Letters on natural magic, addressed to Sir Walter Scott

Letter I

Extent and interest of the subject — Science employed by ancient governments to deceive and enslave their subjects — Influence of the supernatural upon ignorant minds — Means employed by the ancient magicians to establish their authority — Derived from a knowledge of the phenomena of Nature — From the influence of narcotic drugs upon the victims of their delusion — From every branch of science — Acoustics — Hydrostatics— Mechanics — Optics — M. Salverte's work on the occult sciences — Object of the following Letters, 1

Letter II

The eye the most important of our organs — Popular description of it — The eye is the most fertile source of mental illusions — Disappearance of objects when their images fall upon the base of the optic nerve — Disappearance of objects when seen obliquely — Deceptions arising from viewing objects in a faint light — Luminous figures created by pressure on the eye either from external causes or from the fulness of the blood-vessels — Ocular spectra or accidental colours — Remarkable effects produced by intense light — Influence of the vi

CONTENTS.

imagination in viewing these spectra — Remarkable illusion produced by this affection of the eye — Duration of impressions of light on the eye — Thaumatrope — Improvements upon it suggested — Disappearance of halves of objects or of one of two persons — Insensibility of the eye to particular colours — Remarkable optical illusion described, ... 8

Letter III

Subject of spectral illusions — Recent and interesting case of Mrs A. — Her first illusion affecting the ear — Spectral apparition of her husband — Spectral apparition of a cat — Apparition of a near and living relation in grave-clothes seen in a looking-glass — Other illusions affecting the ear — Spectre of a deceased friend sitting in an easy chair — Spectre of a coach and four filled with skeletons — Accuracy and value of the preceding cases — State of health under which they arose — Spectral apparitions are pictures on the retina — The ideas of memory and imagination are also pictures on the retina — General views of the subject — Approximate explanation of spectral apparitions, ... 37

Letter IV

Science used as an instrument of imposture — Deceptions with plane and concave mirrors practised by the ancients— The magician's mirror — Effects of concave mirrors — Aerial images — Images on smoke — Combination of mirrors for producing pictures from living objects — The mysterious dagger — Ancient miracles with concave mirrors — Modern necromancy with them, as seen by Cellini — Description and effects of the magic lanthorn — Improvements upon it — Phan-

CONTENTS.

vii tasmagoric exhibitions of Philipstal and others — Dr Young's arrangement of Lenses, &c. for the Phantasmagoria— Improvements suggested — Catadioptrical phantasmagoria for producing the pictures from living objects — Method of cutting off parts of the figures — Kircher's mysterious handwriting on the wall — His hollow cylindrical mirror for aerial images — Cylindrical mirror for reforming distorted pictures — Mirrors of variable curvature for producing caricatures, . 56

Letter V

Miscellaneous optical illusions — Conversions of cameos into intaglios or elevations into depressions, and the reverse — Explanation of this class of deceptions — Singular effects of illumination with light of one simple colour — Lamps for producing homogeneous yellow light — Methods of increasing the effects of this exhibition— Method of reading the inscriptions of coins in the dark — Art of decyphering the effaced inscriptions of coins — Explanation of these singular effects — Apparent motion of the eyes in portraits — Remarkable examples of this — Apparent motion of the features of a portrait, when the eyes are made to move — Remarkable experiment of breathing light and darkness, . 98

Letter VI

Natural phenomena marked with the marvellous — Spectre of the Brocken described — Analogous phenomena — Aerial spectres seen in Cumberland — Fata Morgana in the straits of Messina — Objects below the horizon raised and magnified by refraction — Singular example seen at Hastings — Dover Castle seen through the hill on which it stands — Erect and inverted images viii

CONTENTS.

of distant ships seen in the air — Similar phenomena seen in the arctic regions — Enchanted coast — Mr Scoresby recognizes his father's ship by its aerial image — Images of cows seen in the air — Inverted images of horses seen in South America — Lateral images produced by refraction — Aerial spectres by reflexion,— Explanation of the preceding phenomena, 127

