Elements of electricity and electro-chemistry

Front matter

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Preface

TUE Science of which a correct outline is attempted in the following pages, has been the subject of occastonal consideration for upwards of two centuries, but has rarely been the object of earnest and complete attention. The surprizing nature of tts phenomena, and the ease with which many of them are produced, have made it in the hands of the ionorant, and the empirical, a mere vehicle of shew and deception.

The attention of philosophers has indeed been occasionally directed to Electricity, as a promising source of discovery ; and after the immortal Franklin had demonstrated tts conao iv PREFACE.

nevion with atmospherical phenomena, it was always regarded as an important naturat agent. But the insulated nature of many of the observed facts, and the difficulty of referring them fo any simple general principle, continued to withhold from it that active and persevering cultiwation which is essential to the promotion, and correct opp ication of evert vy branch of science. |

The discovert y of the electrical powers of the Tor pedo, and the Gymnotus, the researches of Galvani on Animal Electricit: y, the mvention of the Voltaic Battery, and the discoveries with which it has so recently enriched and diversified Chemical Philosophy, have amply demonstrated the connection of Electricity with the most interesting subjects of experunental enquiry. Its importance 2s therefore sufficiently obvious, and no obstacle is opposed to its extenswe cultiwation but the present difficulty of attaining a competent acquaintance wth the various facts that have

PREFACE. Vv been already ascertained, and a just conception of their mutual relation and dependance.

There are deed many useful works on Electricity, but in the present eatended state of the Science a proper acquaintance with its principles can only be obiained by the laborious collection of its widely scattered materials ; which wt will then require considerable. attention to arrange, and tolerable skill to combine ; hence the appropriation of a portion of time is required for this purpose, which is incompatible with the. pursuats of many active and intelligent enqurers, and will be generally considered as inconvenient and objectionable,

To remove this difficulty is the principal object of the present work ;. and the devotion of a considerable portion of my life to the. practical consideration of the subject, with the constant habit of explanation and arrange» ment, in Lectures, authorizes an expectation that the attempt may be successful, “e

Vi PREFACE

By a@ proper attention to arrangement, f have been enabled to communicate a more exrtensive collection of facts in a single volume, than is to be found in any existing treatise with which I am acquainted ; and that attention may be expected to render even more concise statements amply intelligible ; for materials thus disposed, are like the combination of stones inan Arch; they mutually support each other, and form a connected series, in which every part is essential to the existence of the whole.

The experiments described, are sufficiently numerous, and some of them original; the simplicity by which many of the most essential ave characterized, will be advantageous to the student who may not have access to a regular apparatus, or to proper experimental lectures; and it will be of advantage to every one, to repeat as many of the described experiments as possible, during the regular perusal of the work,

PREFACE. Vil -

Some apology may be necessary for the free use of chemical terms; but this could not have been avoided without omitting a most essential part of the subject, and a sufficient explanation ef them, would have been too extensive for the limits of an elementary trea tise. Those whe are unacquainted with Chemistry, may prepare themselves for this part of the subject, by an attentive perusal of any of the very excellent works on that science, of which we have at present such numerous examples.

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Chap. I

Nature of Electrical Action, and Sources of Electrical | Excitation —Positive and Negative Electricity.

Production of electrical phenomena .........iecevecees 21 ROA CM BONDE ii caesy. bisa Sree Sus os ds,.0. i o'0 aCe, g 4.4 Hes ties

Electroscopes and electrometers .'......... Deen an Melee oe Cause of the divergence of electrified bodies ............ 24 Sources of electrical excitation.......... hes fae ways ha on ee Positive and negative electricity ............ tibisie'n stim sue” Oe

Method of distinguishing positive from negative ......... 29 Experiments on the production of positive and negative eleci Wis 06.6, sa 58 x Elie dn, kin ga vig pia amet telle nd, OO Their production is always contemporaneous ............ 32 Table of the effects of friction between various substances.. 33 | ‘av anous phenomena Of Xcialioy .. 4:+.-0<.n04 016. 9'h2 sont ns ae a wr

CONTENTS.

CHAP. AL

Of Conductors and Nonconductors of Electricity, and of the Electrical Apparatus.

