Chapter M: P. Huber is the only modern author that appears to have been witness to (22)

These, however, are excelled by two which were lately made by English artists, and sent as a present from the East India Company to the Emperor of China. These clocks are in the form of chariots, in which are placed, in a fine attitude, a lady, leaning her right hand upon a part of the chariot, under which is a clock of curious workmanship, little larger than a shilling, that strikes and repeats, and goes eight days. Upon her finger sits a bird finely modelled, and set with diamonds and rubies, with its wings expanded in a flying posture, and it actually flutters for a considerable time on touching a diamond button below it; the body of the bird (which contains part of the wheels that in a manner give life to it) is not the bigness of the 16th part of an inch. The lady holds in her left hand a gold tube not much thicker than a large pin, on the top of which is a small round box, to which a circular ornament, set with diamonds not larger than a sixpence, is fixed, which goes round nearly three hours in a constant regular motion. Over the lady's head, supported by a small fluted pillar not bigger than a quill, are two umbrellas, under the largest of which a bell is fixed, at a considerable distance from the clock, and seems to have no connection with it; but from which a communication is secretly conveyed to a hammer that regularly strikes the hour, and repeats the same to the clock below. At the feet of the lady is a golden dog; before which, from the point of the chariot, are two birds fixed on spiral springs, the wings and feathers of which are set with stones of various colours, and appear as if flying away with the chariot, which, from another secret motion, is continued to run in a straight, circular, or any other direction; while a boy that lays hold of the chariot behind, seems also to push it forward. Above the umbrella are flowers and ornaments of precious stones; and it terminates with a flying dragon set in the same manner. The whole is of gold, most curiously executed, and embellished with rubies and pearls.

HEIDELBERG CLOCK.--At Heidelberg, in Germany, upon the town-house, was a clock with divers motions; and when the clock struck, the figure of an old man pulled off his hat, a cock crowed, and clapped his wings, soldiers fought with one another, &c.: but this curious piece of workmanship, with the castle and town, were burnt by the French, who committed at the same time the most inhuman barbarities upon the people, when they took those garrisons, in the year 1693.

STRASBURG CLOCK.--At Strasburg, there is a clock, of all others the most famous, invented by Conradus Dasipodius, in the year 1573. Before the clock stands a globe on the ground, shewing the motions of the heavenly bodies. The heavens are carried about by the first mover, in twenty-four hours; Saturn, by his proper motion, is carried about in thirty years; Jupiter in twelve, Mars in two, the Sun, Mercury, and Venus, in one year; and the Moon in one month. In the clock itself there are two tables on the right and left hand, shewing the eclipses of the Sun and Moon from the year 1573, to the year 1624. The third table in the middle is divided into three parts. In the first part, the statue of Apollo and Diana shews the course of the year, and the day thereof, being carried about in one year; the second part shews the year of our Lord, and the equinoctial days, the hours of each day, the minutes of each hour, Easter-day, and all other feasts, and the Dominical Letter. The third part has the geographical description of all Germany, and particularly of Strasburg, with the names of the inventor, and of all the workmen. In the middle frame of the clock is an astrolabe, shewing the sign in which each planet is every day, and there are the statues of the seven planets, upon a round piece of iron, lying flat; so that every day the statue of the planet that rules the day comes forth, the rest being hid within the frames, till they come out by course at their day, as the sun upon Sunday, and so for all the week. And there is also a terrestrial globe, which shews the quarter, the half hour, and the minutes. There is also the skull of a dead man, and statues of two boys, one of whom turns the hour-glass when the clock has struck, the other puts forth the rod in his hand at each stroke of the clock. Moreover, there are the statues of the Spring, Summer, Autumn, and Winter, and many observations of the moon.

In the upper part of the clock are four old men's statues, which strike the quarters of the hour; the statue of Death comes out at each quarter to strike, but is driven back by the statue of Christ, with a spear in his hand, for three-quarters; but in the fourth quarter, that of Christ goes back, and that of Death strikes the hour, with a bone in his hand, and then the chimes sound. On the top of the clock is an image of a cock, which twice in the day cries aloud, and claps his wings. Besides, this clock is decked with many rare pictures: and being on the inside of the church, carries another frame to the outside of the wall, wherein the hours of the sun, the courses of the moon, the length of the day, and such other things, are set out with great art.

CLEPSYDRA--is a water-clock, or instrument to measure time by the fall of a certain quantity of water, and is constructed on the following principles.--Suppose a cylindrical vessel, whose charge of water flows out in twelve hours, were required to be divided into parts, to be discharged each hour. 1. As the part of time is to the whole time, Twelve, so is the same time Twelve to a fourth proportional Hundred-and-forty-four. Divide the altitude of the vessel into one hundred and forty-four equal parts: here the last will fall to the last hour; the three next above, to the last part but one; the five next, to the tenth hour; lastly, the twenty-three last to the first hour. For since the times increase in the series of the natural numbers 1, 2, 3, 4, 5, &c. and the altitudes, if the numeration be in a retrograde order from the twelfth hour, increase in the series of the unequal numbers 1, 3, 5, 7, 9, &c. the altitudes computed from the twelfth hour will be as the squares of the times 1, 4, 9, 16, 25, &c. Therefore the squares of the whole time, one hundred and forty-four, comprehend all the parts of the altitude of the vessel to be emptied. But a third proportional to 1 and 12, is the square of twelve, and consequently it is the number of equal parts in which the altitude is to be distributed, according to the series of the unequal numbers, through the equal interval of hours.