Letter VII

Illusions depending on the ear — Practised by the ancients— speaking and singing heads of the ancients — Exhibition of the invisible girl described and explained— Illusions arising from the difficulty of determining the direction of sounds — Singular example of this illusion — Nature of ventriloquism — Exhibitions of some of the most celebrated ventriloquists — M. St Gille — Louis Brabant — M. Alexandre — Captain Lyon's account of Eskimaux ventriloquists, . 157

Letter VIII

Musical and harmonic sounds explained — Power of breaking glasses with the voice — Musical sounds from the vibration of a column of air — And of solid bodies — Kaleidophone — Singular acoustic figures produced on sand laid on vibrating plates of glass — And on stretched membranes — Vibration of flat rulers, and cylinders of glass — Production of silence from two sounds — Production of darkness from two lights — Explanation of these singular effects — Acoustic automaton— Droz's bleating sheep — Maillardet's singing bird — Vaucanson's flute player — His pipe and tabor player — Baron Kempelen's talking engine — Kratzenstein's speaking machine — Mr Willis's researches, 1 79

CONTENTS.

ix

Letter IX

Singular effects in nature depending on sound — Permanent character of speech — Influence of great elevations on the character of sounds, and on the powers of speech — Power of sound in throwing down buildings — Dog killed by sound — Sounds greatly changed under particular circumstances — Great audibility of sounds during the night explained — Sounds deadened in media of different densities- — Illustrated in the case of a glass of champagne — And in that of new fallen snow — Remarkable echoes — Reverberations of thunder— Subterranean noises — Remarkable one at the Solfaterra — Echo at the Menai Suspension bridge — Temporary deafness produced in diving-bells — Inaudibility of particular sounds to particular ears — Vocal powers of the statue of Memnon — Sounds in granite rocks — Musical mountain of El-Nakous, . . 212

Letter X

Mechanical inventions of the ancients few in number — Ancient and modern feats of strength — Feats of Eckeberg particularly described — General explanation of them — Real feats of strength performed by Thomas Topham — Remarkable power of lifting heavy persons when the lungs are inflated — Belzoni's feat of sustaining pyramids of men — Deception of walking along the ceiling in an inverted position — Pneumatic apparatus in the foot of the house-fly for enabling it to walk in opposition to gravity — Description of the analogous apparatus employed by the gecko lizard for the same purpose — Apparatus used by the Echineis remora or sucking-fish, ...... 244

X

CONTENTS.

Letter XI

Mechanical automata of the ancients — Moving tripods — Automata of Daedalus — Wooden pigeon of Archytas — Automatic clock of Charlemagne — Automata made by Turrianus for Charles V. — Camus's automatic carriage made for Louis XIV. — Degennes's mechanical peacock — Vaucanson's duck which ate and digested its food — Du Moulin 's automata • — Baron Kempelen's automaton chess-player — Drawing and writing automata — Maillardet's conjuror — Benefits derived from the passion for automata — Examples of wonderful machinery for useful purposes — Duncan's tambouring machinery — Watt's statue turning machinery — Babbage's calculating machinery, . 264

Letter XII

Wonders of chemistry — Origin, progress, and objects of alchemy — Art of breathing fire — Employed by Barchochebas, Eunus, &c. — Modern method — Art of walking upon burning coals and red hot iron, and of plunging the hands in melted lead and boiling water — Singular property of boiling tar — Workmen plunge their hands in melted copper — Trial of ordeal by fire — Aldini's incombustible dresses — Examples of their wonderful power in resisting flame — Power of breathing and enduring air of high temperatures — Experiments made by Sir Joseph Banks, Sir Charles Blagden, and Mr Chantry, 297

Letter XIII

Spontaneous combustion — In the absorption of air by powdered charcoal— .And of hydrogen by spongy pla-

CONTENTS.

tinum — Dobereiner's lamp — Spontaneous combustion in the bowels of the earth — Burning cliffs — Burning soil — Combustion without flame — Spontaneous combustion of human beings — Countess Zangari — Grace Pett — Natural fire temples of the Guebres — Spontaneous fires in the Caspian Sea — Springs of inflammable gas near Glasgow — Natural light-house of Maracaybo — New elastic fluids in the cavities of gems — Chemical operations going on in their cavities — Explosions produced in them by heat — Remarkable changes of colour from chemical causes — Effects of the nitrous oxide or paradise gas when breathed — Remarkable cases described — Conclusion. . 313

LETTERS

ON

NATURAL MAGIC,

ADDRESSED TO

Sir WALTER SCOTT, Bart.

