chain of pots, by passing the chain through a tight tube, round or square, and for pots substituting wooden or metallic pallets or pistons, fitting the interior of the tube and pushing the water before them, was known in China from the earliest ages, but does not appear to have been introduced into Europe till about the middle of the seventeenth century ; they are chiefly used now in an improved form on board ships of war. The ordinary pump, or sucking-pump, as it ^vas at first called, though evidently known to the Greeks and Romans, and used in their ships, does not seem to have been much employed by them for domestic purposes. It was not till the fifteenth and sixteenth century that pumps became common and superseded the more ancient devices for raising water — and even then the principle upon which the water was raised was little conceived of. The old doctrine of Aristotle, that nature abhorred a vacuum, was supposed to explain the whole matter, until one day a Florentine pump-maker having constructed a pump some 60 feet long, was astonished to find that he could not raise water in it more than 32 feet. As the Greek philosopher had^not assigned any limits to nature's abhorrence of a vacuum, it presented quite a problem, why in a pump it was found to be limited to a height of 32 feet. Torricelli, the disciple of Galileo, and after him, Pascal, the author of the admirable lettres provenqales, which so victoriously expose the dangerous and insidious doctrines of the Jesuits, by the most beautiful and PRELIMINARY ESSAY. 7 conclusive experiments, overthrew the long received notion of nature's abhorrence of a vacuum, and demonstrated that the rising of water in the chamber of the pump, was pro- duced by atmospheric pressure. As human beings were aggregated into larger societies, and the progress of civiliza- tion and refinement produced new and artificial wants, all the known modes of obtaining water from wells, springs, fountains and rivers, were found insufficient, and it became an object to devise some more compendious as well as abundant system of supply, and hence the resort to aqueducts. As nearly all the ancient aqueducts, of which there are still any remains, are of Roman construction, it has been generally believed that works of this description were entirely unknown to other people. This, however, is an error. Among the Greeks, some are mentioned by Pausanias and others. But no particular description of these structures has reached us, and we are therefore left to conjecture. As the use of the arch was. according to the received opinion, unknown to the Greeks, as well as the law of hydrostatics, that water will rise to its own level, it seems difficult to understand how they could pass water over valleys or streams ; and the inference seems reasonable, that their aqueducts, such as those built by Pisistratus, at Athens, that at Megara, and the celebrated one of Polycrates, at Samos, mentioned by Herodotus, were rather conduits than ranges of buildings like the Roman aqueducts. But, at a period antecedent probably to the construction of these Grecian aqueducts, King Solomon, one thousand years before the Christian Era, appears by the accounts of modern travellers, to have constructed a similar work. In the Universal History, vol. II, p. 441, we find the following statement : AdUEDUCT OF SOLOMON, " The pools of Solomon, so called, from his being commonly allowed to have caused them to be made, in order to supply not only his palace and gardens, but as some think, even the city of Jerusalem with water, appear still by what remains of them, to have been a work of immense cost and labor, and worthy of that great monarch. The same we may say, of the sealed fountains, which lie opposite to them, towards the north- west corner of the same hill, in the neighborhood of Bethlehem. These pools are three in a row, one over the other, and so disposed that the water of the uppermost may descend into the second, and from the second into the third. They are quadrangular, and of an equal breadth, viz., about 90 paces ; but in length they differ, the first being 160 paces, the second, 100, and the third, 220. All three are of a considerable depth, well walled and plastered, and contain a large quantity of water. About 120 paces distant is the spring which supplies them with water. The aqueduct is built on a foundation of stone, and the water runs in earthen pipes, about 10 inches in diameter, which are cased with two stones so as to fit them ; these are covered over with other, but rough 8 PRELIMINARY ESSAY. stones, well cemented together, and the whole