M. Seetzen throws out some conjectures respecting the cause of

these sounds. Does the rolling layer of sand, says he, act like the fiddle-bow, which, on being rubbed upon a plate of glass, raises and distributes into regular figures the sand with which the plate is covered? Does the adherent and fixed layer of sand perform here the part of the plate of glass, and the neighbouring rocks that of the sounding body? We cannot pretend to answer these questions, but we trust that some philosopher competent to the task will have an opportunity of examining these interesting phenomena with more attention, and describing them with greater accuracy. The only person, so far as I can learn, who has visited El-Nakous, since the time of Seetzen, is Mr. Gray, of University College, Oxford; but he has not added much to the information acquired by his predecessor. During the first visit which he made to the place, he heard at the end of a quarter of an hour a low continuous murmuring sound beneath his feet, which gradually changed into pulsations as it became louder, so as to resemble the striking of a clock, and at the end of five minutes it became so strong as to detach the sand. Returning to the spot next day, he heard the sound still louder than before. He could not observe any crevices by which the external air could penetrate; and as the sky was serene and the air calm, he was satisfied that the sounds could not arise from this cause.[30] [30] See _Edinburgh Journal of Science_, No. xi., p. 153, and No. xiii., p. 51. 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. The mechanical knowledge of the ancients was principally theoretical, and though they seem to have constructed some minor pieces of mechanism which were sufficient to delude the ignorant, yet there is no reason for believing that they had executed any machinery that was capable of exciting much surprise, either by its ingenuity or its magnitude. The properties of the mechanical powers, however, seem to have been successfully employed in performing feats of strength which were beyond the reach even of strong men, and which could not fail to excite the greatest wonder when exhibited by persons of ordinary size. Firmus, a native of Seleucia, who was executed by the Emperor Aurelian for espousing the cause of Zenobia, was celebrated for his feats of strength. In his account of the life of Firmus, who lived in the third century, Vopiscus informs us, that he could suffer iron to be forged upon an anvil placed upon his breast. In doing this he lay upon his back, and resting his feet and shoulders against some support, his whole body formed an arch, as we shall afterwards more particularly explain. Until the end of the sixteenth century, the exhibition of such feats does not seem to have been common. About the year 1703, a native of Kent, of the name of Joyce, exhibited such feats of strength in London and other parts of England, that he received the name of the second Samson. His own personal strength was very great; but he had also discovered, without the aid of theory, various positions of his body in which men even of common strength could perform very surprising feats. He drew against horses, and raised enormous weights; but as he actually exhibited his power in ways which evinced the enormous strength of his own muscles, all his feats were ascribed to the same cause. In the course of eight or ten years, however, his methods were discovered, and many individuals of ordinary strength exhibited a number of his principal performances, though in a manner greatly inferior to Joyce. Some time afterwards, John Charles Van Eckeberg, a native of Harzgerode, in Anhalt, travelled through Europe under the appellation of Samson, exhibiting very remarkable examples of his strength. This, we believe, is the same person whose feats are particularly described by Dr. Desaguliers. He was a man of the middle size, and of ordinary strength; and as Dr. Desaguliers was convinced that his feats were exhibitions of skill and not of strength, he was desirous of discovering his methods, and with this view he went to see him, accompanied by the Marquis of Tullibardine, Dr. Alexander Stuart, and Dr. Pringle, and his own mechanical operator. They placed themselves round the German, so as to be able to observe accurately all that he did, and their success was so great that they were able to perform most of the feats the same evening by themselves, and almost all the rest when they had provided the proper apparatus. Dr. Desaguliers exhibited some of the experiments before the Royal Society, and has given such a distinct explanation of the principles on which they depend, that we shall endeavour to give a popular account of them. [Illustration: _Fig. 52._] 1. The performer sat upon an inclined board A B, placed upon a frame C D E, with his feet abutting against the upright board C. Round his loins was placed a strong girdle F G, to the iron ring of which at G was fastened a rope by means of a hook. The rope passed between his legs through a hole in the board C, and several men or two horses, pulling at the other end of the rope, were unable to draw the performer out of his place. His hands at G seemed to pull against the men, but they were of no advantage to him whatever. [Illustration: _Fig. 53._] 2. Another of the German’s feats is shown in Fig. 53. Having fixed the rope above-mentioned to a strong post at A, and made it pass through a fixed iron eye at B, to the ring in his girdle, he planted his feet against the post at B, and raised himself from the ground by the rope, as shown in the figure. He then suddenly stretched out his legs, and broke the rope, falling back on a feather-bed at C, spread out to receive him. 3. In imitation of Firmus, he laid himself down on the ground, as shown in Fig. 54, and when an anvil A was placed upon his breast, a man hammered with all his force the piece of iron B, with a sledge hammer; and sometimes two smiths cut in two with chisels a great cold bar of iron laid upon the anvil. At other times a stone of huge dimensions, half of which is shown at C, was laid upon his belly, and broken with a blow of the great hammer. [Illustration: _Fig. 54._] 4. The performer then placed his shoulders upon one chair and his heels upon another, as in Fig. 55, forming, with his backbone, thighs, and legs, an arch springing from its abutments at A and B. One or two men then stood upon his belly, rising up and down while the performer breathed. A stone, one and a half feet long, one foot broad, and half a foot thick, was then laid upon his belly, and broken by a sledge-hammer; an operation which may be performed with much less danger than when his back touched the ground, as in Fig. 54. [Illustration: _Fig. 55._] 5. His next feat was to lie down on the ground, as in Fig. 56; a man being then placed on his knees, he draws his heels towards his body, and, raising his knees, he lifts up the man gradually, till having brought his knees perpendicularly under him, as in Fig. 57, he raises his own body up, and placing his arms round the man’s legs, he rises with him, and sets him down on some low table or eminence of the same height as his knees. This feat he sometimes performed with two men in place of one. [Illustration: _Fig. 56._] [Illustration: _Fig. 57._] 6. The last and apparently the most wonderful performance of the German is shown in Fig. 58, where he appears to raise a cannon A placed upon a scale, the four ropes of the scale being fixed to a rope or chain attached to his girdle in the manner already described. Previous to the fixing of the ropes, the cannon and scale rest upon two rollers B, C; but when all is ready, the two rollers are knocked from beneath the scale, and the cannon is sustained by the strength of his loins. [Illustration: _Fig. 58._] The German also exhibited his strength in twisting into a screw a flat piece of iron like A, Fig. 59. He first bent the iron into a right angle as at B, and then wrapping his handkerchief about its broad upper end, he held that end in his left hand, and with his right applied to the other end, twisted about the angular point, as shown at C. Lord Tullibardine succeeded in doing the same thing, and even untwisted one of the irons which the German had twisted. [Illustration: _Fig. 59._] It would lead into details by no means popular were I to give a minute explanation of the mechanical principles upon which these feats depend. A few general observations will perhaps be sufficient for ordinary readers. The feats Nos. 1, 2, and 6, depend entirely on the natural strength of the bones of the pelvis, which form a double arch, which it would require an immense force to break, by any external pressure directed to the centre of the arch; and as the legs and thighs are capable of sustaining four or five thousand pounds when they stand quite upright, the performer has no difficulty in resisting the force of two horses, or of sustaining the weight of a cannon weighing two or three thousand pounds. The feat of the anvil is certainly a very surprising one. The difficulty, however, really consists in sustaining the anvil, for when this is done, the effect of the hammering is nothing. If the anvil were a thin piece of iron, or even two or three times heavier than the hammer, the performer would be killed by a few blows; but the blows are scarcely felt when the anvil is very heavy, for the more matter the anvil has, the greater is its inertia, and it is the less liable to be struck out of its place; for when it has received by the blow the whole momentum of the hammer, its velocity will be so much less than that of the hammer, as its quantity of matter is greater. When the blow, indeed, is struck, the man feels less of the weight of the anvil than he did before, because in the reaction of the stone all the parts of it round about the hammer rise towards the blow. This property is illustrated by the well-known experiment of laying a stick with its ends upon two drinking-glasses full of water, and striking the stick downwards in the middle with an iron bar. The stick will in this case be broken without breaking the glasses or spilling the water. But if the stick is struck upwards, as if to throw it up in the air, the glasses will break if the blow be strong, and if the blow is not very quick, the water will be spilt without breaking the glasses. When the performer supports a man upon his belly as in Fig. 55, he does it by means of the strong arch formed by his backbone, and the bones of his legs and thighs. If there were room for them, he could bear three or four, or, in their stead, a great stone to be broken with one blow. A number of feats of real and extraordinary strength were exhibited, about a century ago, in London, by Thomas Topham, who was five feet ten inches high, and about thirty-one years of age. He was entirely ignorant of any of the methods for making his strength appear more surprising, and he often performed by his own natural powers what he learned had been done by others by artificial means. A distressing example of this occurred in his attempt to imitate the feat of the German Samson, by pulling against horses. Ignorant of the method which we have already described, he seated himself on the ground with his feet against two stirrups, and by the weight of his body he succeeded in pulling against a single horse; but in attempting to pull against two horses, he was lifted out of his place, and one of his knees was shattered against the stirrups, so as to deprive him of most of the strength of one of his legs. The following are the feats of real strength which Dr. Desaguliers saw him perform:-- 1. Having rubbed his fingers with coal-ashes to keep them from slipping, he rolled up a very strong and large pewter plate. 2. Having laid seven or eight short and strong pieces of tobacco-pipe on the first and third finger, he broke them by the force of his middle finger. 3. He broke the bowl of a strong tobacco-pipe placed between his first and third finger, by pressing his fingers together sideways. 4. Having thrust such another bowl under his garter, his legs being bent, he broke it to pieces by the tendons of his hams without altering the bending of his leg. 5. He lifted with his teeth, and held in a horizontal position for a considerable time, a table six feet long, with half a hundred weight hanging at the end of it. The feet of the table rested against his knees. 