Electrical effects are not transmitted by some bodies, but are conducted with more or less rapidity by others....... 36

Demonstration of the above ee Paces ais; * 5 "Table of conductors ........... ae ae 3g Weds 5 eas ae Table of nonconductors......... daatasrb waationatea nce bis ne a OO

Influence of heat, and moisture on nonconductors ........ 40 Remarkable changes produced by heat ......... .saeee0- 4L

Wature of electrical instillation 1.4... ues cswassccavsces 42 Experiments in illustration ...... ...... wg tns Goa le ivae AD Structure of the gold-leaf electrometer ..........-.. re Electrical apparatus in general....-........ ooo gees teen OO Plate-dlectfical machine 00.005. ia bee ondwdesoseuven, Cyhader clgemieak machine! 1.072000... LRT Ads is AB Proper construction of a cushion ..... ......+. secerecs AD Different methods of exciting glass ........ cae he tepeses 50

Necessary attention to tke electrical machine. .........0- 51 Receipt for the amalgam .......ceeesdeceee. 5

CHAP. it

Experiments with the Electrical Machine.—Theovry . of its Action.—Phenomena of Attraction and Ree cession.

Lines of light, and sparks produced by the action of an electrical wrath) “oo ae oe Se Rae a Oe ee Peculiarities attendant on these appearances . 3 38 pees Summary of the phenomena observed “_ se crsivon BAAS a tt Spotebel de Ae vntee ue sae res wes 55 Propositions a from those phenomena ............ ‘ib.

Be heory of ehecttical excitation SES ee ces eae Pe ee SF

Explanation of the action of the machine .........+0.... 48

CONTENTS. Xt

The phenomena produced by the action of a single electric Remade. arb AOL), § 0028 1 REST BG MEUeremrasalertras | 5 Demonstration of this fact by experiments......%.....+.. Ol Luminous appearance ef positive and negative points...... 62 Experiment with two hollow balls, a lighted taper, and phosphorus. ........... eB agSls URS eee) IB, Experiment on the transmission of electricity through rare- BENE Aion! h5 His RGR EIS A TORIES DA AOS Standards to which the different electrical states are referred 65 Motion of light bodies by electricity .......4+.s2cee000- 66 Illustration of electrical attraction ... .......00eeeeeeeee Ib. Illustration of electrical recession .......-0cccccccevrecs OF Bodies. similarly electrified recede from each other.—Bodies:

differently electrified attract each other ........... o.. 68 Inference from the preceding fact : entertaining experiments that depend on it ....+....... 1h 2 YU REAR ».- 69

Phenomena produced by electrical attraction ....+....+.. 70 Indications of the materiality of the electric fluid......... 72 Phenomena produced by the divergence of electrified bodies ib. Motion by electrified points ...... es capita na mebretone S

CHAP. IV.

On the Phenomena of Electric Light.

Circumstances essential to the production of electric light... 76 Causes by which its appearance is influenced ............ 77

Distribution of electricity on the surface of conductors... .. ib. Nature of the action of points........ EET a PET POR . Advantages of a spherical conductor ........ a ak ace 80

Effect of different sized balls, and of varieties in their situation, A single prominent point more active than seve- Febcumibigied:, 2.) Tee Ole LORE LPO

Effect of a point projected. more or less from the surface of acta ig.274) 2... EO) IPB, BO OPEB LS Nats

Action of different sized. conductors .... °.. 06. seeceas xl CONTENTS.

Methods of producing sparks of various length and density.. 83 Luminous brush of rays: effect of a point and a.ball.compared 84 Influence of surrounding bodies on the action of a point.—Increased electrical capacity by extension of surface...... 85 Effect of the transmitting conductor, and the density, &c. of the surrounding medium, on the brilliance of the spark.. 86

Zig-zag form of the long spark.—Its cause.........+... “87 Apparatus for procuring the electric spark in different gaseous mediums): -themsefiects ss io sae ait ated dis 2% Blas tan 88

Effect of the transmission of electricity through a barometri-

eal vacuum more or less rarefied ............¢. ides &Q Diffused transmission of electricity through highly rarefied air 90 Expetiment with a ball and silver thread .....-......... Ql Electric light similar to solar light: prismatic colours produced by a spark through wood ........... ae DO ib. Various appearances of the electric spark: electric illumi- NeNONS ae oc cetorwie des nodlia wd Losehies eaattiet Q2 Brilliant, effectsiof electric light .....ij.50 se tad ikcaRe 93 CHAP...V.

On the Leyden Jar, and the Nature of Electrical Influence.

