AQUATINT. (Let. aqua, water, tints, dyed.) Iu engraving, a species of exe cution resembling an Indian ink drawing in CT. (Lat. aqua, water, and ductus, a conduit.) A conduit or chan nel for conveying water from one place to another ; more particularly applied to structures erected tor the purpose of con veying the water of distant springs across valleys, for the supply of large cities. The largest and most magnificent aque ducts, with the existence of which we are acquainted, were the work of the Romans ; and the ruins of several of them, both in Italy and other countries of Europe, remain to the present time monuments of the power and industry of that enterprising people. The aque duct of Apples Claudius was the most an cient, and constructed in the 442d year of Rome. It conveyed the Aqua Appia to the city, from a distance of between 7 and 8 miles, by a deep subterranean channel of more than 11 miles in length. The aqueduct of Quintus Martins was a more extraordinary structure. It com menced at a spring 33 miles distant from Rome, made a circuit of three miles, and afterwards, forming a vault of 16 feet diameter, it ran 38 miles, along a series of arcades at an elevation of 70 English feet. It was formed of three distinct channels, placed one above the other, conveying water from three different sources. In the uppermost flowed the Aqua Julia ; in the second, the Aqua Tepula • and in the undermost, the Aqua liiartia. The Aqua Virginia, con structed by Agrippa, passed through a tunnel of 800 paces in length. The Aqua Claudia, begun by Nero, and fin ished by Claudius, conveyed the water from a distance of 38 miles. This aque duct formed a subterrancous stream of 30 miles in length, and was supported on arcades through the extent of 7 miles ; and such was the solidity of its construe tion, that it continues to supply the modern city with water to the present day. The waters of the river Amo were also conducted to Rome by two different channels ; the first was carried through an extent of 43 miles, and the latter through upwards of 63 miles, of which 6t miles formed one continued series of arches, many of them upwards of 100 feet in height. Nine great aqueducts existed at Rome at the commencement of the reign of Nerva. Five others were constructed by that emperor, under the superintendence of Julius Frontinus ; and it appears that at a later period the number amounted to twenty. The sup
ply of water furnished by these different works was enormous. "According to the enumeration of Frontinus, the nine earlier aqueducts delivered every day 14,018 quinaria. This corresponds to 27,743,100 cubic feet. We may there fore extend the supply, when all the aqueducts were 'in action, to the enor mous quantity of 50,000,000 cubic feet of water. Reckoning the population of ancient Rome at a million, which it pro bably never exceeded, this would fur nish no less than '50 cubic feet for the daily consumption of each inhabitant." The remains of some Roman aqueducts in other parts of Europe give evidence of the existence of works on a still more mag nificent scale than those of Rome. Of these the aqueduct of Metz was one of the most remarkable. A number of its ar cades still remain. It extended across the Moselle, a river of very considerable breadth at this place, and conveyed the water of the Gorse to the city of Metz. The water was received in a reservoir, whence it was conducted by subterra neous canals, formed of hewn stone, and so spacious that a man might walk in them upright. The arches appear to have been 50 in number, and 50 feet high at the deepest part. Some of the middle ones have been swept away by the descent of ice down the river ; hose at the extremities still remain entire.
The aqueduct of Segovia, in Spain, is in a still more perfect state than that'of Metz. About of its arcades remain, all formed of large stones without ce ment. There are two rows of aread6s, the one the other, and the height of the edifice is about 100 feet, passing over the greater part of the houses of the city.
Aqueducts have been constructed in modern times, particularly in France, which rival those of the ancient Romans.
One of the moat remarkable was con structed by Louis XIV., for conveying the waters of the river Eure to Ver sailles. It extends about 4400 feet in length, or nearly seven-eighths of a mile, and is upwards of 200 feet in height. it contains 242 arcades, each divided into three rows, forming all 726 arches of i 50 feet span. The introduction of cast iron pipes, which has only taken place within the last century, has superseded the use of such expensive structures. (See CROTON AQUEDUCT.