There were many kinds of clepsydræ among the ancients; but they all had this in common, that the water ran generally through a narrow passage, from one vessel to another, and in the lower was a piece of cork, or light wood, which, as the vessel filled, rose up by degrees, and shewed the hour.

We shall in the next place make a few remarks on the INVENTION OF WATCHES.--The invention of spring or pocket watches belongs to the 17th century. It is true, we find mention made of a watch presented to Charles V. in the history of that prince: but this, in all probability, was no more than a kind of clock to be set on a table, some resemblance whereof we have still remaining in the ancient pieces made before the year 1670. There was also a story of a watch having been discovered in Scotland, belonging to King Robert Bruce; but this we believe has turned out altogether erroneous. The glory of this very useful invention lies between Dr. Hooke and M. Huygens; but to which of them it properly belongs, has been greatly disputed; the English ascribing it to the former, and the French, Dutch, &c. to the latter. Mr. Derham, in his Artificial Clockmaker, says, roundly, that Dr. Hooke was the inventor; and adds, that he contrived various ways of regulation. One way was, with a loadstone; another with a tender straight spring, one end whereof played backwards and forwards with the balance, so that the balance was to the spring as the bob to a pendulum, and the spring as the rod thereof. A third method was, with two balances, of which there were divers sorts; some having a spiral spring to the balance for a regulator, and others not. But the way that prevailed, and which still continues to prevail, was, with one balance, and one spring running round the upper part of the verge; though this has a disadvantage, from which those with two springs, &c. were free, since a sudden jerk, or confused shake, will alter its vibrations, and disturb its motion.

The time of these inventions was about the year 1658; as appears, among other evidences, from an inscription on one of the double-balance watches presented to King Charles II. viz. "Rob. Hooke _inven._ 1658. T. Tompion _fecit_, 1675." The invention presently got into reputation, both at home and abroad: and two of them were sent for by the dauphin of France. Soon after this, M. Huygens' watch with a spiral spring got abroad, and made a great noise in England, as if the longitude could be found by it. It is certain, however, that his invention was later than the year 1673, when his book "_De Horol. Oscillat._" was published; wherein he has not one word of this, though he has of several other contrivances in the same way.

One of these the Lord Brouncker sent for out of France, where M. Huygens had got a patent for them. This watch agreed with Dr. Hooke's, in the application of the spring to the balance; only M. Huygens' had a long spiral spring, and the pulses and beats were much slower. The balance, instead of turning quite round, as Dr. Hooke's, turns several rounds every vibration.

Mr. Derham suggests, that he has reason to think M. Huygens' fancy was first set to work by some intelligence he might have of Dr. Hooke's invention from Mr. Oldensworth, or some other of his correspondents in England; and this, notwithstanding Mr. Oldensworth's attempt to vindicate himself in the Philosophical Transactions, appears to be the truth. Huygens invented divers other kinds of watches, some of them without any string or chain at all; which he called particularly, pendulum watches.

CHAP. LXXIII.

CURIOSITIES RESPECTING THE ARTS.--(_Continued._)

_Telegraph--Spectacle of a Sea Fight at Rome--Wooden Eagle; and Iron
Fly--Whitehead's Ship--Scaliot's Lock, &c.--Praxiteles' Venus--Weaving
Engine--Hydraulic Birds--Herschell's Grand Telescope--Boverick's
Curiosities--Bunzlau Curiosities--Artificial Flying._

TELEGRAPH.--This is a word derived from the Greek, and which is very properly given to an instrument, by means of which information may be almost instantaneously conveyed to a considerable distance. The telegraph, though it has been generally known and used by the moderns only for a few years, is by no means a modern invention. There is reason to believe, that amongst the Greeks there was some sort of telegraph in use. The burning of Troy was certainly known in Greece very soon after it happened, and before any person had returned from thence. Now that was altogether so tedious a piece of business, that conjecture never could have supplied the place of information. A Greek play begins with a scene, in which a watchman descends from the top of a tower in Greece, and gives the information that Troy was taken. "I have been looking out these ten years (says he) to see when that would happen, and this night it is done." Of the antiquity of a mode of conveying intelligence quickly to a great distance, this is certainly a proof. The Chinese, when they send couriers on the great canal, or when any great man travels there, make signals by fire, from one day's journey to another, to have every thing prepared; and most of the barbarous nations used formerly to give the alarm of war by fires lighted on the hills, or rising grounds.

It does not appear that the moderns had thought of such a machine as a telegraph, till the year 1663, when the Marquis of Worcester, in his "Century of Inventions," affirmed, that he had discovered "a method by which, at a window, as far as eye can discover black from white, a man may hold discourse with his correspondent, without noise made, or notice taken, being, according to occasion given, or means afforded, _ex re nata_, and no need of provision beforehand; though much better if foreseen, and course taken by mutual consent of parties." This could be done only by means of a telegraph, which, in the next sentence, is declared to have been rendered so perfect, that by means of it the correspondence could be carried on "by night as well as by day, though as dark as pitch is black."