Effect of opposing an insulated to an uninsulated conductor 95

Cause of the preceding elect. 2... <i. vss wie oe a ahee g6

Insulated conductors may be electrified to a greater extent when situated near those that are uninsulated ......... 97

Goated pane af.glase. 3h cr dead in See Ae eee 99 Construction of the Leyden jar. Electric shock ......... 100 Spontaneous explosion. Charging and discharging ....... 101

Discharging rod. Henley’s quadrant electrometer ..... .. 102 Coated surfaces charge more slowly than insulated conductors 103 A Leyden jar cannot be charged unless one of its surfaces communicates with the ground....... sell IINCEP For SOS If electricity be added to one surface of coated glass an equal quantity leaves the opposite surface .......scee0++0+ 105

CONTENTS. Xill

An insulated jar may be charged when its coating commuiicatestwitinahe rubber. FET ado we os BESTA Tales Action of the discharging rod.—Fracture of jars ™ a high charge.—Effect of jars of different thickness ..... A charged jar can only be discharged by a conducting communication from one of its surfaces to the other...... Jars charged and discharged by the contrary electricities. . Division of a charge.—Action of the metallic coating. . . Method of charging an uncoated jar......... 39 A OPIS The coating only a conductor to the charge ............ Permanence of the usual charge.—Construction of a Leyden phial which retains its charge in the pocket ......... Utility of varnishing the uncoated part of the glass.—Gene- PaVOoservations Ot theory”. os Go 1's see me req en ties The phenomena of charged jars analogous to other electrical operations.—Both sides of the jar evince the same electrical state whilst charging, but are found oppositely emciien when charged: «6. ¢ cai) yo )s sso aa eeteials wets Chae al A DIALS OF AE ce spe cr “se. catvete (40's Sosy 8s ee es Analogous phenomena of sparks, &C........6.65 ceeees Constraction of the electrophorus .......++..+++- ME bs Experiments with the reper Kia so asltss si andt Too pac Pacsye DE DRORy Of Mts DOM OI gos, atay aitarta, Ap BH ese ty’ siete bo seararen Construction of Volta’s condenser ......0ceeceeeeeesce Mr. Cavallo’ s improvement.— Combined condensers ..... Other instruments of greater sensibility but more equivocal Two methods of exciting electrical appearances ; first, by the actual communication of electricity ; second by its unequal distribution oe 4 hh dite aNa Chel 2 BXetedatanste tive eooe @ @ 0 @

Ils

117 118

421 122 123 126 128 129

XIV CONTENTS.

Part II. Of The Mechanical And Chemical Agencies Of Electricity

CHA 3.1

Instrumenis required for the Application of the Eleetric Power to the Purpose of Experiment.

General observations .......... ie sty Sede Se Eh rates pb 131 Construction of an electrical battery ........- SWIM Se mS Precautions to prevent spontaneous explosion .......+- .- 134 Proper thickness for the jars.—Lane’s electrometer...... 136 Description of Cuthbertson’s balance electrometer ....... 137 Distinction between quantity and Intensity.—Method of

forming a circuit ...... ats De Pee Aaah te ees 139 Flectricity passes through the best conductors and by the

shortest possible cofrsé) oo... ae. Sie es ace te wee Velocity of the electric discharge, and diglince 1 to which it

may be ediveyed: << aate state: & a wares ee 58s eet cote EE Measure’ of conducting power Tar. Awe cave cee cee 142 Construction of Henley’s universal discharger ..,....... 143 Regulation of the force of the electric spark.—Instruments

for ‘passing it through fluids or gases .... 000... e eee 144 Mechanical skill essential to an electrician. ..........6.. 145

CHAP. II. Mechanical Effects of Electricity

Mechanical power of the electric fluid inferred from its SAIS Hie sah ss

Perforation of compact bodies. —Paper ‘tofn . ..njled-. Feb 148

Brittle bodies broken. —Soft and fluid substances expanded 149 Fraciure of stout preces of glass... . 05. eacnwe +e Jo¥n SOO

Electrical artillery.—-Explosion over ice .........