6. Holding in his right hand an iron kitchen poker three feet long and three inches round, he struck upon his bare left arm, between the elbow and the wrist, till he bent the poker nearly to a right angle. 7. Taking a similar poker and holding the ends of it in his hands, and the middle against the back of his neck, he brought both ends of it together before him, and he then pulled it almost straight again. This last feat was the most difficult, because the muscles which separate the arms horizontally from each other are not so strong as those which bring them together. 8. He broke a rope about two inches in circumference, which was partly wound about a cylinder four inches in diameter, having fastened the other end of it to straps that went over his shoulder. 9. Dr. Desaguliers saw him lift a rolling-stone of about 800lb. weight with his hands only, standing in a frame above it, and taking hold of a frame fastened to it. Hence Dr. Desaguliers gives the following relative view of the strengths of individuals:-- Strength of the weakest men 125lbs. Strength of very strong men 400 Strength of Topham 800 The weight of Topham was about 200. One of the most remarkable and inexplicable experiments relative to the strength of the human frame, which you have yourself seen and admired, is that in which a heavy man is raised with the greatest facility, when he is lifted up the instant that his own lungs and those of the persons who raise him are inflated with air. This experiment was, I believe, first shown in England a few years ago by Major H. who saw it performed in a large party at Venice, under the direction of an officer of the American Navy. As Major H. performed it more than once in my presence, I shall describe as nearly as possible the method which he prescribed. The heaviest person in the party lies down upon two chairs, his legs being supported by the one and his back by the other. Four persons, one at each leg and one at each shoulder, then try to raise him, and they find his dead weight to be very great, from the difficulty they experience in supporting him. When he is replaced in the chair, each of the four persons takes hold of the body as before, and the person to be lifted gives two signals by clapping his hands. At the first signal he himself and the four lifters begin to draw a long and full breath, and when the inhalation is completed, or the lungs filled, the second signal is given for raising the person from the chair. To his own surprise and that of his bearers, he rises with the greatest facility, as if he were no heavier than a feather. On several occasions I have observed that when one of the bearers performs his part ill, by making the inhalation out of time, the part of the body which he tries to raise is left as it were behind. As you have repeatedly seen this experiment, and have performed the part both of the load and of the bearer, you can testify how remarkable the effects appear to all parties, and how complete is the conviction, either that the load has been lightened, or the bearer strengthened by the prescribed process. At Venice, the experiment was performed in a much more imposing manner. The heaviest man in the party was raised and sustained upon the points of the fore-fingers of six persons. Major H. declared that the experiment would not succeed if the person lifted were placed upon a board, and the strength of the individuals applied to the board. He conceived it necessary that the bearers should communicate directly with the body to be raised. I have not had an opportunity of making any experiments relative to these curious facts; but whether the general effect is an illusion, or the result of known or of new principles, the subject merits a careful investigation. Among the remarkable exhibitions of mechanical strength and dexterity, we may enumerate that of supporting pyramids of men. This exhibition is a very ancient one. It is described, though not very clearly, by the Roman poet Claudian, and it has derived some importance in modern times, in consequence of its having been performed in various parts of Great Britain by the celebrated traveller Belzoni, before he entered upon the more estimable career of an explorer of Egyptian antiquities. The simplest form of this feat consists in placing a number of men on each other’s shoulders, so that each row consists of a man fewer till they form a pyramid terminating in a single person, upon whose head a boy is sometimes placed with his feet upwards. Among the displays of mechanical dexterity, though not grounded on any scientific principle, may be mentioned the art of walking along the ceiling of an apartment with the head downwards. This exhibition, which we have witnessed in one of the London Theatres, never failed to excite the wonder of the audience, although the movements of the inverted performer were not such as to inspire us with any high ideas of the mechanism by which they were effected. The following was probably the method by which the performer was carried along the ceiling. Two parallel grooves or openings were made in the ceiling at the same distance as the foot-tracks of a person walking on sand. These grooves were narrower than the human foot, so as to permit a rope, or chain, or strong wire, attached to the feet of the performer, to pass through the ceiling, where they were held by two or more persons above it. In this way the inverted performer might be carried along by a sliding or shuffling motion, similar to that which is adopted in walking in the dark, and in which the feet are lifted from the ground. A more regular motion, however, might be produced by a contrivance for attaching the rope or chain to the sole of the foot, at each step, and subsequently detaching it. In this way, when the performer is pulled against the ceiling by his left foot, he would lift his right foot, and having made a step with it, and planted it against the grooves, the rope would be attached to it, and when the rope was detached from the left foot, it would make a similar step, while the right foot was pulled against the ceiling. These