About forty years afterwards, M. Amontons proposed a new telegraph. His method was this:--Let there be people placed in several stations, at such a distance from one another, that, by the help of a telescope, a man in one station may see a signal made in the next before him; he must immediately make the same signal, that it may be seen by persons in the station next after him, who are to communicate it to those in the following station, and so on. These signals may be as letters of the alphabet, or as a cipher, understood only by the two persons who are in the distant places, and not by those who make the signals. The person in the second station making the signal to the person in the third, the very moment he sees it in the first; the news may be carried to the greatest distance in as little time as is necessary to make the signals in the first station. The distance of the several stations, which must be as few as possible, is measured by the reach of a telescope. Amontons tried this method in a small tract of land, before several persons of the highest rank at the court of France. It was not, however, till the French revolution, that the telegraph was applied to useful purposes.

Whether M. Chappe, who is said to have invented the telegraph first used by the French about the end of 1793, knew any thing of Amonton's invention or not, it is impossible to say; but his telegraph was constructed on principles nearly similar. The manner of using this telegraph was as follows:--At the first station, which was on the roof of the palace of Louvre, at Paris, M. Chappe, the inventor, received in writing from the Committee of Public Welfare, the words to be sent to Lisle, near which the French army at that time was. An upright post was erected on the Louvre, at the top of which were two transverse arms, moveable in all directions by a single piece of mechanism, and with inconceivable rapidity. He invented a number of positions for these arms, which stood as signs for the letters of the alphabet; and these, for the greater celerity and simplicity, he reduced in number as much as possible. The grammarian will easily conceive that sixteen signs may amply supply all the letters of the alphabet, since some letters may be omitted, not only without detriment, but with advantage. These signs, as they were arbitrary, could be changed every week; so that the sign of B for one day, might be the sign of M the next; and it was only necessary that the persons at the extremities should know the key. The intermediate operators were only instructed generally in these sixteen signals; which were so distinct, so marked, so different the one from the other, that they were remembered with the greatest ease.

The construction of the machine was such, that each signal was uniformly given in precisely the same manner at all times: it did not depend on the operator's manual skill; and the position of the arm could never, for any one signal, be a degree higher or a degree lower, its movement being regulated mechanically. M. Chappe having received, at the Louvre, the sentence to be conveyed, gave a known signal to the second station (which was Mont Martre) to prepare. At each station there was a watch-tower, where telescopes were fixed, and the person on watch gave the signal of preparation which he had received, and this communicated successively through all the line, which brought them all into a state of readiness. The person at Mont Martre then received, letter by letter, the sentence from the Louvre, which he repeated with his own machine; and this was again repeated from the next height, with inconceivable rapidity, to the final station at Lisle.

Various experiments were in consequence tried upon telegraphs in this country; and one was soon after set up by government, in a chain of stations from the admiralty-office to the sea-coast. It consists of six octagon boards, each of which is poised upon an axis in a frame, in such a manner that it can be either placed vertically, so as to appear with its full size to the observer at the nearest station, or it becomes invisible to him by being placed horizontally, or with only the narrow edge exposed. These six boards make thirty-six changes, by the most plain and simple mode of working; and they will make many more, if more were necessary.

We submit to the reader the following account of a SPECTACLE OF A SEA FIGHT AT ROME.--Augustus, to divert his mind from fixing on his domestic misfortunes, exhibited the most magnificent and expensive shows that had ever been seen at Rome. Chariot-races in the circus, representations on the stage, combats by gladiators, &c. were now become common. Augustus, therefore, the better to divert both himself and the people, revived these sports, which had been for a considerable time laid aside, on account of the extraordinary charges that attended them. He caused a canal to be dug, eighteen hundred paces in length, and two hundred in breadth, conveying into it the Flaminian waters, and building scaffolds quite round it, capable of holding a prodigious multitude of spectators. And indeed the concourse of people was so great, that the emperor was obliged to place guards in all quarters of the city, lest the thieves should lay hold of that opportunity to plunder the empty and abandoned houses. Augustus had frequently entertained the people with fights of lions, tigers, elephants, rhinoceroses, &c. but now the new canal appeared all on a sudden covered with crocodiles, of which thirty-six were killed by Egyptians, brought from the banks of the Nile for that purpose. The multitude were highly delighted by this sight, which was quite new; but the sea-fight which ensued, afforded them still greater diversion: for, at the opposite ends of the lake, or canal, two fleets appeared, the galleys of one being built after the Greek, and those of the other after the Persian manner. Both fleets engaged; and, as they fought in good earnest, most of the combatants being persons sentenced to death, the battle proved very bloody.