CONTENTS. &¥

Warious expansive eftects.—Spark under water.......s0. 152 Spark under various finids.—Explosions over the surface of water and acids........ diag rps! $ am drloe ge diornsd vermegl SS Materiality of electricity.—Per ae OF P1458 v6 ceb+ene LSA Fracture of a small jar by the charge of a large one...... 156 Fusion of the coating at the point where the discharger is applied.—Soldered coin ........... «he ees Esa 157 Mechanical effects that indicate the course of the electric

fluid in the discharge ..... Se ae ee ee 158 Spontaneous discharge by a brush of rays .........2. 0+. 159 Spontaneous discharge in rarefied air.—Transmission of heat

in the direction of the electric fluid....... A eae 1606 Motion of a pith-ball during the discharge ..... ....... 10} The perforation of a card.—A bur is raised on each side by

SL (een eET SCE Stem ee ROME en RUE oaaa0, 108 Mr. Symmer’s experiment. rks Wristake: «06% ne Se

Course of the fluid shewn by the effect of a charge ona card coloured with vermilion......... Hy aetR | teeter Faves, ARO New mechanical demonstration of the course of the tna

Le 0 ee ae eee oe ae aed Ue Femeem Tha: ey mae 166 Another arr. angement for the same demonstration . ... 168 General remark on the preceding facts... 0.2 .cesseese 169

CHAP, III.

Chemical Effects of Electricity.

Light and heat frequently accompany the chemical action

of electricity =. 222 TPT as RN ee a heer 2d Inflammation of combustible bodies by electricity ....... 172 Similar effects produced on the surface of water.......°. 173 Metals melted and driven into glass and paper.......... 174 Designs impressed on silk or paper—Wire fused. ....... 175 Two inches of wire fused by a single jar charged to fifteen

grains of the balance electrometer.,........+ ihe 20 ee Eight inches of wire fused by the same jar charged to 30

grains; or by two jars charged to 15 BVAUIE 6: « 6 064, vexornt, & "9

X¥I CONTENTS.

Eighteen feet of wire melted at one explosion......... Thick jars charged to the same intensity do not melt the same length of wire as thin ones. —The fusion of wire a good measure of the quantity of electricity discharged from a jar or battery exo %®eoe6 Goer oeesevse e2 @ Oo eeee0e @ Various degrees of ignition.—Effect of different charges on an iron wire 7 6 8 eS @ fe. 9 0 6 e O 6 Choker eo 0.6.6 6) 6 C@e ere eee a @ ee

Production of metallic oxides by electricity... .......... Apparatus for exploding wire in a receiver ........0. eat Effects produced in such experiments .....3......4-00- Table of the comparative charges used to oxidate different wires.— Figures on paper and ast. SS. SRY o Ne ee Table of the comparative charges used to oxidate thinner and shorter wire.—Curious effect on a brass wire..... Revival of metals from their-owides yes seu a3 SORES Decomposition of water by electricity... ... nena eee Dr. Wollaston’s apparatus for decomposing water ....... Decomposition of oils, alcohol, and ether, &c......... Ge Separation of acid and alkali; and revival of metals from

their solations by electricity Piel ne SRA eS Composition of water from oxygen and hydrogen... .. Re

Inflammiable air pistol. —Inflammable air lamp........ 0. Composition of nitric acid from oxygen and nitrogen. .... Apparatus for experiments on the gases .........5.0 at Table of the results of electrifying various mixed gases. ... Table of the action of electricity on various compound gases Phosphoric effects produced by electricity ......... 006. Table of some phosphoric substances’ .........+e0ee0 0 Opaque bodies rendered, Jumtinousels.ni dsiau lees esndioes Relation of electricity to magnetism.—The magnetism proi duced by electricity deperds principally on the situation - of. the needle whilst. electrified... .../. fsceuid. sie a ee das

Magnetic polarity produced and reversed by electrical DSGhAESES ose loissvigie 05 oepeoeeoree oe carpe tFeeoeo Fanaa ot we

CONTENTS, XVIl

PART HT.

NATURAL AGENCIES OF ELECTRICITY,

25 Fe a apie ie

On the Identity of Electricity, and the Cause of Lightning.

THtrOdnerery ODSERVANGNS OTTO Ta gras Sa he oe gd o's 207

Conjectures of Mr. Grey and the Abbé Nollet . sa. Ug

Dr. Franklin’s comparison of the effects of slacintetly and SG Oa Mie i 42 22k Si ea aa Pe Se aah in GMM 1.05" 7 211

