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stant liability to derangement, as much so as to its rotary movement. Nor is it likely that they were much superior at any time in Judea, for the Jews never cultivated the arts to any extent. The mechanics among them when they left Egypt were probably more numerous and expert than during any subsequent period of their history. In the eleventh century B. C. when Saul began to reign, there was not a blacksmith in the land, or one that could forge iron; they had been carried off by the Philistines; and although David at his death left numerous artificers, when his son built the temple and his own palace, he obtained mechanics from TYRE. It is moreover possible that the plaints and moanings incident to old age, when the grasshopper shall be a burden and desire shall fail,' were also intended to be pointed out by the perpetual creaking of these rickety machines, as indicative of approaching dissolution. The harsh noise they make has been noticed by several travelers. St. John speaks of the creaking sound of the water wheels; and Stephens, in his 'Incidents of Travel,' observes, "it was moonlight, and the creaking of the water wheels on the banks, (of the Nile) sounded like the moaning spirit of an ancient Egyptian."

ON THE ENGINE THAT RAISED WATER FROM THE EUPHRATES TO SUPPLY THE HANGING GARDENS AT BABYLON.

There is a machine noticed by ancient authors, which probably belongs to this part of our subject, and it is by far the most interesting hydraulic engine mentioned in history. Some circumstances connected with it, are also worthy of notice. It was constructed and used in the most ancient and most splendid city of the postdiluvian world; a city which according to tradition existed like Joppa, before the deluge: viz. BABYLON-a city generally allowed to have been founded by the builders of Babel; subsequently enlarged by Nimrod; extended and beautified by Semiramis; and which reached its acme of unrivaled splendor under Nebuchadnezzar. The engine which raised the water of the Euphrates to the top of the walls of this city, to supply the pensile or hanging gardens, greatly exceeded in the perpendicular height to which the water was elevated by it, the most famous hydraulic machinery of modern ages; and like most of the works of the remote ancients, it appears to have borne the impress of those mighty intellects, who never suffered any physical impediment to interfere with the accomplishment of their designs; and many of whose works almost induce us to believe that men were giants in those days.' The walls of Babylon, according to Herodotus, i, 178, were 350 feet high! Diodorus Siculus and others make them much less; but the descriptions of them by the latter, it is alleged, were applicable only, after the Persians under Darius Hystaspes retook the city upon its revolt, and demolished, or rather reduced their height to about 50 cubits; whereas the father of history gives their original elevation, and incredible as it may appear, his statement is believed to be correct. He is the oldest author who has described them; and he visited Babylon within one hundred and twenty years of Nebuchadnezzar's death; and four hundred before Diodorus flourished. He has recorded the impressions which at that time, the city made on his mind, in the following words, "its internal beauty and magnificence exceed whatever has come within my knowledge;" and Herodotus, it must be remembered, was well acquainted with the splendid cities of Egypt and the east. Had not the pyramids of Geezer, the temples and tombs of Thebes and Karnac, the artificial lakes and canals of Egypt, the wall of China, the caves of Ellora and Elephanta, &c.

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[Book 1. come down to our times; descriptions of them by ancient authors, would have been deemed extravagant or fabulous, and their dimensions reduced to assimilate them with the works of modern times: so strongly are we inclined to depreciate the labors of the ancients, whenever they greatly excel our own. According to Berosus, who is quoted by Josephus, Antiq. x, 11, it was Nebuchadnezzar who constructed these gardens, so that the prophet Daniel must have witnessed their erection, and also that of the hydraulic engine; for he was a young man when taken a captive to Babylon in the beginning of Nebuchadnezzar's reign, and he continued there till the death of that monarch and of his successor. Amytis, the wife of Nebuchadnezzar, was a Mede, and as Babylon was situated on an extensive plain, she very sensibly felt the loss of the hills and woods of her native land. To supply this loss in some degree, these famous gardens, in which large forest trees were cultivated, were constructed. They extended in terraces formed one above another to the top of the city walls, and to supply them with the necessary moisture, the engine in question was erected.

As no account of the nature of this machine has been preserved, we are left to conjecture the principle upon which it was constructed, from the only datum afforded, viz; the height to which it raised the water. We can easily conceive how water could have been supplied to the uppermost of these gardens by a series of machines, as now practised in the east to carry water over the highest elevations-but this is always mentioned as a single engine, not a series of them. Had its location been determined, that circumstance alone, would have aided materially in the investigation; but we do not certainly know whether it was placed on the highest terrace-on a level with the Euphrates-or at some intermediate elevation. The authors of the Universal History remark, "upon the uppermost of these terraces was a reservoir, supplied by a certain engine, from whence the gardens on the other terraces were supplied." They do not say where the engine itself was located. Rollin places it on the highest part of the gar dens : "In the upper terrace there was an engine or kind of pump by which the water was drawn up."