A WOODEN EAGLE, AND AN IRON FLY.--Petrus Ramus tells us of a Wooden Eagle and an Iron Fly, made by Regiomontanus, a famous mathematician at Nuremberg: whereof the first flew forth out of the city, aloft in the air, met the Emperor Maximilian a good way off, coming towards it; and, having saluted him, returned again, waiting on him at the city gates. The second, at a feast, whereto the Emperor had invited his familiar friends, flew forth from his hand, and, taking a round, returned thither again, to the great astonishment of the beholders: both which, the excellent pen of the noble Du Bartas has expressed in the following lines:

Why should I not that Wooden Eagle mention,
A learned German's late admir'd invention,
Which, mounting from his fist that fram'd her,
Flew far to meet the German Emperor?
And, having met him, with her nimble train
And pliant wings turning about again,
Follow'd him close unto the castle gate
Of Nuremberg; whom all their shows of state,
Streets hung with arras, arches curious built,
Grey-headed senate, and youth's gallantries,
Grac'd not so much as only this device.

He goes on, and thus describes the Fly:

Once, as this artist, more with mirth than meat;
Feasted some friends whom he esteemed great,
Forth from his hand an Iron Fly flew out;
Which having flown a perfect round about,
With weary wings returned to his master,
And as judicious on his arm he plac'd her.
Oh! wit divine, that in the narrow womb
Of a small Fly could find sufficient room
For all those springs, wheels, counterpoise, and chains,
Which stood instead of life, and blood, and veins.

WHITEHEAD'S SHIP.--George Whitehead, an Englishman, made a ship, with all her tackling, to move itself on a table, with rowers plying the oars, a woman playing on the lute, and a little whelp crying on the deck,--says Scottus, in his Itinerary.

SCALIOT'S LOCK, &c.--In the twentieth year of Queen Elizabeth, Mark Scaliot, a blacksmith, made a lock, consisting of eleven pieces of iron, steel, and brass, all which, together with a pipe-key to it, weighed but one grain of gold: he made also a chain of gold, consisting of forty-three links, whereunto having fastened the lock and key before mentioned, he put the chain about a flea's neck, which drew them all with ease. All these together, lock and key, chain and flea, being weighed, the weight of them was but one grain and a half.

PRAXITELES' VENUS.--Praxiteles, who was an ingenious worker in imagery, made a statue of Venus for the Cnidians, so much resembling life, that a certain young man became enamoured of it to such a degree, that the excess of his love deprived him of his senses. This piece of art was so eagerly coveted by king Nicomedes, that, though the Cnidians owed him an immense sum of money, he offered to take the statue in full satisfaction for his debt; but was refused.

The next subject is a curious WEAVING ENGINE.--At Dantzic in Poland, there was set up a rare invention for weaving four or five webs at a time, without any human help. It was an engine that moved of itself, and would work night and day. This invention was suppressed, because it would have ruined the poor people of the town; and the artificer was secretly destroyed, as Lancelotti, the Italian abbot, relates from the mouth of M. Muller, a Pole, who had seen the device.

HYDRAULIC BIRDS.--At Tibur, in Tivoli, near Rome, in the gardens of Hippolitus d'Este, Cardinal of Ferrara, there are the representations of sundry birds sitting on the tops of trees, which, by hydraulic art, and secret conveyances of water through the trunks and branches of the trees, are made to sing and clap their wings; but at the sudden appearance of an owl out of a bush of the same artifice, they immediately become all mute and silent. It was the work of Claudius Gallus, as Possivenus informs us.

HERSCHELL'S GRAND TELESCOPE.--The tube of this telescope is thirty-nine feet four inches in length, and four feet ten inches in diameter, every part being made of iron. It stands in the open air, appears to be considerably elevated, and is encircled with a complicated scaffolding, by which its steadiness is secured. The concave face of its speculum is _forty-eight inches_ of polished surface in diameter, and it weighs nearly _two thousand one hundred and eighteen pounds_! With proper eye-glasses it magnifies above _six thousand times_: it is the largest instrument, and has the greatest magnifying power, of any that has been made. By its aid, Dr. Herschell has been able to observe the lightning in the atmosphere of the moon, and has found out several celestial bodies, unknown to preceding astronomers. The whole was finished on August the 28th, 1789, on which day the _sixth_ satellite of Saturn was discovered. The observer, suspended at the end of the instrument, with his back towards the object he views, looks down the tube, and sees the image reflected from the mirror; whilst a man below turns gently round the instrument, to accord with the apparent rotatory motion of the heavens, thus preserving the image of the object on the mirror with stability.

BOVERICK'S CURIOSITIES.--Mr. Baker, in his Treatise on the Microscope, says, "I myself have seen, near Durham Yard, in the Strand, and have examined with my microscope, a chaise, (made by one Mr. Boverick, a watch-maker,) having four wheels, with all the proper apparatus belonging to them, turning readily on their axles, together with a man sitting in the chaise, all formed of ivory, and drawn along by a flea, without any seeming difficulty. I weighed it with the greatest care I was able; and found the chaise, man, and flea, were barely equal to a single grain. I weighed also, at the same time and place, a brass chain made by the same hand, about two inches long, containing two hundred links, with a hook at one end, and a padlock and key at the other; and found it less than the third part of a grain. I have seen (made by the same artist) a quadrille table with a drawer in it, an eating-table, a sideboard table, a looking-glass, twelve chairs, with skeleton backs, two dozen of plates, six dishes, a dozen knives, and as many forks, twelve spoons, two salts, a frame and castors, together with a gentleman, lady, and footman, all contained in a cherry-stone, and not filling much more than half of it."

