetici, published in Florence, wherein he expresses the belief that “because electricity produces both magnetic and calorific phenomena, the elements giving these separately may possibly be so compounded together as to produce electricity; which infers that electricity is a compound of magnetism and caloric.”

REFERENCES.--“Antologia di Firenze,” 1824, p. 159, and “Biblio. Ital.,” Vol. LXIII. p. 268 for Ridolfi’s description of the electric plate machine of Novellucci; also “Annales de Chimie et de Physique,” Vol. X. p. 287; Sturgeon, “Scientific Researches,” 1850, Sec. I. p. 29; “Bibliothèque Universelle” for Feb. 1821.

=A.D. 1821.=--Scoresby (Dr. William) (1789–1857), English master-mariner, and author of numerous scientific and other treatises, first publishes, in the “Trans. of the Edinburgh Society,” accounts of his magnetometer--magnetimeter--and of his electro-magnetic experiments. These were duly followed up by full reports of his many interesting investigations relative, more particularly, to the development of magnetic properties of metals by percussion, as well as to magnetic induction, and regarding the uniform permeability of all known substances to the magnet’s influence.

REFERENCES.--“Abstracts of Papers ... Roy. Soc.,” London 1832–1833, Vol. II. pp. 108, 168, 210; “Dict. of Nat. Biog.,” London, 1897, Vol. LI. p. 6; Phil. Trans. for 1822–1824; “Trans. Edin. Soc.,” Vol. IX. pp. 243–258, 353, 465; Vol. XI for 1824; Vol. XII for 1831; Vol. XIII for 1832, and Vol. XIV for 1833; “Brewster’s Jour. of Sc.,” Vol. VIII for 1828; “Bibliothèque Britannique,” Genève, 1796, N.S., Vol. XXIX for 1825, p. 185; “Edin. Phil. Jour.” for 1823, Vol. IX. p. 45.

=A.D. 1821.=--Babinet (Jacques) (1794–1872), French scientist, is the author of a very valuable treatise, published in Paris, upon the magnetical discoveries of Oersted, Ampère, Arago, Davy and others. This was followed by his “Résumé complet de la physique,” etc., and by a companion work treating of the relations of ponderable and imponderable bodies to the phenomena of magnetism and electricity, also, during the year 1829, by his Memoir upon the determination of terrestrial magnetism.

He succeeded Savary as Professor at the Collège de France in 1838, and, two years later, took the place of Dulong in the section of General Physics at the Académie des Sciences, becoming not long after the Assistant Astronomer at the Paris Observatory for Meteorology.

His numerous scientific treatises are to be found throughout the “Mémoires de la Société Philomathique,” the “Annales de Physique,” the “Comptes Rendus,” the “Revue des Deux-Mondes” and other prominent publications of the day.

REFERENCES.--Larousse, “Dict. Univ.,” Vol. II. p. 10; “Eng. Cycl.,” London, 1872, Supplement, p. 143; “Biog. Gén.,” Vol. IV. p. 21; Mme. Blavatsky, “Isis Unveiled,” Vol. I. p. 202; and Ronalds’ “Catalogue,” pp. 10–11, for the joint works of Ampère and Babinet.

=A.D. 1821.=--Pfaff (Christian Heinrich) (1773–1852), who became Professor of Medicine, Physics, etc., at the Kiel University, and was one of the most energetic followers of Volta, sends an unusually interesting communication to Gilbert’s “Annalen der Physik” and to Schweigger’s “Journal für Chemie und Physik,” wherein he very ably supports the views of the Pavia physicist.

Pfaff had, long before that, become favourably known through numerous scientific papers, which were translated into the leading foreign journals, the ones entitled “Dissertatio inauguralis ...” published at Stuttgart, and “Über thierische Elektricität,” published at Leipzig, having brought him special distinction. He had also written, more particularly, upon the experiments made by Alex. von Humboldt as well as relative to Pacchiani’s “Formation of Muriatic Acid by Galvanism,” alluded to at the A.D. 1805 entry, and it was by reason of the investigations made by Pfaff and Van Marum that the use of the voltaic column was generally abandoned. These scientists had constructed very strong piles consisting, in some instances, of as many as seventy large separate discs, when they found that the lower layers of wet cloth or of pasteboard were so seriously compressed by the discs above them as to neutralize their effect.

