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Chap. 14.]

Ctesibius.

121

As the earliest distinct notice

portant improvements in the mechanic arts. of cog-wheels is in the description of one of his machines, (see the clepsydra, page 547,) we may as well introduce him to the reader at this part of our subject, although we have not yet in the progress of our work, arrived at the period at which he flourished.

During the reign of Ptolemy Philadelphus over Egypt, an Egyptian barber pursued his vocation in the city of Alexandria. Like all professors of that ancient mystery, he possessed besides the inferior apparatus, the two most essential implements of all: a razor and a looking glass, or mirror, probably a metallic one. This mirror, we are informed, was suspended from the ceiling of his shop, and balanced by a weight, which moved in a concealed case in one corner of the room. Thus, when a customer had undergone the usual purifying operations, he drew down the mirror, that he might witness the improvement which the artist had wrought on his outer man; and, like Otho,

In the Speculum survey his charms. Juv. Sat. ii.

after which he returned it to its former position for the use of the next customer. It would seem that the case in which the weight moved was enclosed at the bottom, or pretty accurately made, for as the weight moved in it, and displaced the air, a certain sound was produced, either

Se

Metallic mirrors furnish one of the best proofs of skill in working the metals in the remotest times, for their antiquity extends beyond all records. In the first pages of history they are mentioned as in common use. The brazen laver of the Tabernacle, was made of the mirrors of the Israelitish women, which they carried with them out of Egypt. From some found at Thebes, as well as representations of others in the sculptures and paintings, we see at once that these looking glasses,' (as they are called in Exodus,) were similar to those of Greek and Roman ladies: viz. round or oval plates of metal, from three to six inches in diameter, and having handles of wood, stone and metal highly ornamented and of various forms, according to the taste of the wearer. Some have been found in Egypt with the lustre partially preserved. They are composed of an alloy of copper, and antimony or tin, and lead; and appear to have been carried about the person, secured to, or suspended from the girdle, as pincushions and scissors were formerly worn and are so still by some antiquated ladies. The Greeks and Romans had them also of silver and of steel. Some of the latter were found in Herculaneum. Plutarch mentions mirrors enclosed in very rich frames. Among the articles of the toilet found in Pompeii, are ear-rings, golden and common pins, and several metallic mirrors. One is round and eight inches in diameter, the other an oblong square. They had them with plane surfaces, and also convex and concave. neca says his countrywomen had them also, equal in length and breadth to a full grown person, superbly decorated with gold and silver, and precious stones. Their luxury in this article, seeins to have been excessive, for the cost of one often exceeded a moderate fortune. The dowry which the Senate gave the daughter of Scipio, according to Seneca, would not purchase in his time, a mirror for the daughter of a freedman. The Anglo Saxon dames had portable metallic mirrors, and wore them suspended from the waist. It is not a litle singular that the ancient Peruvians had them also, formed of silver, copper and its alloys, and also of obsidian stone. They had them plane, convex, and concave. Had not the art of making these mirrors been revived in the speculums of reflecting telescopes, their lustre could hardly have been appreciated; and they would probably have been considered as indifferent substitutes for the modern lookingglass. These last are supposed to have been manufactured in ancient Tyre, and of a black colored glass. Fluid lead or tin was afterwards used. It was poured on the plates while they were hot from the fire, and being suffered to cool, formed a back which reflected the image. Looking-glasses of this description were made in Venice, in the 13th century. It was not till about the 16th, that the present mode of coating the back with quicksilver and tin foil was introduced. The inventor is not known. Venus was sometimes represented with a speculum in one hand, and the astronomical symbol of the planet Venus is the figure of one. There is a chemical examination of an ancient speculum in the 17th volume of Tilloch's Phil. Mag.

Barbers flourished in the mythologic ages, for Apollo having prolonged the ears of Midas to a length resembling those of a certain animal, the latter it is said, endeavored to hide his disgrace by his hair, but found it impossible to conceal it from his barber Bronze razors were anciently common.

122

The Chain of Pots.

[Book 1 by its expulsion through some small orifice, or by its escape between the sides of the case and the weight. This sound had probably remained unnoticed like the ordinary creaking of a door, perhaps for years, until one day as the barber's son was amusing himself in his father's shop, his attention was arrested by it. This boy's subsequent reflections induced him to investigate its cause; and from this simple circumstance, he was led eventually either to invent, or greatly to improve the hydraulic organ, a musical instrument of great celebrity in ancient times. His ingenuity and industry were so conspicuous, that he was named 'The Delighter in Works of Art.' His studies in various branches of natural philosophy, were rewarded it is said, with the discovery of the pump, air-gun, fire-engine, &c. He also greatly improved the clepsydra or water-clock, in the construction of which he introduced toothed wheels, and even jeweled holes. Vitruvius, ix, 9. These ancient time-keepers, were therefore the origin of modern clocks and watches. Now this barber's son is the individual we wish to introduce to the reader, as CTESIBIUS OF ALEXANDRIA, one of the most eminent mathematicians and mechanicians of antiquity— one, whose claims upon our esteem, are not surpassed by those of any other individual, ancient or modern.