His proposed experiment to ascertain the identity of the electric fluid, and the cause of lightning.—Execution of this experiment by some members of the French aca- Eo POSEN oes SOAS 5 4 Sal es wk 213 Lightning drawn from the clouds by the English philosophers, and by Dr. Franklin.—Electrical kite. ........ 214 Remarkable experiment of M. de Romas.......... paet Hae Death of professor Richman.—Necessary precaution ..... 217 Franklin’s proposed defence for buildings frem injury by thunder storms’; 2s. Fa pie athtice ates ilies Saeee 218 ixperiments demonstrating its utility ...........-..0-. 219 ; Ditters applied toships i... ee sisal eal «gs eile aad Experiments on the influence of points ............... 222 Best method of constructing conductcrs for the defence of buildings from. daghaming .0'.7y Jeg loins oh ap ale, We Tahdig 224 Conimietors for emis 1 Po Baek viere vs we de ee es Oe . 225 General remarks on conductors....... OS ee ee . 226 Mr. Morgan’s proposed method of constructing them..... 227 Cause of chimneys being frequently struck ..... ee ask 228

- Method of fixing conductors.—Most effectual security for ShIpS eae pursing AB ak haten be ores eT ee trae ©",

*VI1i1 CONTENTS.

Defence for carriages. —Precautions for personal security.. 230 General remarks....... Bee «Aes 2 or re 7 éis.2 cee

CHAP. II.

On the Phenomena of Thunder Storms, and the probable Sources of Atmospherical Electricity.

The effects of the discharge of a thunder cloud and that of an electrical battery differ only in degree ............ 233

Varieties of the nome ot thunder. Ain8 og: ro, a ii oes 234 Method of calculating the distance of a thunder cloud.... 235 Different appearances of lightaing ch uid vieles duteewlesice 236 Relative action of the earth and clouds .............-.. 237

Volta’s experiment on the production of electricity by eva-

Cause of clouds and rain not satisfactorily explained...... 244 General observations on the phenemena of the atmosphere 246

CHAP, Tir.

On some luminous Phenomena of the Atmosphere, the Observation of Atmospherical LHlectricity, and the Arrangement of a new System of Insulation.

The aurora borealis, or northern lights... .. Lewcvoapat «te ghanwtaseus OOO

Reasons for ascribing them to electricity .............0. 251

Probable connection between the northern lights and the Parts MIB Ae TSI... as.4 isi, Sessa exvapee ele ane. gap Ws

CONTENTS. XIX

Description of a remarkable aurora by Mr. Dalton ....... 253 Brilliant appearance of the northern lights in the polar re- SIONS os cae Rie oka DR, ok ae aE Meese oO Peculiar noise said to accompany the northern lights ..... 257 Aurora Australis, or souther Hghts*P>.. /........:. 258 Meteors.—Characteristics of the larger ones which are sometimes attended by the fall of stones..... Age aes 2s wigs, erp Falling stars, or shooting stars. —Their peculiarities ...... 260 Occur in various weather, and sometimes are very numerous 201 Arguments in favour of their electrical origin.......... . 202 Imitation of the northern lights and falling stars......... 263 Electrical spark of five feet long »........0. 00.5. reve & 208

Other natural phenomena ascribed to electricity ......... 265 Observations on atmospherical electricity.—Construction of

CEOSSE 5 coc c Ce ee ne ORS Pelle wera late oa hrs ee 270 Results of various abservations on atmospherical electricity 272 Effect of a storm on the apparatus.......... MG Caiman. fs Characteristic electricity of Aifkevent kinds of tebe? . 274 Diurnal changes of atmospherical electricity ............ 275 Atmospherical apparatus of Mri Reade oy i acs cc cinie Fie: ZO Atmospherical apparatus by Mr. Cav ‘iia wal Mr. Bennett... 277 Arrangement of a new system of Insulation..... swans nomen Electrometer which preserves its insulation without wiping

EL Lo eee ay eee ee aieokiys. de Beloit revenst 17 Permanent insulator for an atmospherical apparatus...... 282 _ Experiments of Mr. Ronalds.—His plan for registering atmospherical changes during the absence of the obeX CONTENTS.