effects might be facilitated and rendered more natural, by attaching to the body or to the feet of the performer strong wires invisible to the audience, and by using friction-wheels, if a sliding motion only is required. [Illustration: _Fig. 60._] A more scientific method of walking upon the ceiling is suggested by those beautiful pneumatic contrivances by which insects, fishes, and even some lizards are enabled to support the weight of their bodies against the force of gravity. The house-fly is well known to have the power of walking in an inverted position upon the ceilings of rooms, as well as upon the smoothest surfaces. In this case the fly does not rest upon its legs, and must therefore adhere to the ceiling, either by some glutinous matter upon its feet, or by the aid of some apparatus given it for that purpose. In examining the foot of the fly with a powerful microscope, it is found to consist of two concavities, as shown in Figs. 60 and 61, the first of which is copied from a drawing by G. Adams, published in 1746, and the second by J. C. Keller, a painter at Nuremberg, who drew it for a work published in 1766. The author of this work maintains that these concavities are only used when the fly moves horizontally, and that, when it moves perpendicularly or on the ceiling, they are turned up out of the way, and the progressive motion is effected by fixing the claws shown in the figure into the irregularities of the surface upon which the fly moves, whether it is glass, porcelain, or any other substance. Sir Everard Home, however, supposes, with great reason, that these concave surfaces are (like the leathern suckers used by children for lifting stones) employed to form a vacuum, so that the foot adheres, as it were, by suction to the ceiling, and enables the insect to support itself in an inverted position. [Illustration: _Fig. 61._] This conclusion Sir Everard has been led to draw from an examination of the foot of the Lacerta Gecko. Sir Joseph Banks had mentioned to him in the year 1815, that this lizard, which is a native of the island of Java, comes out in the evening from the roofs of the houses, and walks down the smooth hard-polished chunam walls in search of the flies which settle upon them, and which are its natural food. When Sir Joseph was at Batavia, he amused himself in catching this lizard. He stood close to the wall at some distance from the animal, and by suddenly scraping the wall with a long flattened pole, he was able to bring the animal to the ground. Having procured from Sir Joseph a very large specimen of the Gecko, which weighed 5¾ ounces avoirdupois, Sir Everard Home was enabled to ascertain the peculiar mechanism by which the feet of this animal have the power of keeping hold of a smooth hard perpendicular wall, and carry up so heavy a weight as that of its body. [Illustration: _Fig. 62._] [Illustration: _Fig. 63._] The foot of the Gecko has five toes (as shown in Fig. 62), and at the end of each of them, except the thumb, is a very sharp and highly-curved claw. On the under surface of each toe are sixteen transverse slits, leading to as many cavities or pockets, the depth of which is nearly equal to the length of the slit that forms the surface. [Illustration: _Fig. 64._] This structure is shown in Figs. 63 and 64, the former representing the under surface of one of the toes of the natural size, and the latter a toe dissected and highly magnified, to show the appearance of the cavities in its under surface, their fringed edge, the depth of the cavities, and the small muscles by which they are drawn open. The edge of the pockets or cavities is composed of rows of a beautiful fringe which are applied to the surface on which the animal walks against gravity, while the pockets themselves are pulled up by the muscles attached to them, so as to form the cavities into suckers. This structure Sir Everard Home found to bear a considerable resemblance to that portion of the head of the _Echineis Remora_, or sucking-fish, by which it attaches itself to the shark, or the bottoms of ships. This apparatus is shown in Fig. 65: it is an oval form, and is surrounded by a broad loose moveable edge, capable of applying itself closely to the surface on which it is set. It consists of two rows of cartilaginous plates connected by one edge to the surface on which they are placed, the other, on the external edge, being serrated like that in the cavities of the feet of the Gecko. The two rows are separated by a thin ligamentous partition, and the plates, being raised or depressed by the voluntary muscles, form so many vacua, by means of which the adhesion of the fish is effected. [Illustration: _Fig. 65._] These beautiful contrivances of Divine Wisdom cannot fail to arrest the attention and excite the admiration of the reader; but though there can be little doubt that they are pneumatic suckers wrought by the voluntary muscles of the animals to which they belong, yet we would recommend the further examination of them to the attention of those who have good microscopes at their command. LETTER XI. Mechanical automata of the ancients--Moving tripods--Automata of Dædalus--Wooden pigeon of Archytas--Automatic clock of Charlemagne--Automata made by Turrianus for Charles V.--Camus’s automatic carriage made for Louis XIV.