It will be perceived that the simple, the trivial sound produced by the descent of the weight in his father's shop, was to him, what the fall of the apple was to Newton, and the vibration of the lamp or chandelier in the church at Pisa, to Galileo. The circumstance presents another to the numerous proofs which might be adduced, that inquiries into the causes of the most trifling or insignificant of physical effects, are sure to lead, directly or indirectly, to important results-while to young men especially, it holds out the greatest encouragement to occupy their leisure in useful researches. It shows, that however unpropitious their circumstances may be, they may by industrious application, become distinguished in science, and may add their names to those of Ctesibius and Franklin, and many others-immortal examples of the moral grandeur of irrepressible perseverance in the midst of difficulties.

CHAPTER XV.

THE CHAIN OF POTS-Its origin-Used in Joseph's well at Cairo-Numerous in Egypt-Attempt of Belzoni to supersede it and the noria-Chain of pots of the Romans, Hindoos, Japanese, and Europeans— Described by Agricola-Spanish one-Modern one-Applications of it to other purposes than raising water-Employed as a first mover and substitute for overshot wheels-Francini's machine-Antiquity of the chain of pots-Often confounded with the noria by ancient and modern authors-Introduced into Greece by Danaus-Opinions of modern writers on its antiquity-Referred to by Solomon-Babylonian engine that raised the water of the Euphrates to supply the hanging gardens-Ropc pump-Hydraulic Belt.

THE tympanum and noria in all their modifications, have been considered as originating in the gutter or jantu, and the swape; while the machine we are now to examine is evidently derived from the primitive cord and bucket. The first improvement of the latter was the introduction of a pulley (No. 11) over which the cord was directed-the next was the addition of another vessel, so as to have one at each end of the rope, (Nos. 13 and 14) and the last and most important consisted in uniting the ends

Chap. 15.]

Egyptian Chain of Pots.

123

of the rope, and securing to it a number of vessels at equal distances through the whole of its length-and the CHAIN OF POTS, was the result. The general construction of this machine will appear from an examination of those which are employed to raise water from Joseph's well at Cairo, represented at page 46. Above the mouth of each shaft a vertical wheel is placed; over which two endless ropes pass and are suspended from it. These are kept parallel to, and at a short distance from each other, by rungs secured to them at regular intervals, so that when thus united, they form an endless ladder of ropes. The rungs are sometimes of wood, but more frequently of cord like the shrouds of a ship, and the whole is of such a length that the lowest part hangs two or three feet below the surface of the water that is to be raised. Between the rungs, earthenware vases (of the form figured No. 7) are secured by cords round the neck, and also round a knob formed on the bottom for that purpose. See A, A, in the figure. As the axis of the two wheels are at right angles to each other, two separate views of the chains are represented. In the lower pit, both ropes of one half of the chain is seen; while in the upper, the whole length of one is in view. The vases or pots are so arranged that in passing over the wheel, they fall in between the spokes which connect the two sides of the latter together, as shown in the section; and when they reach the top, their contents are discharged into a trough. [In some machines the trough passes under one rim which is made to project for that purpose; in others, it is placed below the wheel and between the chains.] There are in the upper pit, one hundred and thirty-eight pots and the distance from each other is about two feet seven inches. The contents of each are twenty cubic inches. The wheels that carry the chains are six feet and a half in diameter. They are put in motion by cog wheels (on the opposite end of their axles) working into others that are attached to the perpendicular shafts to which the blindfolded animals are yoked.

The chain of pots in Egypt is named the Sakia. Its superiority over the noria and tympanum, &c. in being adapted to raise water from every depth, has caused it to be more extensively employed for artificial irriga tion than any other Egyptian machine-hence it is to be seen in operation, all along the borders of the Nile, from its mouth up to the first cataract. In Upper Egypt, and Nubia, they are so exceedingly numerous as to occur every hundred yards; and in some cases they are not forty yards apart. Their numbers and utility have rendered them a source of revenue, for we are informed that each sakia is taxed twenty dollars per annum, while the swape is assessed at half that amount. They are also common in Abyssinia. They were noticed there by Poncet in 1698. When Sandys was in Egypt, A. D. 1611, the great number of sakias did not escape his observation: "Upon the banks all along are infinite numbers of deepe and spacious vaults into which they doe let the river, drawing up the water into higher cesterns, with wheeles set round with pitchers, and turned about by buffaloes." Travels, page 118.

An attempt was made some years ago by an enterprising European to supersede the employment of these machines in Egypt, which on account of the interesting circumstances connected with it may here be noticed. In the latter part of the last century an intelligent young man of Padua was designed by his parents for a monk, and was sent to Rome to receive an appropriate education. His inclination however led him to prefer the study of natural philosophy to that of theology, and particularly hydraulics. Upon the invasion of Italy and capture of Rome by the French, he wandered over various parts of Europe, supporting himself by publicly per

124

Roman Chain of Pots.