BUNZLAU CURIOSITIES.--Mr. Adams, in his Letters on Silesia, gives the following account of two ingenious mechanics he met with at Bunzlau. Their names were Jacob, and Huttig; the one was a carpenter, the other a weaver, and they were next-door neighbours to each other. "The first (says Mr. Adams) has made a machine, in which, by the means of certain clock-work, a number of puppets, about six inches high, are made to move upon a kind of stage, so as to represent in several successive scenes the passion of Jesus Christ. The first exhibits him in the garden at prayer, while the three apostles are sleeping at a distance. In the last, he is shewn dead in the sepulchre, guarded by two Roman soldiers. The intervening scenes represent the treachery of Judas, the examination of Jesus before Caiaphas, the dialogue between Pilate and the Jews concerning him, the denial of Peter, the scourging, and the crucifixion. It is all accompanied by a mournful dirge of music; and the maker, by way of explanation, repeats the passages of Scripture which relate the events he has undertaken to shew. I never saw a stronger proof of the strength of the impression of objects, which are brought immediately home to the senses. I have heard and read more than one eloquent sermon upon the passion; but I confess, none of their most laboured efforts at the pathetic ever touched my heart with one-half the force of this puppet-show. The traitor's kiss, the blow struck by the high-priest's servant, the scourging, the nailing to the cross, the sponge of vinegar, every indignity offered, and every pain inflicted, occasioned a sensation, when thus made perceptible to the eye, which I had never felt at mere description.

"Hultig, the weaver, with an equal, or superior mechanical genius, has applied it in a different manner, and devoted it to geographical, astronomical, and historical pursuits. In the intervals of his leisure from the common weaver's work, which affords him subsistence, he has become a very learned man. The walls of his rooms are covered with maps and drawings of his own, representing, here the course of the Oder, with all the towns and villages through which it runs; there, the mountains of Switzerland, and those of Silesia, over both of which he has travelled in person. In one room he has two very large tables, one raised above the other: on one of them he has ranged all the towns and remarkable places of Germany; and on the other, of all Europe: they are placed according to their respective geographical bearings. The names of the towns are written on a small square piece of paper, and fixed in a slit on the top of a peg, which is stuck into the table. The remarkable mountains are shewn by some pyramidical black stones; and little white pyramids are stationed at all the spots which have been distinguished by any great battle, or other remarkable incident. The man himself, in explaining his work, shews abundance of learning, relative to the ancient names of places, and the former inhabitants of the countries to which he points; and amused us with anecdotes of various kinds, connected with the lands he has marked out.

"Thus, in shewing us the Alps, he pointed to the very spot over which the French army of reserve so lately passed, and where Buonaparte so fortunately escaped being taken by an Austrian officer; and then he gave us a short comment of his own, upon the character and extraordinary good fortune of the First Consul. In a second room he has a large machine, representing the Copernican system of the universe: it is made in such a manner, that the whole firmament of fixed stars moves round our solar system once in every twenty-four hours, and thus always exhibits the stars, in the exact position, relative to our earth, in which they really stand. Internally, he has stationed all the planets which belong to our system, with their several satellites, and all the comets that have been observed during the last three centuries. In a third room he has another machine, exhibiting in different parts the various phases of the moon, and those of Jupiter's satellites, the apparent motion of the sun round the earth, and the real motion of the earth round the sun.

"In his garret he has another work, upon which he is yet occupied, and which, being his last labour, seems to be that in which he takes the most delight. Upon a very large table, similar to that in the first room, he has inlaid a number of thin plates of wood, formed so as to represent a projection of the earth under Mercator's plan. All the intervals between the plates of wood designate that portion of the world which is covered with water. He has used a number of very small ropes of two colours, drawn over the surface in such a manner as to describe the tracks of all the celebrated circumnavigators of the globe. The colours of the ropes distinguish the several voyages which claim especial pre-eminence above the rest. To Columbus, Anson, and Cook, he has shewn a special honour by three little models of ships bearing their names, which are placed upon the surface of his ocean, in some spot of their respective courses. The names of all the other voyagers, and the times at which their voyages were performed, are marked by papers fixed at the points of their departure. Such is the imperfect description I can give you, from a short view of the labours of this really curious man. He must be nearly, or quite seventy years old, and has all his lifetime been of an infirm constitution. But this taste for the sciences, he told us, was hereditary in his family, and had been common to them all, from his great-grandfather down to himself. His dress and appearance were those of a common weaver: but his expressive countenance, at once full of enthusiastic fire and of amiable good-nature, was a model, upon which Lavater might expatiate with exultation. The honest and ingenious weaver, on our taking leave, made us smile by exclaiming, that now, if he could but have a traveller from Africa come to see his works, he could boast of having had visitors from all the four quarters of the globe."