REFERENCES.--Johann Samuel T. Gehler’s “Phys. Wörterbuch,” Vol. VI. pp. 507, 517–518; “Roy. Soc. Cat. Sc. Papers,” Vol. IV. pp. 866–871; “Ann. der Chemie,” Vol. XXXIV. p. 307; Vol. LX. p. 314; “Annales de Chimie et de Physique,” Vol. XLI. pp. 236–247; Sturgeon, “Annals,” Vol. VIII. pp. 80, 146; Noad, “Manual,” p. 558; Wilkinson, “Elements,” Vol. I. pp. 1–8, 18, 22, 196, 326, 407; Vol. II. p. 106; “Encycl. Brit.” ninth ed., Vol. XVIII. p. 725; “Soc. Philom.,” Vol. II. p. 181; Phil. Mag., Vol. XXVII. p. 338.

=A.D. 1821.=--Faraday (Michael), a very distinguished English chemist and natural philosopher (1791–1867), who probably did more for the development of the study of electrical science than any other investigator, publishes his “History of the Progress of Electro-Magnetism” and succeeds, on the morning of Christmas (December 25), 1821, both in causing a magnetic needle to rotate round a wire carrying an electric current and in making the wire rotate around the needle, thus rendering possible the production of continuous mechanical motion by electricity.

The apparatus with which he produced this result is described in nearly all works treating of natural philosophy. Premising his reference to this discovery of Mr. Faraday, whose original papers thereon appear in the Quarterly Journal of Sciences and the Arts, Vol. XII. pp. 75, 186, 283 and 416 (the first bearing date September 11, 1821), Dr. Whewell says that on attempting to analyze the electro-magnetic phenomena observed by Oersted and others into their simplest forms, they appeared, at least at first sight, to be different from any mechanical actions which had yet been observed. It seemed as if the conducting wire exerted on the pole of the magnet a force which was not attractive or repulsive, but transverse; not tending to draw the point acted on nearer, or to push it further off, in the line which reached from the acting point, but urging it to move at right angles to this line. The forces appeared to be such as Kepler had dreamt of in the infancy of mechanical conceptions, rather than such as those of which Newton had established the presence in the solar system, and such as he, and all his successors, had supposed to be the only kinds of force which exist in nature. The north pole of the needle moved as if it were impelled by a vortex revolving round the wire in one direction, while the south pole seemed to be driven by an opposite vortex (called by Wollaston vertiginous magnetism and considered by Mr. Barlow as the result of tangential action). The case seemed novel, and almost paradoxical. It was soon established by experiments, made in a great variety of forms, that the mechanical action was really of this transverse kind. And a curious result was obtained, which a little while before would have been considered as altogether incredible: that this force would cause a constant and rapid revolution of either of the bodies about the other--of the conducting wire about the magnet, or of the magnet about the conducting wire (Vol. XII of the “Journal of the Royal Institution”; Watkins, “Popular Sketch of Electro-Magnetism; or Electro-Dynamics,” London, 1828; Mrs. Somerville, “Connection of Phys. Sciences,” 1846, p. 315).

Passing over many of Faraday’s important scientific investigations in other lines, we come to his second great discovery, that of magneto-electric induction, which is the converse of Oersted’s (developed by Ampère and Arago), the production of electricity by magnetism. This is recorded in the first series of “Experimental Researches in Electricity,” read November 24, 1831 before the Royal Society, of which body Faraday had become a Fellow during 1824, and it is published at p. 125 of the Phil. Trans. for 1832.