Letter I

Extent and interest of the subject — Science employed by ancient governments to deceive and enslave their subjects — Influence of the supernatural upon ignorant minds — Means employed by the ancient magicians to establish their authority— Derived from a knowledge of the phenomena of Nature— From the influence of narcotic drugs upon the victims of their delusion — From every branch of science — Acoustics — Hydrostatics — Mechanics — Optics — M. Salverte's work on the occult sciences — Object of the following Letters.

My Dear Sir Walter, As it was at your suggestion that I undertook to draw up a popular account of those prodigies of the ' material world which have received the appella-

A

LETTERS ON NATURAL MAGIC.

tion of Natural Magic, I have availed myself of the privilege of introducing- it under the shelter of your name. Although I cannot hope to produce a volume at all approaching in interest to that which you have contributed to the Family Library, yet the popular character of some of the topics which belong to this branch of Demonology may atone for the defects of the following Letters ; and I shall deem it no slight honour if they shall be considered as forming an appropriate supplement to your valuable work.

The subject of Natural Magic is one of great extent as well as of deep interest. In its widest range, it embraces the history of the governments and the superstitions of ancient times, — of the means by which they maintained their influence over the human mind, — of the assistance which they derived from the arts and the sciences, and from a knowledge of the powers and phenomena of nature. When the tyrants of antiquity were unable or unwilling to found their sovereignty on the affections and interests of their people, they sought to entrench themselves in the strongholds of supernatural influence, and to rule with the delegated authority of heaven. The prince, the priest, and the sage, were leagued in a dark conspiracy to deceive and enslave their species ; and man, who refused his submission to a being like himself, became the obedient slave of a spiritual despotism, and willingly bound himself in chains when they seemed to have been forged by the gods.

This system of imposture was greatly favoured by the ignorance of these early ages. The human mind is at all times fond of the marvellous, and the 3

RESOURCES OF THE ANCIENT MAGIC. 3

credulity of the individual may be often measured by his own attachment to the truth. When knowledge was the property of only one caste, it was by no means difficult to employ it in the subjugation of the great mass of society. An acquaintance with the motions of the heavenly bodies, and the variations in the state of the atmosphere, enabled its possessor to predict astronomical and meteorological phenomena with a frequency and an accuracy which could not fail to invest him with a divine character. The power of bringing down fire from the heavens, even at times when the elect: ic influence was itself in a state of repose, could be regarded only as a gift from heaven. The power of rendering the human body insensible to fire was an irresistible instrument of imposture ; and in the combinations of chemistry, and the influence of drugs and soporific embrocations on the human frame, the ancient magicians found their most available resources.

The secret use which was thus made of scientific discoveries and of remarkable inventions, has no doubt prevented many of them from reaching the present times ; but though we are very ill informed respecting the progress of the ancients in various departments of the physical sciences, yet we have sufficient evidence that almost every branch of knowledge had contributed its wonders to the magician's budget, and we may even obtain some insight into the scientific acquirements of former ages, by a diligent study of their fables and their miracles.

The science of Acoustics furnished the ancient sorcerers with some of their best deceptions. The

LETTERS ON NATURAL MAGIC.

imitation of thunder in their subterranean temples could not fail to indicate the presence of a supernatural agent. The golden virgins whose ravishing- voices resounded through the temple of Delphos ; — the stone from the river Pactolus, whose trumpet notes scared the robber from the treasure which it guarded ; — the speaking head which uttered its oracular responses at Lesbos ; — and the vocal statue of Memnon, which began at the break of day to accost the rising sun, — were all deceptions derived from science, and from a diligent observation of the phenomena of nature.