The statement of an engine having been erected at the top is probably correct, for we are not aware that the ancients at that period possessed any machine which, like the forcing pump, projected water above itself, Ancient machines, (and every one which we have yet examined, is an example,) did not raise water higher than their own level. But if sucking and forcing pumps were then known and used in Babylon, a period howev er, anterior to that of their alleged invention, of at least 500 years, still if this engine was placed on the uppermost terrace, both would have been wholly inapplicable. If therefore we incline to the opinion that this engine was a modification of one of those ancient machines, which we have already examined; we are not led to this conclusion by supposing the state of the arts in Babylon at the period of its construction, to have been too crude and imperfect to admit of more complex or philosophical

Paintings found in Pompeii, represent Villas of two stories having trees planted on their roofs. These kind of gardens were probably not very uncommon in ancient times in the east, though none perhaps ever equaled those of Babylon. They have been continued to modern times in Asia. Tavernier, when in Bagnagar (the modern Hyderabad) the capital of Golconda, found the roofs of the large courts of the palace terraced and containing gardens, in which were trees of such immense size "that it is a thing of great wonder how those arches should bear so vast a burden." The origin of these and of the city was similar to that of the Babylonian gardens. The King at the importunity of Nagar, one of his wives, founded the city and nained it after her Bagnagar-i. e, the gardens of Nagar."

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apparatus-on the contrary, we know that the Babylonians carried many of the arts to the highest degree of refinement. They were great contrivers," in this respect, and "fell short of no one nation under the sun, so far from it, that they in a great measure showed the way to every nation besides." Univer. His. Vol. i, 933. Besides, it is certainly more philosophical to suppose this famous engine to have been a modification of some machine, which we have reason to believe was used in Chaldea at that time, and capable of producing the results ascribed to the Babylonian engine, than of any other of which that people possibly knew nothing.

Of all ancient machines, the CHAIN OF POTS was certainly the best adapted for the purpose, and if we mistake not, the only one that could, with any regard to permanency and effect, have been adopted. It stands, and justly so, at the head of all ancient engines for raising water through great elevations; and it may be doubted whether any machine could now be produced better adapted for the hanging gardens of Babylon-either in the economy and simplicity of its construction; durability and effect; or be less liable to derangement, less expensive, or less difficult for ordinary people to repair. The project of raising water through a perpendicular elevation, exceeding three hundred feet, in numerous vessels attached to an endless chain, would probably startle most of our mechanicians; and some might suppose that the weight of so long a chain, if made of iron, would overcome the tenacity of the metal; but almost all the works of the remote ancients partook of the same bold features. Magnitude in some of their MACHINES, is as surprising as in other departments of their labors. Their engineers seem to have carried it to an extent that in modern days, would be considered as verging on the limits of the natural properties of materials.

That the chain of pots was the standard machine for raising water in quantities from great depths would appear from Vitruvius, since it is the only one adapted for that purpose which he has described, except the "machine of Ctesibius ;" and as he professes to give an account of the " various machines for raising water," and his profession as a civil engineer would necessarily render him familiar with the best of them, it is clear that he was ignorant of any other having been in previous use. That the engine at Babylon was no other than the chain of pots, may be inferred from the employment of the latter in Joseph's well, where it raises water to an elevation nearly equal to that ascribed to the former; and if the subject were of sufficient interest, we think a connection might be traced between them, if Joseph's well be, as supposed, a relic of Egyptian Babylon. Both Egypt and Chaldea were subject to the same monarch at the time that city was built. Twenty two or three years only had elapsed after Nebuchadnezzar's death when Cyrus took Babylon, and with it the empire; and nine years after he was succeeded by his son Cambyses, who when in Egypt, it is alleged, founded a city on the site of modern Cairo, and named it after old Babylon Cambyses reigned seven years and five months. If, therefore, the Babylonian machine was superior to the 'chain of pots,' (and it must have been, if it differed at all from the latter, for otherwise it would not have been selected,) then it would, we think, as a matter of course, have been adopted also in Joseph's well, in which the water was required to be elevated to about the same height as in the hanging gardens. Besides, if it possessed peculiar advantages, it would certainly have been preserved in use, as well as the chain of pots, for the wealth, comfort, and even existence of the people of the east, have at all times depended too much upon such machines to suffer any valuable one to be lost.