ARTIFICIAL FLYING.--The art of flying has been attempted by several persons in all ages. The Leucadians, out of superstition, are reported to have had a custom of precipitating a man from a high cliff into the sea, first fixing feathers, variously expanded, round his body, in order to break his fall. Friar Bacon, who lived near five hundred years ago, not only affirms the art of flying possible, but assures us, that he himself knew how to make an engine, wherein a man, sitting, might be able to cenvey himself through the air, like a bird; and further adds, that there was one who had then tried it with success: but this method, which consisted of a couple of large thin hollow copper globes, exhausted of the air, and sustaining a person who sat thereon, Dr. Hooke shews to be impracticable. The philosophers of King Charles the Second's reign were mightily busied about this art. Bishop Wilkins was so confident of success in it, that he says, he does not question but, in future ages, it will be as usual to hear a man call for his wings, when he is going a journey, as it is now to call for his boots.

The art of flying has in some measure been brought to bear in the construction and use of balloons.

CHAP. LXXIV.

CURIOSITIES RESPECTING THE ARTS.--(_Concluded._)

_Burning Glasses--Ductility of Glass--Remarkable Ductility and
Extensibility of Gold--Pin Making--Needles--Shoes--The Great Bell of
Moscow._

BURNING GLASSES.--We have some extraordinary instances and surprising accounts of prodigious effects of burning-glasses. Those made of reflecting mirrors are more powerful than those made with lenses, because the rays from a mirror are reflected all to one point nearly; whereas by a lens, they are refracted to different points, and are therefore not so dense or ardent. The whiter also the metal or substance is, of which the mirror is made, the stronger will be the effect.

The most remarkable burning-glasses, or rather mirrors, among the ancients, were those of Archimedes and Proclus; by the first of which the Roman ships, besieging Syracuse, (according to the testimony of several writers,) and by the other, the navy of Vitalian besieging Byzantium, were reduced to ashes. Among the moderns, the burning mirrors of greatest eminence, are those of Vilette, and Tschirnhausen, and the new complex one of M. de Buffon.

That of M. de Vilette was three feet eleven inches in diameter, and its focal distance was three feet two inches. Its substance is a composition of tin, copper, and tin glass. Some of its effects, as found by Dr. Harris and Dr. Desaguliers, are, that a silver sixpence melted in seven seconds and a half; a king George's halfpenny melted in sixteen seconds, and ran in thirty-four seconds; tin melted in three seconds; and a diamond weighing four grains, lost seven-eighths of its weight. That of M. de Buffon is a polyhedron, six feet broad, and as many high, consisting of one hundred and sixty-eight small mirrors, or flat pieces of looking-glass, each six inches square; by means of which, with the faint rays of the sun in the month of March, he set on fire boards of beechwood at one hundred and fifty feet distance. Besides, his machine has the conveniency of burning downwards, or horizontally, at pleasure; each speculum being moveable, so as, by the means of three screws, to be set to a proper inclination for directing the rays towards any given point; and it turns either in its greater focus, or in any nearer interval, which our common burning-glasses cannot do, their focus being fixed and determined. M. de Buffon, at another time, burnt wood at the distance of two hundred feet. He also melted tin and lead at the distance of above one hundred and twenty feet, and silver at fifty.

Mr. Parker, of Fleet-street, London, was induced, at an expense of upwards of £700, to contrive, and at length to complete, a large transparent lens, that would serve the purpose of fusing and vitrifying such substances as resist the fires of ordinary furnaces, and more especially of applying heat in vacuo, and in other circumstances in which it cannot be applied by any other means. After directing his attention for several years to this object, and performing a great variety of experiments in the prosecution of it, he at last succeeded in the construction of a lens, of flint-glass, three feet in diameter, which, when fixed in its frame, exposes a surface two feet eight inches and a half in the clear, without any other material imperfection, except a disfigurement of one of the edges by a piece of the scoria of the mould, which unfortunately found its way into its substance. This lens was double-convex, both sides of which were a portion of a sphere of eighteen feet radius. It is difficult to form an accurate estimate of the burning power of this lens; inasmuch as it is next to impossible to discover what should be deducted for the loss of power, in consequence of the impediments that the glass of which it was made must occasion, as well as the four reflections, and two more by way of diminution; but we will endeavour to appreciate it, after a full allowance for these deductions, which must necessarily result from every means of concentrating the solar rays, and must be considered as the friction of an engine, of which nature they really partake.

The solar rays received on a circular surface of two feet eight inches and a half, when concentrated within the diameter of an inch, will be 105,626 times its intensity, or this number of times greater than the heat of the sun as it is experienced on the surface of the earth. We will suppose, that as the heat of the air, in ordinary summer weather, is 65 degrees, and in sultry weather is 75 degrees, the average of which is 70 degrees, and that we take this as the average effect, the accumulated power of the lens, on the supposition of an uniform heat over the whole surface of the focus, will be equal to 73,938 degrees. It must be recollected, by those who have an opportunity of examining the effects of this lens, that the external part of the focal light was less intense than that part which was near the centre of it; or rather, that the effect was very much accumulated in the centre; but as it is possible that the refraction of the light and of the caloric fluid may not take place in the same angles, we think it safest to consider it as of uniform effect, and alter deducting one fourth part thereof as a compensation, there remains 5545 as the expression of its power. As the application of the second lens reduced the diameter of the focus to half an inch, the effect, without allowing for the reduction of its power, would be equal to 221,816 degrees; but deducting one-fourth for the second transmission, there remains 166,362 degrees, as the expression of its power.