It appears that upon observing certain phenomena, which he described as Volta-electric, he concluded before long that magnetism in motion ought to produce an electric current just as electricity was made to imitate all the effects of magnetism. He carried on many experiments, and after the announcements made by Arago to the French Academy, November 22, 1824, he endeavoured to make the conducting wire of the voltaic circuit excite electricity in a neighbouring wire by induction, just as the conductor charged with common electricity would have done, but he obtained no satisfactory results until August 29, 1831 (Annales de Chimie, Vol. XLVIII. p. 402). He remarks: “Certain effects of the induction of electrical currents have already been recognized and described; as those of magnetism; Ampère’s experiments of bringing a copper disc near to a flat spiral; his repetition, with electro-magnets, of Arago’s extraordinary experiments, and perhaps a few others. Still it appeared unlikely that these could be all the effects which induction by currents could produce.... These considerations, with their consequence, the hope of obtaining electricity from ordinary magnetism, have stimulated me at various times to investigate experimentally the inductive effects of electric currents. I lately arrived at positive results, and not only had my hopes fulfilled, but obtained a theory which appeared to me to open out a full explanation of Arago’s magnetic phenomena, and also to discover a new state which may probably have great influence in some of the most important effects of electric currents.” His very important conclusion was finally verified, October 1–17, in the following manner. He had taken a helix, or spool of copper wire, which latter, Prof. Brande tells us, was covered with silk as in his former experiments and which was connected by its extremities with a galvanometer, the deflection of which would of course announce a current of electricity in the spiral and wires connected with it, and he found that while in the act of introducing the pole of a powerful bar-magnet within the coils of the spiral, a deflection of the galvanometer took place in one direction, and that when in the act of withdrawing, it took place in the opposite direction; so that each time the conducting wire cut the magnetic curves, a current of electricity was, for the moment, produced in it. Dr. Whewell’s account of the discovery is so well interspersed with references that it deserves repetition here:

“In 1831, Faraday again sought for electro-dynamical induction, and, after some futile trials, at last found it in a form different from that in which he had looked for it. It was then seen, that at the precise time of making or breaking the contact which closed the galvanic circuit, a momentary effect was induced in a neighbouring wire, but disappeared instantly (Phil Trans., 1832, p. 127, 1st ser., Art. 10). Once in possession of this fact, Mr. Faraday ran rapidly up the ladder of discovery, to the general point of view. Instead of suddenly making or breaking the contact of the inducing circuit, a similar effect was produced by removing the inducible wire nearer to or further from the circuit (Art. 18)--the effects were increased by the proximity of soft iron (Art. 28)--when the soft iron was affected by an ordinary magnet, instead of the voltaic wire, the same effect still recurred (Art. 37)--and thus it appeared, that by making and breaking magnetic contact, a momentary electric current was produced. It was produced also by moving the magnet (Art. 39)--or by moving the wire with reference to the magnet (Art. 53). Finally, it was found that the earth might supply the place of a magnet in this as in other experiments (2nd ser., Phil. Trans., p. 163) and the mere motion of a wire, under proper circumstances, produced in it, it appeared, a momentary electric current (Art. 141). These facts were curiously confirmed by the results in special cases. They explained Arago’s experiments: for the momentary effect became permanent by the revolution of the plate. And without using the magnet, a revolving plate became an electrical machine (Art. 150), a revolving globe exhibited electro-magnetic action (Art. 164), the circuit being complete in the globe itself without the addition of any wire; and a mere motion of the wire of a galvanometer produced an electro-dynamic effect upon its needle (Art. 171).... And thus he was enabled, at the end of his second series of ‘Researches’ (December 1831), to give, in general terms, the law of nature to which may be referred the extraordinary number of new and curious experiments which he has stated (Arts. 256–264), namely, that if a wire move so as to cut a magnetic curve, a power is called into action which tends to urge a magnetic current through the wire; and that if a mass move so that its parts do not move in the same direction across the magnetic curves, and with the same angular velocity, electrical currents are called into play in the mass. And here might properly be added the experimental distinction between a helix and a magnet, which Faraday subsequently pointed out (‘Exper. Res.,’ Art. 3273): ‘Whereas an unchangeable magnet can never raise up a piece of soft iron to a state more than equal to its own, as measured by the moving wire, a helix carrying a current can develop in an iron core magnetic lines of force of a hundred or more times as much power as that possessed by itself when measured by the same means.’”