--Degenne’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 conjurer--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. We have already seen that the ancients had attained some degree of perfection in the construction of automata, or pieces of mechanism which imitated the movements of man and the lower animals. The tripods, which Homer[31] mentions as having been constructed by Vulcan for the banqueting-hall of the gods, advanced of their own accord to the table, and again returned to their place. Self-moving tripods are mentioned by Aristotle; and Philostratus informs us, in his life of Apollonius, that this philosopher saw and admired similar pieces of mechanism among the sages of India. [31] Iliad, lib. xviii., 373-378. Dædalus enjoys also the reputation of having constructed machines that imitated the motions of the human body. Some of his statues are said to have moved about spontaneously; and Plato, Aristotle, and others have related that it was necessary to tie them, in order to prevent them from running away. Aristotle speaks of a wooden Venus, which moved about in consequence of quicksilver being poured into its interior; but Callistratus, the tutor of Demosthenes, states, with some probability, that the statues of Dædalus received their motion from the mechanical powers. Beckmann is of opinion that the statues of Dædalus differed only from those of the early Greeks and Egyptians in having their eyes open and their feet and hands free, and that the reclining posture of some, and the attitude of others, “as if ready to walk,” gave rise to the exaggeration that they possessed the power of locomotion. This opinion, however, cannot be maintained with any show of reason; for if we apply such a principle in one case, we must apply it in all, and the mind would be left in a state of utter scepticism respecting the inventions of ancient times. We are informed by Aulus Gellius, on the authority of Favorinus, that Archytas of Tarentum, who flourished about four hundred years before Christ, constructed a wooden pigeon that was capable of flying. Favorinus relates that, when it had once alighted, it could not again resume its flight; and Aulus Gellius adds, that it was suspended by balancing, and animated by a concealed aura, or spirit. Among the earliest pieces of modern mechanism was the curious water-clock presented to Charlemagne by the Kaliph Haroun al Raschid. In the dial-plate there were twelve small windows corresponding with the divisions of the hours. The hours were indicated by the opening of the windows, which let out little metallic balls, which struck the hour by falling upon a brazen bell. The doors continued open till twelve o’clock, when twelve little knights, mounted on horseback, came out at the same instant, and after parading round the dial, shut all the windows and returned to their apartments.[32] [32] Annales Loisiliani, anno 807. The next automata of which any distinct account has been preserved are those of the celebrated John Muller, Regiomontanus, which have been mentioned by Kircher, Baptista Porta, Gassendi, Lana, and Bishop Wilkins. This philosopher is said to have constructed an artificial eagle, which flew to meet the Emperor Maximilian when he arrived at Nuremberg on the 7th June, 1740. After soaring aloft in the air, the eagle is stated to have met the Emperor at some distance from the city, and to have returned and perched upon the town gate, where it waited his approach. When the Emperor reached the gate, the eagle stretched out its wings, and saluted him by an inclination of its body. Muller is likewise reported to have constructed an iron fly which was put in motion by wheel-work, and which flew about and leapt upon the table. At an entertainment given by this philosopher to some of his familiar friends, the fly flew from his hand, and after performing a considerable round, it returned again to the hand of its master. The Emperor Charles V., after his abdication of the throne, amused himself in his later years with automata of various kinds. The artist whom he employed was Janellus Turrianus of Cremona. It was his custom after dinner to introduce upon the table figures of armed men and horses. Some of these beat drums, others played upon flutes, while a third set attacked each other with spears. Sometimes he let fly wooden sparrows, which flew back again to their nest. He also exhibited corn-mills so extremely small that they could be concealed in a glove, yet so powerful that they could grind in a day as much corn as would supply eight men with food for a day. The next piece of mechanism of sufficient interest to merit our attention is that which was made by M. Camus, for the amusement of Louis XIV. when a child. It consisted of a small coach, which was drawn by two horses, and which contained the figure of a lady within, with a footman and page behind. When this machine was placed at the extremity of a table of the proper size, the coachman smacked his whip, and the horses instantly set off, moving their legs in a natural manner, and drawing the coach after them: when the coach reached the opposite edge of the table, it turned sharply at a right angle, and proceeded along the adjacent edge. As soon as it arrived opposite the place where the king sat, it stopped; the page descended and opened the coach-door; the lady alighted, and with a curtsey presented a petition, which she held in her hand to the king. After waiting some time she again curtsied and re-entered the carriage. The page closed the door, and having resumed his place behind, the coachman whipped his horses and drove on. The footman, who had previously alighted, ran after the carriage and jumped up behind into his former place. Not content with imitating the movements of animals, the mechanical genius of the 17th and 18th centuries ventured to perform by wheels and pinions the functions of vitality. We are informed by M. Lobat, that Gen. Degennes, a French officer who defended the colony of St. Christopher’s against the English forces, constructed a peacock which could walk about as if alive, pick up grains of corn from the ground, digest them as if they had been submitted to the action of the stomach, and afterwards discharged them in an altered form. Degennes is said to have invented various machines of great use in navigation and gunnery, and to have constructed clocks without weights or springs. The automaton of Degennes probably suggested to M. Vaucanson the idea of constructing his celebrated duck, which excited so much interest throughout Europe, and which was perhaps the most wonderful piece of mechanism that was ever made. Vaucanson’s duck exactly resembled the living animal in size and appearance. It executed accurately all its movements and gestures, it ate and drank with avidity, performed all the quick motions of the head and throat which are peculiar to the living animal, and, like it, it muddled the water which it drank with its bill. It produced also the sound of quacking in the most natural manner. In the anatomical structure of