Aq'ueduct, an artificial channel or conduit for the conveyance of water from one place to another. The name is more particularly applied to structures for conveying water from distant sources for the supply of large cities. Aqueducts were extensively used by the Romans, and many of them still remain in different places on the continent of Europe, some being still in use. The Pont du Gard in the south of France, 14 miles from Nimes, is still nearly perfect, and is a grand monument of the Roman occupation of that country. The ancient aqueducts were constructed of stone or brick, sometimes tunneled through hills and carried over valleys and rivers on arches. The Pont du Gard is built of great blocks of stone; its height is 160 feet, and the length of the highest arcade is 882 feet. The aqueduct at Segovia, originally built by the Romans, has in some parts two tiers of arcades 100 feet high, is 2921 feet in length, and is one of the most admired works of antiquity. One of the most remarkable aqueducts of modern times is that constructed by Louis XIV for conveying the waters of the Eure to Versailles. The extensive application of metal pipes has rendered the construction of aqueducts of the old type unnecessary; but what may be called aqueduct bridges are still frequently constructed in connection with waterworks for the supply of towns. Where canals exist, canal aqueducts are common since the water in a canal must be kept on a level. In the United States there are some important aqueducts, as the Croton, about 40 1/2 miles long, bringing water to New York (See CROTON AQUEDUCT). The aqueduct or flume which conveys the water from the mountains to the reservoir at San Diego, Cal., is 35 miles long and is built almost wholly of redwood. It crosses 315 streams and canyons, on trestles, the longest of which is 1700 feet and has a height of 85 feet. The timbers used in these trestles were put together on the ground and raised to their position by horse power. This aqueduct passes also through eight tunnels, the longest being 2100 feet.