An article on the reduction of Mr. Faraday’s discoveries in magneto-electric induction to a general law appeared in the “Philosophical Transactions of the Royal Society” Vol. III. p. 37, and at Vol. IV. p. 11, new series, of the Philosophical Magazine (see Faraday’s first two Memoirs in the Phil. Trans., Book XIII. chaps. v and viii; letter to Gay-Lussac in Annales de Chimie, Vol. LI. 1832, pp. 404–434; Phil. Mag., Vol. XVII. pp. 281, 356); while, in the Phil. Trans. for 1832, p. 132, is the Report of his production of the electric spark through a modified arrangement in which the electric current was induced by an electro-magnet, as shown in his subsequent work published in London during 1834. This is alluded to in Vol. V. pp. 349–354 of the Phil. Mag. for latter year, and in Poggendorff’s Annalen, Vol. XXXIV. pp. 292–301 for 1835. (See also Bakewell, “Elect. Science,” pp. 39, 140, 144.)

“Around the magnet, Faraday Is sure that Volta’s lightnings play; But how to draw them from the wire? He took a lesson from the heart ’Tis when we meet--’tis when we part, Breaks forth the electric fire.”

HERBERT MAYO, in Blackwood.

In Prof. Alfred M. Mayer’s address, delivered before the American Association at Boston, August 26, 1880, we read: “It is not generally known or appreciated that Henry and Faraday independently discovered the means of producing the electric current and the electric spark from a magnet. Tyndall, in speaking of this great discovery of Faraday, says: ‘I cannot help thinking while I dwell upon them, that this discovery of magneto-electricity is the greatest experimental result ever obtained by an investigator. It is the Mont Blanc of Faraday’s own achievements. He always worked at great elevations, but higher than this he never subsequently attained.’ And it is this same physicist who further remarks (‘Johnson’s Cycl.,’ Vol. II. pp. 26–27) that all our induction coils, our medical machines, and the electric light so far as it has been applied to lighthouses, are the direct progeny of Faraday’s discovery. In the paper here referred to (Nov. 24, 1831) he for the first time calls the ‘magnetic curves,’ formed when iron-filings are strewn around a magnet, ‘lines of magnetic force.’ All his subsequent researches upon magnetism were made with reference to those lines. They enabled him to play like a magician with the magnetic force, guiding him securely through mazes of phenomena which would have been perfectly bewildering without their aid. The spark of the extra current, which I believe was noticed for the first time by Prof. Joseph Henry, had been noticed independently by Mr. William Jenkin. Faraday at once brought this observation under the yoke of his discovery, proving that the augmented spark was the product of a secondary current evoked by the reaction of the primary upon its own wire.” The phenomenon of the spark from the extra current here alluded to was first announced by Henry in July 1832. He had observed that when the poles of a battery are united by means of a short wire of low resistance, no spark or at least a very faint one is produced, but when the poles of the battery are connected by a long copper wire and mercury cups, a brilliant spark is obtained at the moment the circuit is broken by raising one end of the wire out of its cup of mercury and also that the longer the wire and the greater the number of its helical convolutions, the more powerful would be the effect (Silliman, “Am. Jour. of Sc.,” Vol. XXII). The results of Faraday’s investigation of the extra current first appeared in the Phil. Mag. for November 1834.

The references already named give an account of many other important results attained by Faraday during 1831 and up to the date of the publication of the third series of his “Experimental Researches” (p. 76), wherein he recognizes the “Identity of Electricities derived from different sources”[60] (Vol. I. par. 265 and 360), after investigating the electricities of the machine, the pile, and of the electrical fishes, and after employing as conductors the entire plant of the metallic gas pipes and water pipes of the city of London (Phil. Trans. for 1833, p. 23; Poggendorff, Annalen, Vol. XXIX, 1833, pp. 274, 365).

In the fourth series, relating to “A New law of electric conduction” (Vol. I. par. 380, 381, 394, 410), he demonstrates the influence of what is called “the state of aggregation” upon the transmission of the current. He found that although the latter was conveyed through water it did not pass through ice. This he subsequently explained by saying that the liquid condition enables the molecule of water to turn round so as to place itself in the proper line of polarization, which the rigidity of ice prevents. This polar arrangement must precede decomposition, and decomposition is an accompaniment of conduction (Phil. Trans. for 1833, p. 507; Poggendorff, Annalen, Vol. XXXI, 1834, p. 225; also Phil. Mag., Vol. X. p. 98; “Royal Inst. Proc.,” Vol. II. p. 123; Silliman’s Journal, Vol. XXI. p. 368).