The principles of Hydrostatics were equally available in the work of deception. The marvellous fountain which Pliny describes in the Island of Andros as discharging wine for seven days, and water during the rest of the year ; — the spring of oil which broke out in Rome to welcome the return of Augustus from the Sicilian war, — the three empty urns which filled themselves with wine at the annual feast of Bacchus in the city of Elis, — the glass tomb of Belus which was full of oil, and which, when once emptied by Xerxes, could not again be filled, — the weeping statues, and the perpetual lamps of the ancients, — were all the obvious effects of the equilibrium and pressure of fluids.

Although we have no direct evidence that the philosophers of antiquity were skilled in Mechanics, yet there are indications of their knowledge, by no means equivocal, in the erection of the Egyptian obelisks, and in the transportation of huge masses of stone, and their subsequent elevation to great heights in their temples. The powers which they employed, and the mechanism by which they operated, have

RESOURCES OF THE ANCIENT MAGIC. 5 been studiously concealed, but their existence maybe inferred from results otherwise inexplicable, and the inference derives additional confirmation from the mechanical arrangements which seem to have formed a part of their religious impostures. When in some of the infamous mysteries of ancient Rome, the unfortunate victims were carried off by the g ods, there is reason to believe that they were hurried away by the power of machinery ; and when Apollonius, conducted by the Indian sages to the temple of their god, felt the earth rising and falling beneath his feet like the agitated sea, he was no doubt placed upon a moving floor capable of imitating the heavings of the waves. The rapid descent of those who consulted the oracle in the cave of Trophonius, — the moving tripods which Apollonius saw in the Indian temples, — the walking statues at Antium, and in the Temple of Hierapolis, — and the wooden pigeon of Archytas, are specimens of the mechanical resources of the ancient magic.

But of all the sciences Optics is the most fertile in marvellous expedients. The power of bringing the remotest objects within the very grasp of the observer, and of swelling into gigantic magnitude the almost invisible bodies of the material world, never fails to inspire wTith astonishment even those who understand the means by which these prodigies are accomplished. The ancients, indeed, were not acquainted with those combinations of lenses and mirrors which constitute the telescope and the microscope, but they must have been familiar with the property of lenses and mirrors to form erect and inverted images of objects. There is reason to think that they employed them to ef~

LETTERS ON NATURAL MAGIC.

feet the apparition of their gods ; and in some of the descriptions of the optical displays which hallowed their ancient temples, we recognize all the transformations of the modern phantasmagoria.

It would be an interesting pursuit to embody the information which history supplies respecting the fables and incantations of the ancient superstitions, and to show how far they can be explained by the scientific knowledge which then prevailed. This task has, to a certain extent, been performed by M. Eusebe Salverte, in a work on the occult sciences, which has recently appeared ; but notwithstanding the ingenuity and learning which it displays, the individual facts are too scanty to support the speculations of the author, and the descriptions are too meagre to satisfy the curiosity of the reader.*

In the following letters I propose to take a wider range, and to enter into more minute and popular details. The principal phenomena of nature, and the leading combinations of art, which bear the impress of a supernatural character, will pass under our review, and our attention will be particularly called to those singular illusions of sense, by which the most perfect organs either cease to perform their functions, or perform them faithlessly ; and where the efforts and the creations of the mind predominate over the direct perceptions of external nature.

* We must caution the young reader against some of the views given in M. Salverte's work. In his anxiety to account for every thing miraculous by natural causes, he has ascribed to the same origin some of those events in sacred history which Christians cannot but regard as the result of divine agency.

GENERAL OBJECT OF THE WORK. 7

In executing this plan, the task of selection is rendered extremely difficult, by the superabundance of materials, as well as from the variety of judgments for which these materials must be prepared. Modern science may be regarded as one vast miracle, whether we view it in relation to the Almighty Being, by whom its objects and its laws were formed, or to the feeble intellect of man, by which its depths have been sounded, and its mysteries explored : — And if the philosopher who is familiarized with its wonders, and who has studied them as necessary results of general laws, never ceases to admire and adore their author, how great should be their effect upon less gifted minds, who must ever view them in the light of inexplicable prodigies. — Man has in all ages sought for a sign from heaven, and yet he has been habitually blind to the millions of wonders with which he is surrounded. If the following pages should contribute to abate this deplorable indifference to all that is grand and sublime in the universe, and if they should inspire the reader with a portion of that enthusiasm of love and gratitude which can alone prepare the mind for its final triumph, the labours of the author will not have been wholly fruitless.