the duck, the artist exhibited the highest skill. Every bone in the real duck had its representative in the automaton, and its wings were anatomically exact. Every cavity, apophysis, and curvature was imitated, and each bone executed its proper movements. When corn was thrown down before it, the duck stretched out its neck to pick it up, it swallowed it, digested it, and discharged it in a digested condition. The process of digestion was effected by chemical solution, and not by trituration, and the food digested in the stomach was conveyed away by tubes to the place of its discharge. The automata of Vaucanson were imitated by one Du Moulin, a silversmith, who travelled with them through Germany in 1752, and who died at Moscow in 1765. Beckmann informs us that he saw several of them after the machinery had been deranged; but that the artificial duck, which he regarded as the most ingenious, was still able to eat, drink, and move. Its ribs, which were made of wire, were covered with duck’s feathers, and the motion was communicated through the feet of the duck by means of a cylinder and fine chains like that of a watch. [Illustration: _Fig. 66._] [Illustration: _Fig. 67._] Ingenious as all these machines are, they sink into insignificance when compared with the automaton chess-player, which for a long time astonished and delighted the whole of Europe. In the year 1769, M. Kempelen, a gentleman of Presburg in Hungary, constructed an automaton chess-player, the general appearance of which is shown in the annexed figures. The chess-player is a figure as large as life, clothed in a Turkish dress, sitting behind a large square chest or box, three feet and a half long, two feet deep, and two and a half high. The machine runs on castors, and is either seen on the floor when the doors of the apartment are thrown open, or is wheeled into the room previously to the commencement of the exhibition. The Turkish chess-player sits on a chair fixed to the square chest: his right arm rests on the table, and in the left he holds a pipe, which is removed during the game, as it is with this hand that he makes the moves. A chess-board, eighteen inches square, and bearing the usual number of pieces, is placed before the figure. The exhibitor then announces to the spectators his intention of showing them the mechanism of the automaton. For this purpose he unlocks the door A, Fig. 66, and exposes to view a small cupboard lined with black or dark-coloured cloth, and containing cylinders, levers, wheels, pinions, and different pieces of machinery, which _have the appearance_ of occupying the whole space. He next opens the door B, Fig. 67, at the back of the same cupboard, and holding a lighted candle at the opening, he still further displays the inclosed machinery to the spectators, placed in front of A, Fig. 66. When the candle is withdrawn, the door B is then locked; and the exhibitor proceeds to open the drawer G G, Fig. 66, in front of the chest. Out of this drawer he takes a small box of counters, a set of chess-men, and a cushion for the support of the automaton’s arm, as if this was the sole object of the drawer. The two front doors C C, of the large cupboard, Fig. 66, are then opened, and at the back-door D of the same cupboard, Fig. 67, the exhibitor applies a lighted candle, as before, for the purpose of showing its interior, which is lined with dark cloth like the other, and contains only a few pieces of machinery. The chest is now wheeled round, as in Fig. 67: the garments of the figure are lifted up, and the door E in the trunk, and another door F in the thigh, are opened, the doors B and D having been previously closed. When this exhibition of the interior of the machine is over, the chest is wheeled back into its original position on the floor. The doors A, C, C, in front, and the drawer G, G, are closed and locked, and the exhibitor, after occupying himself for some time at the back of the chest, as if he were adjusting the mechanism, removes the pipe from the hand of the figure, and winds up the machinery. The automaton is now ready to play, and when an opponent has been found among the company, the figure takes the first move. At every move made by the automaton, the wheels of the machine are heard in action; the figure moves its head, and seems to look over every part of the chess-board. When it gives check to its opponent, it shakes its head _thrice_, and only _twice_ when it checks the queen. It likewise shakes its head when a false move is made, replaces the adversary’s piece on the square from which it was taken, and takes the next move itself. In general, though not always, the automaton wins the game. During the progress of the game, the exhibitor often stands near the machine, and winds it up like a clock, after it has made ten or twelve moves. At other times he went to a corner of the room, as if it were to consult a small square box, which stood open for this purpose. The chess-playing machine, as thus described, was exhibited after its completion in Presburg, Vienna, and Paris, to thousands, and in 1783 and 1784 it was exhibited in London and different parts of England, without the secret of its movements having been discovered. Its ingenious inventor, who was a gentleman and a man of education, never pretended that the automaton itself really played the game. On the contrary, he distinctly stated, “that the machine was a _bagatelle_, which was not without merit in point of mechanism, but that the effects of it appeared so marvellous only from the boldness of the conception, and the fortunate choice of the methods adopted for promoting the illusion.” Upon considering the operations of this automaton, it must have been obvious that the game of chess was performed either by a person enclosed in the chest, or by the exhibitor himself. The first of these hypotheses was ingeniously excluded by the display of the interior of the machine, for as every part contained more or less machinery, the spectator invariably concluded that the smallest dwarf could not be accommodated within, and this idea was strengthened by the circumstance, that no person of this description could be discovered in the suite