Mr. Parker further informs us, that a diamond, weighing ten grains, exposed to this lens for thirty minutes, was reduced to six grains; during which operation it opened and foliated like the leaves of a flower, which emitted whitish fumes, and when closed again, bore a polish, and retained its form. Gold remained in its metallic state without apparent diminution, notwithstanding an exposure at intervals of many hours: but what is remarkable, the rest, or cupel, which was composed of bone-ash, was tinctured with a beautiful pink colour.

The experiments on platina evince that the specimens were in different states of approach to a complete metallic form; several of them threw off their parts in sparks, which in most instances were metallic. Copper, after three minutes' exposure, was not found to have lost in weight.

What is remarkable with regard to experiments on iron, is, that the lower part, i. e. that part in contact with the charcoal, was first melted, when that part which was exposed to the focus remained unfused; an evidence of the effect of flux on this metal.

Several of the semi-crystalline substances, exposed to the focal heat, exhibited symptoms of fusion; such as the agate, oriental flint, cornelian, and jasper: but as the probability is, that these substances were not capable of complete vitrification, it is enough that they were rendered externally of a glassy form. Garnet completely fused on black lead in 120 seconds, lost a quarter of a grain, became darker in colour, and was attracted by the magnet. Ten cut garnets taken from a bracelet began to run the one into the other in a few seconds, and at last formed into one globular garnet. The clay used by Mr. Wedgwood to make his pyrometric test, run in a few seconds into a white enamel. Seven other kinds of clay, sent by Mr. Wedgwood, were all vitrified. Several experiments were made on limestone, some of which were vitrified, but all of which were agglutinated; it is, however, suspected that some extraneous substance must have been intermixed. A globule produced from one of the specimens, on being put into the mouth, flew into a thousand pieces, occasioned, it is presumed, by the moisture.

A subscription was proposed for raising the sum of seven hundred guineas, towards indemnifying the charges of the inventor, and retaining the very curious and useful machine above described in our own country; but from the failure or the subscription, and some other concurring circumstances, Mr. Parker was induced to dispose of it to Capt. Mackintosh, who accompanied Lord Macartney in the embassy to China: and it was left, much to the regret of philosophers in Europe, at Pekin; where it remains in the hands of persons, who most probably know neither its value nor use.

DUCTILITY OF GLASS.--We all know, that when glass is well penetrated with the heat of the fire, the workmen can figure and manage it like soft wax; but, what is most remarkable, it may be drawn, or spun out, into threads exceedingly long and fine. Our ordinary spinners do not form their threads of silk, flax, or the like, with half the ease and expedition the glass-spinners do threads of this brittle matter. We have some of them used in plumes for children's heads, and divers other works, much finer than any hair, and which bend and wave, like hair, with every wind. Nothing is more simple and easy than the method of making them. There are two workmen employed: the first holds one end of a piece of glass over the flame of a lamp; and when the heat has softened it, a second operator applies a glass hook to the metal thus in fusion, and, withdrawing the hook again, it brings with it a thread of glass, which still adheres to the mass; then, fitting his hook on the circumference of a wheel about two feet and a half in diameter, he turns the wheel as fast as he pleases, which, drawing out the thread, winds it on its run, till, after a certain number of revolutions, it is covered with a skein of glass-thread. The mass in fusion over the lamp diminishes insensibly, being wound out like a clue of silk upon the wheel; and the parts cooling as they recede from the flame, become more coherent to those next to them, and this by many degrees: the parts nearest the fire are always the least coherent, and, of consequence, must give way to the effort the rest make to draw them towards the wheel. The circumference of these threads is usually a flat oval, being three or four times as broad as thick: some of them seem scarcely bigger than the thread of a silkworm, and are surprisingly flexible. If the two ends of such threads are knotted together, they may be drawn and bent, till the aperture, or space in the middle of the knot, does not exceed one-fourth of a line, or one forty-eighth of an inch in diameter. Hence M. Reaumur maintains, that the flexibility of glass increases in proportion to the fineness of the threads; and that, probably, had we but the art of drawing threads as fine as a spider's web, we might weave stuffs and cloths of them for wear. Accordingly, he made some experiments this way; and found that he could make threads fine enough, viz. as fine, in his judgment, as spider's thread, but not long enough for the purposes of any manufacture.