[Book I. Of

But was the chain of this machine formed of metal, or of ropes? the latter we have no doubt. They are generally made of flax or fibres of the palm tree at the present day over all the east. In great elevations, chains of rope possess important advantages over those of metal, in their superior lightness, being free from corrosion, and the facility of repairing them. But by far the most interesting problem connected with the Babylonian engine is, was the water of the Euphrates raised by it to the highest terrace at a SINGLE LIFT? If we had not been informed of one reservoir only, on the upper terrace "from whence the gardens on the others were watered," we should have supposed the water really raised as in Joseph's well, i. e. by two, or even more separate chains; and as it is, we cannot believe that so ingenious a people as the Babylonians would raise the whole of the water which the gardens required to the uppermost terrace, when the greatest portion of it was not wanted half so high. As the size of the terraces diminished as they approached the top of the walls, it is probable that full two thirds of the water was consumed within one hundred feet of the ground. We therefore conclude that this famous engine was composed of at least two, and probably more, separate chains of pots; and even then, it might with as much propriety, be noticed by ancient authors as a single machine, as that at Cairo still is, by all modern travelers. Winkelman says, the famous gardens at Babylon had canals, some of "which were supplied by pumps and other engines." And Kircher in his Turris Babel, 1679, represents fountains and jets d'eau on every terrace.

There is another device that belongs to this chapter. Every person knows, that where water is dispersed over extended surfaces, and of too limited depth to allow the use of a vessel to scoop it up, various substances are employed to absorb it, as sponge and woolen rags, and from which it is separated by pressure. A housemaid, when washing a floor, thus collects in a cloth the liquid dispersed in the purifying process; and by wringing returns it to the vessel. The process is substantially the same as that adopted to raise water in Vera's Rope Pump. See No. 57.

This machine consists of one or more endless ropes, formed of loosely

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spun wool or horse hair, and stretched on two pulleys like the endless chain of pots. These pulleys have grooves formed on their surfaces for the reception of the ropes. One of them is placed over the mouth of a well, and the other suspended in or secured to the bottom. A rapid motion is communicated to the upper pulley, by a multiplying wheel, and the ascending side of each rope then carries up the water absorbed by it; and which is separated from it when passing over the upper pulley, partly by centrifugal force, and partly by being squeezed in the deep groove, or by passing through a tube as shown in the figure. In the beginning of the motion, the column of water adhering to the rope, is always less than when it has been worked for some time, and continues to increase till the surrounding air partakes of its motion. By the utmost efforts of a man, nine gallons of water were raised by one of these machines from a well, ninety-five feet deep, in one minute. Adam's Philos. Vol. iii, 494.

The HYDRAULIC BELT is a similar contrivance. It is an endless double band of woolen cloth, passing over two rollers, as in figure 57. It is driven with a velocity of not less than a thousand feet per minute; when the water contained between the two surfaces is carried up and discharged as it passes over the upper roller, by the pressure of the band. Some machines of this kind are stated to have produced an effect equal to seventy-five per cent. of the power expended, while that of ordinary pumps seldom exceeds sixty per cent. See Lon. Mechan. Mag. Vol. xxix, page 431.

CHAPTER XVI.

THE SCREW-An original device-Various modes of constructing it-Roman Screw-Often re-invented -Introduced into England from Germany-Combination of several to raise water to great elevations— Marquis of Worcester's proposition relating to it, exemplified by M. Pattu-Ascent of water in it formerly considered inexplicable-Its history-Not invented by Archimedes-Supposed to have been in early use in Egypt-Vitruvius silent respecting its author-Conon its inventor or re-inventor-This philosopher famous for his flattery of Ptolemy and Berenice-Dinocrates the architect-Suspension of metallic substances without support-The screw not attributed to Archimedes till after his death-Invertions often given to others than their authors-Screws used as ship pumps by the Greeks-Flatterers like Conon too often found among men of science-Dedications of European writers often blasphemousHereditary titles and distinctions-Their acceptance unworthy of philosophers-Evil influence of scientific men in accepting them-Their denunciation a proof of the wisdom and virtue of the framers of the U. S. Constitution-Their extinction in Europe desirable-Plato, Solon, and Socrates-George IIIGeorge IV-James Watt-Arago-Description of the Syracusan,' a ship built by Archimedes, in which the Screw Pump was used.

THE COCHLEON or EGYPTIAN SCREW, the machine next described by Vitruvius, is, in every respect, the most original one of which he has given an account. Unlike the preceding, which appear to have been in a great measure deduced from each other, it forms a species of itself; and whoever was its inventor, he has left in it a proof of his genius, and a lasting monument of his skill. If it be not the earliest hydraulic engine that was composed of tubes, or in the construction of which they were introduced, it certainly is the oldest one known of that description; and in its mode of operation it differs essentially from all other ancient tube ma chines; in the latter the tubes merely serve as conduits for the ascending water, and as such are at rest; while in the screw it is the tubes themselves in motion that raises the liquid.