of the exhibitor. Hence the conclusion was drawn, that the exhibitor actuated the machine either by mechanical means conveyed through its feet, or by a magnet concealed in the body of the exhibitor. That mechanical communication was not formed between the exhibitor and the figure, was obvious from the fact, that no such communication was visible, and that it was not necessary to place the machine on any particular part of the floor. Hence the opinion became very prevalent that the agent was a magnet; but even this supposition was excluded, for the exhibitor allowed a strong and well-armed loadstone to be placed upon the machine during the progress of the game. Had the moving power been a magnet, the whole action of the machine would have been deranged by the approximation of a loadstone concealed in the pockets of any of the spectators. As Baron Kempelen himself had admitted that there was an illusion connected with the performance of the automaton, various persons resumed the original conjecture, that it was actuated by a person concealed in its interior, who either played the game of chess himself, or performed the moves which the exhibitor indicated by signals. A Mr. J. F. Freyhere, of Dresden, published a book on the subject in 1789, in which he endeavoured to explain, by coloured plates, how the effect was produced; and he concluded, “that a well-taught boy very thin and tall of his age (sufficiently so that he could be concealed in a drawer almost immediately under the chess-board), agitated the whole.” In another pamphlet, which had been previously published at Paris in 1785, the author not only supposed that the machine was put in motion by a dwarf, a famous chess-player; but he goes so far as to explain the manner in which he could be accommodated within the machine. The invisibility of the dwarf when the doors were opened was explained by his legs and thighs being concealed in two hollow cylinders, while the rest of his body was out of the box, and hid by the petticoats of the automaton. When the doors were shut, the clacks produced by the swivel of a ratchet-wheel permitted the dwarf to change his place, and return to the box unheard; and while the machine is wheeled about the room, the dwarf had an opportunity of shutting the trap through which he passed into the machine. The interior of the figure was next shown, and the spectators were satisfied that the box contained no living agent. Although these views were very plausible, yet they were never generally adopted; and when the automaton was exhibited in Great Britain in 1819 and 1820, by M. Maelzel, it excited as intense an interest as when it was first produced in Germany. There can be little doubt, however, that the secret has been discovered; and an anonymous writer has shown in a pamphlet, entitled “_An attempt to analyse the Automaton Chess-player of_ M. Kempelen,” that it is capable of accommodating an ordinary sized man; and he has explained in the clearest manner how the inclosed player takes all the different positions, and performs all the motions which are necessary to produce the effects actually observed. The following is the substance of his observations:--The drawer G G when closed does not extend to the back of the chest, but leaves a space O, behind it (see Figs. 74, 75, and 76), fourteen inches broad, eight inches high, and three feet eleven inches long. This space is never exposed to the view of spectators. The small cupboard seen at A is divided into two parts, by a door or screen I, Fig. 73, which is moveable upon a hinge, and is so constructed that it closes at the same instant that B is closed. The whole of the front compartment as far as I is occupied with the machinery H. The other compartment behind I is empty, and communicates with the space O behind the drawer, the floor of this division being removed. The back of the great cupboard C C is double, and the part P Q, to which the quadrants are attached, moves on a joint Q, at the upper part, and forms when raised an opening S, between the two cupboards, by carrying with it part of the partition R, which consists of cloth tightly stretched. The false back is shown closed in Fig. 74, while Fig. 75 shows the same back raised, so as to form the opening S between the chambers. When the spectator is allowed to look into the trunk of the figure by lifting up the dress, as in Fig. 75, it will be observed that a great part of the space is occupied by an inner trunk N, Figs. 75, 76, which passes off to the back in the form of an arch, and conceals from the spectators a portion of the interior. This inner trunk N opens and communicates with the chest by an aperture T, Fig. 77, about twelve inches broad and fifteen high. When the false back is raised, the two cupboards, the trunk N, and the space O behind the drawer, are all connected together. [Illustration: No. 68.] [Illustration: No. 69.] The construction of the interior being thus understood, the chess-player may be introduced into the chest through the sliding panel U, Fig. 74. He will then raise the false back of the large cupboard, and assume the position represented by the shaded figure in Figs. 68 and 69. Things being in this state, the exhibitor is ready to begin his process of deception. He first opens the door A of the small cupboard, and from the crowded and very ingenious disposition of the machinery within it, the eye is unable to penetrate far beyond the opening, and the spectator concludes, without any hesitation, that the whole of the cupboard is filled, as it appears to be, with similar machinery. This false conclusion is greatly corroborated by observing the glimmering light which plays among the wheel-work when the door B is opened, and a candle held at the opening. This mode of exhibiting the interior of the cupboard satisfies the spectator also, that no opaque body, capable of holding or concealing any of the parts of a hidden agent, is interposed between the light and the observer. The door B is now locked and the screen I closed, and as this is done at the time that the light is withdrawn, it will wholly escape observation. The door B is so constructed as to close by its own weight, but