Chap. IV

Connection of Electricity with Medicine, and Nas tural History.

bal

Experiments of the Abbé Nollet............. ie sphere , 285 Acceleration of the motion of fluids in capillary tubes .... 286

Fiction Of the medicated tubes: 24... .; «ates 2 eel gare oe Medical application of electricity .0.0.0:65 203 see. s02 295 Proper machine and apparatus . diet igslst vie niiegace 1288 Mr. Morgan's opinion of the ere of cleceneiae 291 Brief enumeration of diseases in which electricity has fad successfully employed ............ , wrap siaries Ae 292

Effect of the electric tenets on various ett ae body... 295 Caution against the indiscriminate application of the aie

—Influence of electricity on vegetation.. ........... 296

Electrical powers of the torpedo, andthe pte chs 1.207 Bret deseription-of these animals...) wfc cide dem eee 208 Relation of their powers to other electrical phenomena... 300 Short account of the discovery of Galvanism...... «= SUR AS Os Muscular motion produced by electricity...... Poiana Pexperiozeat- with a M6) ces scp typ aeeanene oi8.,-

6 @8 ye. yetio (be) ee ve 303 Experiment with a flounder.—Preparation of the detached ,

Limbs cof At. 6 o.oo wis se Suoiaite yne ea os cole ae sai. OOM Muscular motion excited in the legs of a frog.—Experi-

ment-with a lesel’ ,. s-seb ea saews heen yt ~. s, BOS Galvanic sensations produced by the contact of zinc and

SIGE, fee este es Ee Ese eis Ee delle hehe tote 306 Hypothesis of Galvani opposed by Volta..............-. 307 Variogam-oltaic combinations. . 2... scastew whale ye Tang SOB:

Tables of Voltaic combinations by Sir H. Davy ......... 311 Volta on the comparative action of metals and fluids ....

Jnvention of the Voltaic pile . 4... Ss us s+ ba 2 0 « aioe

CONTENTS, XX

Part. IV. Voltaic Electricity

CHAP: cE pene ere of the Voltaic Apparatus, and Nature of its Electrical Phenomena.

Volta’s experiments on the electricity produced by the con-

tact of different kinds of metal......... Oe ae 315 Method of exhibiting the electricity of metals.... ..... 310 The same demonstration by metallic sieves and filings.... 318 © Probable cause of these effccts.— Metals by which they are mostureadily ObtamMed i. 6 a ee vl bee oe es 319 Experiment of Professor Robison........ ph ahat aera chy eke ib Construction of the Voltaic pile...... bes ois ID, 3a 321 Sheck irom. the Voltaic pile age oo ise fee BG 322 Construction of Cruickshank’s improvement of the Voltaic

APparatuUs. . +... ees ewes a ah ahs! Se Soiprreies arte ESL. eS Bhs 323 Construction of Volta’s ** Couronne des tasses”....... ¥'826 Method of combining different Voltaic batteries........ 328

Effect of different fluids in the Voltaic apparatus.—Its elec-

HENCAl. POWEF.....1 0. tsterval der dele vs CO SLA BO TOS 2G Influence of the exciting fluid on the tn deiaal power.... 330 Charge of an electrical battery by the Voltaic apparatus... 331 Experiments which prove there is an accumulation of power

by the charge of an electrical eid Mah etdile Ls oi S82 Probable cause of this phenomenon. . Beles Selene ah OOO Effects produced by different ceded “of fila des —Excita-

tion of muscular motion by Voltaic electricity........ 334 Most efficient apparatus for the production of pure electri-

XX CONTENTS.

CREA Pei Chemical Effects of the Voliaic Apparatus.

Difference between the chemical agency of Voltaic electri-

city and that of the common machine ........... . 338 Decomposition of water by the Voltaic apparatus...... .' 339 Separate collection of the elements of the decomposed body 342 Their appearance at a distance from each other.—Mr.

Cruickshank’s experjmenits {iiss Sav coward Sines ibe 1a. 343 Revival of metals, and transfer of acid and alkali by Voltaic

PlECIITGHyy ise lems eater aera (ee gah quater temeiaten is, 4 allt SA Experments-of( oat, (avy: i ..- thy ie Sad We Gem. 346 His discovery of the principles of Voltaic decomposition and

UAEISEOE i505; gs ones gs Poole, 2s Me bes yads. 4 JH 347

Transfer of the elements of compound bodies through men-

strua having a strong attraction for them............ 346 Constant appearance of ‘infamendle substances at the ne-

gative pole of the Voltaic apparatus ; and of oxygen or

its compounds at the positive surface.......... oseae O51 Hypothesis of natural electric energies ..... audetiun. 2 fe 352 Different electrical effects produced by the contact of a cop-

per-plate with, yanious bodies. 22. wee... 01+ RW oles 354 Electrical and chemical relations of different substances... $55 Illustration by the projection of various powders on an elec-

trifted surfaces; 4! cisucken th le ald Hore ail i PN: 356 Anomaly in these experiments. .... eee e eee n ee eee e eee 357 Analogy of electrical and chemical action —Chemical affi-

nity suspended or promoted by Voltaic electricity .... 359

Chemical effects of simple Voltaic combinations,....... 2860 Dr. Wollaston’s experiments and explanation ......... «+ 362 Qbyections to his hypothesigy... ...ccsceccw' Jewels vin Sata Ses 364