Other series (pars. 309, 450, 453–454, 472, 477, 661–662, 669, etc.) treat of “Electro-chemical or electrolytic decomposition.” The experiments of Wollaston in this line have been given under the A.D. 1801 date, where Prof. Faraday’s opinion of them is also expressed. Faraday was successful in the employment of Wollaston’s apparatus for the decomposition of water, and he afterwards devised an arrangement enabling him to effect true electro-chemical decompositions by common electricity as well as by the voltaic pile. For this, it is said, he used an electric battery consisting of fifteen jars and a plate machine having two sets of rubbers and a glass disc fifty inches in diameter, the whole presenting a surface of 1422 inches. One revolution of the plate could be made to give ten or twelve sparks, each one inch long, while the conductors afforded sparks ten to fourteen inches in length. He also devised a discharging train, to instantaneously carry off electricity of the feeblest tension by connecting a thick wire as he had previously done with the London gas and water pipes. A good description of the methods by which he succeeded with the latter apparatus in establishing the analogy between ordinary and voltaic electricity is given in the eighth “Britannica,” Vol. VIII. pp. 596–597. He had shown, at paragraph 371 and p. 105 of his “Researches,” that as a measure of quantity, a voltaic group of two small wires of platinum and zinc, placed near each other, and immersed in dilute acid for three seconds, yields as much electricity as the electrical battery, charged by thirty turns of a large machine; a fact that was established both by its momentary electro-magnetic effect, and by the amount of its chemical action, but, in order to enable him to establish a principle of definite measurement, he devised a voltameter or volta-electrometer as mentioned at paragraph No. 739 (Noad, “Manual,” p. 365). By means of this apparatus he calculated that a single grain of water in a voltaic cell will require for its decomposition a quantity of electricity equal to that liberated in 800,000 discharges of the great Leyden battery of the Royal Institution (“Researches,” par. 861). Also, that the decomposition of a single grain of water by four grains of zinc in the active cell of the voltaic circle, produces as great an amount of polarization and decomposition in the cell of decomposition, as 950,000 charges of a large Leyden battery, of several square feet of coated surface; an enormous quantity of power, equal to a most destructive thunderstorm. Tyndall remarks (“Notes on Electricity,” No. 118, also “Faraday as a Discoverer,” 1868, p. 44) that Weber and Kohlrausch ascertained that the quantity of electricity associated with one milligramme of hydrogen in water, if diffused over a cloud 1000 metres above the earth, would exert, upon an equal quantity of the opposite electricity at the earth’s surface, an attractive force of 2,268,000 kilogrammes.[61]

Faraday introduced new terms to express more specifically the circumstances attending electro-chemical decomposition. Objections had long been made to the designation poles--one positive, the other negative--on the ground that such did not convey a correct idea of the effects produced. These designations had been given under erroneous supposition that the poles exerted an attractive and repulsive energy towards the elements of the decomposing liquid, much as the poles of the magnet act towards iron. When connecting the extremities of a battery, the electricity simply makes a circuit; the current passes through the substance to be decomposed and the elements remain in operation until the connection is broken. Since the poles merely act as a path to the current he calls them electrodes (electron, electricity, odos, a way); that part of the surface of the decomposing matter which the current enters--immediately touching the positive pole--he designates as anode (ana, upward) and the part of the matter which the current leaves--next to the negative pole--cathode (kata, downward). He names electrolyte (luo, to set free) the fluid decomposed directly by electricity passing through it; the term electrolyzed meaning electro-chemically decomposed. The elements of an electrolyte are named ions (ion, going), the anion being the body (in sulphate of copper solution, the acid) which goes up to the positive pole, to the anode of the decomposing body, whilst the cation is that (in sulphate of copper solution, the metal) which goes down to the negative pole, to the cathode of the decomposing body.

The many tests which he made with his voltameter led him to the conclusion “that under every variety of circumstance, the decompositions of the voltaic current are as definite in their character as those chemical combinations which gave birth to the atomic theory” (Phil. Trans. for 1833, p. 675; for 1834, p. 77; Poggendorff, Annalen, Vols. XXXII. p. 401; XXXIII. pp. 301, 433, 481; Bakewell, “Electric Science,” p. 124; “Brit. Assoc. Report” for 1833, p. 393; Henry’s “Memoirs of Dalton,” p. 106).

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