as the head of the chess-player will soon be placed very near it, the secret would be disclosed if, in turning round, the chest door should by any accident fly open. This accident is prevented by turning the key, and, lest this little circumstance should excite notice, it would probably be regarded as accidental, as the keys were immediately wanted for the other locks. As soon as the door B is locked, and the screen I closed, the secret is no longer exposed to hazard, and the exhibitor proceeds to lead the minds of the spectators still farther from the real state of things. The door A is left open to confirm the opinion that no person is concealed within, and that nothing can take place in the interior without being observed. [Illustration: _Fig. 70._] The drawer GG is now opened, apparently for the purpose of looking at the chess-men, cushion, and counters, which it contains; but the real object of it is to give time to the player to change his position, as shown in the annexed figure, and to replace the false back and partition preparatory to the opening of the great cupboard. The chess-player, as the figure shows, occupies with his body the back compartment of the small cupboard, while his legs and thighs are contained in the space O, behind the drawer GG, his body being concealed by the screen I, and his limbs by the drawer GG. The great cupboard CC is now opened, and there is so little machinery in it, that the eye instantly discovers that no person is concealed in it. To make this more certain, however, a door is opened at the back, and a lighted candle held to it, to allow the spectators to explore every corner and recess. The front doors of the great and small cupboard being left open, the chest is wheeled round to show the trunk of the figure, and the bunch of keys is allowed to remain in the door D, as the apparent carelessness of such a proceeding will help to remove any suspicion which may have been excited by the locking of the door B. When the drapery of the figure has been raised, and the doors E and F in the trunk and thigh opened, the chest is wheeled round again into its original position, and the doors E and F closed. In the mean time the player withdraws his legs from behind the drawer, as he cannot so easily do this when the drawer GG is pushed in. In all these operations, the spectator flatters himself that he has seen in succession every part of the chest, while in reality some parts have been wholly concealed from his view, and others but imperfectly shown, while at the present time nearly half of the chest is excluded from view. [Illustration: No. 71.] [Illustration: No. 72.] When the drawer G G is pushed in, and the doors A and C closed, the exhibitor adjusts the machinery at the back, in order to give time to the player to take the position shown in a front view in Fig. 71, and in profile in Fig. 72. In this position he will experience no difficulty in executing every movement made by the automaton. As his head is above the chess-board, he will see through the waistcoat of the figure, as easily as through a veil, the whole of the pieces on the board, and he can easily take up and put down a chess-man without any other mechanism than that of a string communicating with the finger of the figure. His right hand, being within the chest, may be employed to keep in motion the wheel-work for producing the noise which is heard during the moves, and to perform the other movements of the figure, such as that of moving the head, tapping on the chest, &c. A very ingenious contrivance is adopted to facilitate the introduction of the player’s left arm into the arm of the figure. To permit this, the arm of the figure requires to be drawn backwards; and for the purpose of concealing, and at the same time explaining this strained attitude, a pipe is ingeniously placed in the automaton’s hand. For this reason the pipe is not removed till all the other arrangements are completed. When every thing has been thus prepared, the pipe is taken from the figure, and the exhibitor winds up, as it were, the inclosed machinery, for the double purpose of impressing upon the company the belief that the effect is produced by machinery, and of giving a signal to the player to put in motion the head of the automaton. [Illustration: _Fig. 73._] [Illustration: _Fig. 74._] This ingenious explanation of the chess automaton is, our author states, greatly confirmed by the _regular and undeviating_ mode of disclosing the interior of the chest; and he also shows that the facts which have been observed respecting the winding up of the machine, “afford positive proof that the axis turned by the key is quite free and unconnected either with a spring or weight, or any system of machinery.” In order to make the preceding description more intelligible, I shall add the following more detailed explanation of the figures. Fig. 66 is a perspective view of the automaton seen in front with all the doors thrown open. Fig. 67 is an elevation of the automaton, as seen from behind. Fig. 68 is an elevation of the front of the chest, the shaded figure representing the inclosed player in his first position, or when the door A is opened. Fig. 69 is a side elevation, the shaded figure representing the player in the same position. Fig. 70 is a front elevation, the shaded figure showing the player in his second position, or that which he takes after the door B and screen I are closed, and the great cupboard opened. Fig. 71 is a front elevation, the shaded figure showing the player in his third position, or that in which he plays the game. Fig. 72 is a side elevation showing the figure in the same position. Fig. 73 is a horizontal section of the chest through the line WW in Fig. 71. Fig. 74 is a vertical section of the chest through the line XX in Fig. 73. [Illustration: _Fig. 75._] [Illustration: _Fig. 76._] Fig. 75 is a vertical section through the line YY Fig. 71, showing the false back closed. Fig. 76 is a similar vertical section showing the false back raised. The following letters of reference are employed in all the figures:-- A. Front door of the small cupboard. B. Back door of ditto. C C. Front doors of large cupboard.