Experiment opposed to the explanation of Dr. Wollaston. 365

CONTENTS. XX

The chemical powers of the Voltaic apparatus are only pro-

duced when two metals communicate with each other

by the interposition of a fluid..... BP OP A, 39 POOR 3606 Experiments. by Mr, Sylvester...+-°.20. S20 Oe 367 Chemical phenomena explained by the preceding facts... 3069 Experiments on the revival of metals ..........+...+-++ 370 Consideration of the hypothesis of electric energy ...... 372 Different conditions for the electrical and chemical effects

of the. Voltaic apparatus... .:. s+ wee siete arrstetn Gh wale 374 The same chemical effects continue when the electrical

State of the wifes is vated JIG S00 Sey 0d 2 2 375 Curious experiments on the production of different chemi-

eal effects in various fluids, at every interruption of a mactallic ewowitam teal) Pf. 77g 2 Ee 376 Explanation of the distant separation of the elements of a

compound, on the hypothesis of electric energy.... .. 379 Different explanation by Dr. Bostock....°.......0..05 380

Revival of metal at every interruption in a metallic circuit. 382 Experiment. by Sir H. Davy@me.........2 6. 000505 HES aes General observations on the hypothesis of electric energy.. 384

CHAP. IIL.

Extensive Agency of the Voltaic Apparatus, as an dustrument of Analysis.—Its Influence in the Lvvoluiion of Light and the Production of Heat.

Invariable results of Voltaic decomposition, ............ 387 Decomposition of the alkalies Voi eee ei sreee 388 Properties of Potassium ....... Si New OCS © 3 ».. 389 Production and properties of sodium,..... SA Sp op aaa ae 390

Power necessary to decompose the alkalies... ...... ches OM

XXIV CONTENTS.

Amalgam of their bases with mercury.............++-. 394 Decomposition of the alkalies by heat.....++. .....e0. 395 Metallization of ammonia... ..4i0hom i on diate esbes ofthe BOT Nécomposition of the earths... 2. nnulse, Lib xa aaeeee General phenemena of Voltaic decomposition.......... 402 Evolution of brilliant light between charcoal points...... 403

Voltaic spark under various fluids ............. owes. 404 {ts action on compound gases.—Striking distance of the

WONG SWOT, aces ac a, wo cence oa RAR, SIE tas eee. 405 Intense heat produced by a powerful battery ........... 406 Its action on inflammable substances......... HRae Bo oe 407 Deflagration of various metals..../........ Pe Lote Fe 408 Continued ietiition-ofjwieys i. that. aaeuets on _oehs A 09 Experiment on the ignition of wire in rarefied air....... 410 Ratio in which the power of the apparatus increases, when

the number of plates is increased....... 5 Sahe phoiet E 411 Precautions necessary in experiments of this kind...,.... 413 Action of differentisized plates,. 3, se sgsny te. fhe state tek) See ¥ixperiment in illustration... bh =, Se RA Ra pebre 406

Igniting power of different bathe supposed to He as me squares of. the surfaces of the plates of which they are composed, taken individually 7"... 27. .).3. oid ao

Grand Voltaic apparatus of Mr. Children.......... oon

Large Voltaic apparatus constructed by order of the French government.—Experiments made with it......,.... 421

CONTENTS. XXV

CHAP. IV.:

Sketch of the State of Theoretical Knowledge. in Voltgic Hlectricity.—Structure and Properties of the Electric Column.

Elements of the Voltaic apparatus!) Uo All eae 8h 425 The contact of the different metals the primary source of iia Bleeirig Bower. ao.3.-) eh orae ae Ae me reh426

The power of the different pairs of metal is combined by

the conducting faculty of the interposed fluid........ 426 Electro-motive property of the Voltaic apparatus....,... 427 Analogous effects of the Voltaic battery, and ofa single pair of zine and:coppermpiaiaes sven. I PSR ete Y 428 Probable cause of the action of the Voltaic apparatus ..... 429 Correspondence of this opinjon with the phenomena..... 431 Cause of the ignition of Wifey. > WE BMF. 3. ARS ee 432