REMARKABLE DUCTILITY AND EXTENSIBILITY OF GOLD.--Gold is the most ductile, as well as the most malleable, of all metals. According to Cronstedt, one grain of it may be stretched out so as to cover 98 Swedish ells, equal to 63.66 English yards of silver wire; but Wallerius asserts, that a grain may be stretched out in such a manner, as to cover 500 ells of wire. At any rate, the extension is prodigious; for, according to the least of the calculations, the millionth part of a grain of gold may be made visible to the naked eye. Nor is its malleability inferior to its ductility. Boyle, quoted by Apligny, in his treatise on Colours, says, that one grain and a half of gold may be beaten into 50 leaves of an inch square, which, if intersected by parallel lines drawn at right angles to each other, and distant only the hundredth part of an inch from each other, will produce twenty-five millions of little squares, each very easily discernible by the naked eye. Mr. Magellan tells us, that its surface may be extended by the hammer 159,092 times. "I am informed, (says he) by an intelligent goldbeater in England, that the finest gold leaf is that made in new skins, and must have an alloy of three grains of copper to the ounce of pure gold, or else it would be too soft to pass over the irregularities of the skins. He affirms, that 80 books, or 2000 leaves of gold, each leaf containing 10.89 square inches, weigh less than 384 grains. Each book, therefore, of 25 leaves, or 272.25 inches, weighs less than 4.8 grains; so that each grain of the metal will produce about 57 square inches of gold leaf." From further calculation it appears, that the thickness of these leaves is less than the 282,000th part of an inch; and that 16 ounces of gold would be sufficient to gild a silver wire, equal in length to the whole circumference of the globe we inhabit!

PIN-MAKING.--Though pins are apparently simple, their manufacture is not a little curious and complex. When the brass wire, of which the pins are formed, is first received at the manufactory, it is generally too thick for the purpose of being cut into pins. The first operation, therefore, is that of winding it off from one wheel to another with great velocity, and causing it to pass between the two, through a circle in a piece of iron of smaller diameter. The wire being thus reduced to its proper dimensions, is straightened by drawing it between iron pins, fixed in a board in a zigzag manner, but so as to leave a straight line between them: afterwards it is cut into lengths of three or four yards, and then into smaller ones, every length being sufficient to make six pins. Each end of these is ground to a point, which was performed, (where these observations were made,) by boys, who sat each with two small grinding-stones before him, turned by a wheel. Taking up a handful, he applied the ends to the coarsest of the two stones, being careful at the same time to keep each piece moving round between his fingers, so that the points may not become flat: he then gives them a smoother and sharper point by applying them to the other stone, and by that means a lad of twelve or fourteen years of age, is able to point about sixteen thousand pins in an hour. When the wire is thus pointed, a pin is taken off at each end, and this is repeated till it is cut into six pieces. The next operation is, that of forming the heads, or, as they term it, head-spinning, which is done by means of a spinning-wheel, one piece of wire being thus with astonishing rapidity wound round another, and the interior one being drawn out, leaves a hollow tube between the circumvolutions: it is then cut with shears, every two circumvolutions, or turns of the wire, forming one head; these are softened by throwing them into iron pans, and placing them in a furnace till they are red hot. As soon as they are cold, they are distributed to children, who sit with hammers and anvils before them, and catching one at the extremity, they apply them immediately to the anvil and hammer, and by a motion or two of the foot, the top and the head are fixed together in much less time than it can be described, and with a dexterity only to be acquired by practice. The pin is now finished as to its form, but still it is merely brass; it is therefore thrown into a copper containing a solution of tin and the lees of wine. Here it remains for some time, and, when taken out, assumes a white, though dull appearance: in order therefore to give it a polish, it is put into a tub containing a quantity of bran, which is set in motion by turning a shaft that runs through its centre, and thus, by means of friction, it becomes perfectly bright. The pin being complete, nothing remains but to separate it from the bran, which is perfectly similar to the winnowing of corn, the bran flying off, and leaving the pin behind it for immediate sale.

We must not forget to present to the reader some curious particulars respecting the manufacture of NEEDLES.--Needles make a very considerable article in commerce, though there is scarcely any commodity cheaper, the consumption of them being almost incredible. The sizes are from No. 1, the largest, to No. 25, the smallest. In the manufacture of needles, German and Hungarian steel are of most repute.

In the making of them, the first thing is, to pass the steel through a coal fire, and under a hammer, to bring it out of its square figure into a cylindrical one. This done, it is drawn through a large hole of a wire-drawing iron, and returned into the fire, and drawn through a second hole of the iron, smaller than the first; and thus successively from hole to hole, till it has acquired the degree of fineness required for that species of needles; observing, every time it is to be drawn, that it be greased over with lard, to render it more manageable. The steel, thus reduced to a fine wire, is cut in pieces of the length of the needles intended. These pieces are flatted at one end on the anvil, by force of a puncheon of well-tempered steel, and laid on a leaden block to bring out, with another puncheon, the little piece of steel remaining in the eye. The corners are then filed off the square of the heads, and a little cavity filed on each side of the flat of the head; this done, the point is formed with a file, and the whole filed over: they are then laid to heat red-hot on a long narrow iron, crooked at one end, in a charcoal fire; and when taken out thence, are thrown into a bason of cold water to harden. On this operation a good deal depends; too much heat burns them, and too little leaves them soft; the medium is learned by experience. When they are thus hardened, they are laid in an iron shovel on a fire more or less brisk in proportion to the thickness of the needles; taking care to move them from time to time. This serves to temper them, and take off their brittleness; great care here too must be taken of the degree of heat. They are then straightened one after another with the hammer, the coldness of the water used in hardening them having twisted the greatest part of them.