[Book I. forming feats of agility and strength, and by scientific exhibitions. After roving thus for fifteen years, he determined to visit Egypt, under the belief that he would make his fortune there by introducing machinery on the principle of the pump, as substitutes for the noria and chain of pots, &c. In June 1815, he landed at Alexandria, and after some delay was introduced to Mahommed Ali, (the present Pasha,) who approved of his project, and in whose gardens at Soubra, three miles from Cairo, he constructed his machine. But no sooner was it completed and put in operation than he discovered in the Turkish and Arabic cultivators an unconquerable opposition to its introduction. Indeed this result might have been anticipated and, if we are not mistaken, they were right in preferring their own simple apparatus to an elaborate machine, of the principle of whose action they were utterly ignorant. Their rejection of it was looked upon as another example of superstitious adherence to the imperfect mechanism of former ages; but under all the circumstances, it was, we believe, an evidence of the correctness of their judgment. Thus disappointed, his brightest hopes blasted, and his pecuniary resources all but exhaustedfor he received no renumeration, either for the loss of his time or his money-he, with an energy of character deserving all praise, determined to make the best of his misfortunes. He therefore turned his attention to that subject which necessarily occurs to every intelligent stranger in Egypt-its antiquities-and while the British Museum remains, and the colossal head of young Memnon is preserved, the name of BELZONI will be remembered and respected.

From the following description of the chain of pots by Vitruvius, it ap

pears that the Romans made it of more durable materials than either the ancient or modern people of Asia. "But if a place of still greater height (than could be reached by the noria) is to be supplied; on the same axis of a wheel, a double chain of iron is wound and let down to the level of the bottom; having brass buckets, each containing a congius (seven pints) hanging thereto, so that upon the turning of the wheel, the chain revolving round the axis raises the buckets to the top; which when drawn upon the axis, become inverted and pour into the reservoir the water they have brought." Book x, Cap. 9, Newton's Trans. As no reference is made to the form of the vessels, by Vitruvius, we find them represented by translators in a variety of shapes, as cylinders, cubes, truncated cones, pyramids, as well as portions of, and combinations of them all. Some are left open at the top, and both with and without projecting lips in front, by which to shoot the contents over the edge of the reservoir as they pass the wheel or drum. Others are closed, and admit and discharge the water through an orifice or short tube as represented. (No. 53.) From the separate figure of one of the vessels it

[graphic]

Chap. 15.]

Hindoo Chain of Pots.

125

will be seen that the tubes are placed at the upper corner, and consequently retain the water till the vessels ascend the drum, when it is discharged as represented. Provision should be made for the escape of air from these vessels, as they enter the water, and also for its admission on the discharge of the liquid above. The wheel or drum which carries the chain is, in this figure, solid, and cut into a hexagonal form to prevent it from slipping.

There is also in old authors a great diversity in the construction of the chains, and also in their number. Some understand by the term 'double chain,' merely a simple one doubled and its ends united; i. e. one whose length is equal to double the space through which the water is to be elevated by it. Others suppose two separate ones intended and placed parallel to each other, the vessels being connected to them as in the figure. Others again, and among them Barbaro, figure two sets of chains and pots carried by the same wheel. He has also made them pass under pulleys in the water, a useless device, except when the chains are employed in an inclined position.

The chain of pots is mentioned by most oriental travelers, although described by few. In Terry's voyage to India in 1615, speaking of the tanks and wells of the Hindoos, he observes, "they usually cover those wells with a building over head, and with oxen draw water out of them, which riseth up in many small buckets, whereof some are always going down, others continually coming up and emptying themselves in troughs or little rills, made to receive and convey the water, whither they please." p. 187. To the same machine Fryer refers, when speaking of the different modes of raising water from deep wells. It is drawn up, he says, by "with huge leathern buckets or pots around a wheel." P. 410. And again at Surat, it is drawn up "in leathern bags upon wheels." p. 104. Had not wells been mentioned in connection with these extracts from Fryer, we might have supposed it was the noria to which he alluded. Tavernier mentions it in the same way as applied to draw water from wells in Persia. p. 143. When required to raise it from rivers, they were, as in the case of the Persian wheels on the Orontes, propelled by the current when it was sufficiently rapid for the purpose. "As for the

oxen

Euphrates, (observes Tavernier,) certain it is that the great number of mills built upon it, to convey water to the neighboring grounds, have not only rendered it unnavigable, but made it very dangerous." Lucan in the 3d book of his Pharsalia alludes to this extensive diversion of the water for agricultural purposes, in his time.

But soon Euphrates' parting waves divide,
Covering, like fruitful Nile, the country wide.

These mills are probably similar to those referred to by Montanus in his account of Japan, p. 296. The city of Jonda, he observes was defended by a strong castle, which was "continually supplied with fresh water by two mills." It is a pity they were not described.

The chain of pots was used by all the celebrated nations of antiquity and it still is employed more or less over all Asia and Europe. Previous to the 16th century, it constituted the 'water works' for supplying European cities, and was often driven by windmills—as it still is in Holland. It seems to be the ne plus ultra of hydraulic engines among half civilized nations, while those only which are enlightened, have the pump. the materials of which it was made by different people of old, may be considered as emblematical of their national characters. The inhabitants of Egypt, central and southern Asia, employed light and fragile materials;

Even

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