Letter II

The Eye the most important of our organs — Popular description of it — The eye is the most fertile source of mental illusions— Disappearance of objects 'when their images fall upon the base of the optic nerve — Disappearance of objects when seen obliquely — Deceptions arising from viewing objects in a faint light — Luminous figures created by pressure on the eye either from external causes or from the fulness of the blood-vessels— Ocular spectra or accidental colours — Remarkable effects produced by intense light — Influence of the imagination in viewing these Spectra — Remarkable illusion produced by this affection of the eye — Duration of impressions of light on the eye — Thaumatrope — Improvements upon it suggested — Disappearance of halves of objects or of one of two persons— Insensibility of the eye to particular colours — Remarkable optical illusion described.

Of all the organs by which we acquire a knowledge of external nature the eye is the most remarkable and the most important. By our other senses the information we obtain is comparatively limited. The touch and the taste extend no further than the surface of our own bodies. The sense of smellis exercised within a very narrow sphere, and that of recognizing sounds is limited to the distance at which we hear the bursting of a meteor and the crash of a thunderbolt. But the eye enjoys a boundless range of observation. It takes cognizance not only of other worlds belonging to the solar system,

POWER AND STRUCTURE OF THE EYE. 9

but of other systems of worlds infinitely removed into the immensity of space ; and when aided by the telescope, the invention of human wisdom, it is able to discover the forms, the phenomena, and the movements of bodies whose distance is as inexpressible in language as it is inconceivable in thought.

While the human eye has been admired by ordinary observers for the beauty of its form, the power of its movements, and the variety of its expression, it has excited the wonder of philosophers by the exquisite mechanism of its interior, and its singular adaptation to the variety of purposes which it has to serve. The eye-ball is nearly globular, and is about an inch in diameter. It is formed externally by a tough opaque membrane called the sclerotic coat, which forms the white of the eye, with the exception of a small circular portion in front called the cornea* This portion is perfectly transparent, and so tough in its nature as to afford a powerful resistance to external injury. Immediately within the cornea, and in contact with it, is the aqueous humour, a clear fluid, which occupies only a small part of the front of the eye. Within this humour is the iris, a circular membrane with a hole in its centre called the pupil. The colour of the eye resides in this membrane, which has the curious property of contracting and expanding so as to diminish or enlarge the pupil, — an effect which human ingenuity has not been able even to imitate. Behind the iris is suspended the crystalline lens in a fine transparent capsule or bag of the same form with itself. It is then succeeded by the vitreous humour, which resembles the transparent white of an egg, and fills up the rest of the eye. Behind the vitreous humour, there is spread out on the inside of the eye-ball a fine delicate membrane, called the retina, which is an expansion of the optic nerve, entering- the back of the eye, and communicating with the brain.

A perspective view and horizontal section of the left eye, shown in the annexed figure, will convey a popular idea of its structure. It is, as it were, a small camera obscura, by means of which the pictures of external objects are painted on the retina, and in a way of which we are ignorant, it conveys the impression of them to the brain.

Fig. I,

This wonderful organ may be considered as the sentinel which guards the pass between the worlds of matter and of spirit, and through which all their communications are interchanged. The optic nerve is the channel by which the mind peruses the handwriting of Nature on the retina, and through which it transfers to that material tablet its decisions and its creations. The eye is consequently the principal seat of the supernatural. When the indications of the marvellous are addressed to us through the

OCULAR ILLUSIONS.

ear, the mind may be startled without being deceived, and reason may succeed in suggesting some probable source of the illusion by which we have been alarmed : But when the eye in solitude sees before it the forms of life, fresh in their colours and vivid in their outline ; when distant or departed friends are suddenly presented to its view ; when visible bodies disappear and reappear without any intelligible cause ; and when it beholds objects, whether real or imaginary, for whose presence no cause can be assigned, the conviction of supernatural agency becomes under ordinary circumstances unavoidable.

Hence it is not only an amusing but an useful occupation to acquire a knowledge of those causes which are capable of producing so strange*a belief, whether it arises from the delusions which the mind practises upon itself, or from the dexterity and science of others. . I shall therefore proceed to explain those illusions which have their origin in the eye, whether they are general, or only occasionally exhibited in particular persons, and under particular circumstances.

There are few persons aware that when they look with one eye there is some particular object before them to which they are absolutely blind. If we look with the right eye this point is always about 15° to the right of the object which we are viewing, or to the right of the axis of the eye or the point of most distinct vision. If we look with the left eye the point is as far to the left. In order to be convinced of this curious fact, which was discovered by M. Mariotte, place two coloured wafers upon a sheet of white paper at the distance of three inches, and look at the left hand wafer with the right eye at the distance of about 11 or 12 inches, taking* care to keep the eye straight above the wafer, and the line which joins the eyes parallel to the line which joins the wafers. When this is done, and the left eye closed, the right hand wafer will no longer be visible. The same effect will be produced if we close the right eye and look with the left eye at the right hand wafer. When we examine the retina to discover to what part of it this insensibility to light belongs, we find that the image of the invisible wafer has fallen on the base of the optic nerve, or the place where this nerve enters the eye and expands itself to form the retina. This point is shown in the preceding figure by a convexity at the place where the nerve enters the eye.

But though light of ordinary intensity makes no impression upon this part of the eye, a very strong light does, and even when we use candles or highly luminous bodies in place of wafers the body does not wholly disappear, but leaves behind a faint cloudy light, without, however, giving any thing like an image of the object from which the light proceeds.

When the objects are white wafers upon a black ground, the white wafer absolutely disappears, and the space which it covers appears to be completely black ; and as the light which illuminates a landscape is not much different from that of a white wafer, we should expect, whether we use one or both eyes,* to see a black or a dark spot upon every land-

* When both eyes are open, the object whose image falls upon the insensible spot of the one eye is seen by the other, so that though it is not invisible, yet it will only be half as luminous, and therefore two dark spots ought to be seen.

DARK SPOT ON THE RETINA, &C. 13

scape, within 15° of the point which most particularly attracts our notice. The Divine Artificer, however, has not left his work thus imperfect. Though the base of the optic nerve is insensible to light that falls directly upon it, yet it has been made susceptible of receiving- luminous impressions from the parts which surround it, and the consequence of this is, that when the wafer disappears, the spot which it occupied, in place of being- black, has always the same colour as the ground upon which the wafer is laid, being white when the wafer is placed upon a white ground, and red when it is placed upon a red ground. This curious effect may be rudely illustrated by comparing the retina to a sheet of blotting-paper, and the base of the optic nerve to a circular portion of it covered with a piece of sponge. If a shower falls upon the paper, the protected part will not be wetted by the rain which falls upon the sponge that covers it, but in a few seconds it will be as effectually wetted by the moisture which it absorbs from the wet paper with which it is surrounded. In like manner the insensible spot on the retina is stimulated by a borrowed light, and the apparent defect is so completely removed that its existence can be determined only by the experiment already described.

Of the same character, but far more general in its effects, and important in its consequences, is another illusion of the eye which presented itself to me several years ago. When the eye is steadily occupied in viewing any particular object, or when it takes a fixed direction while the mind is occupied with any engrossing topic of speculation or of grief, it suddenly loses sight of, or becomes blind to, objects seen indirectly, or upon which it is not fully directed. This takes place whether we use one or both eyes, and the object which disappears will reappear without any change in the position of the eye, while other objects will vanish and revive in succession without any apparent cause. If a sportsman, for example, is watching with intense interest the motions of one of his dogs, his companion, though seen with perfect clearness by indirect vision, will vanish, and the light of the heath or of the sky will close in upon the spot which he occupied.