WATER-SUPPLY. Water is one of the primary wants of human life, no less essential than air and food; hence the strong and religious interest that has always been attached to the means of its supply. In the earliest records of civilization, we read of the digging of wells, and of quarrels about the possession of them. The " pools of Solomon," near Bethlehem, which remain now almost as perfect as when they were built, were con nected with a scheme for supplying Jerusalem with water. In Assyria and Persia, from the earliest times, water has been conveyed to towns from astonishing distances in open channels or canals, and in subterranean tunnels, or kanats. In Egypt also, and in China, .gigantic works for conveying water, both for domestic use and for irrigation, have been in existence from remore antiquity. Nor were these undertakings confined to the east ern hemisphere; we have evidence of the existence of kindred works in pre-Christiau America. The ancient city of Mexico, which was built on several islands near the shore of the lake, was connected with the mainland by four great causeways or dikes, the remains of which still exist. One of these supported the wooden aqueduct of Chapol tepee, which was constructed by Montezuma, and destroyed by the Spaniards when they besieged the city. Hydraulic works on a great scale had also been executed by the Incas of Peru. Of all the ancient nations, the Romans paid the greatest attention to the supply of water, and carried the construction of aqueducts to the greatest perfection and magnificence. If we except the supply of New York from the Craton river (see AQUE DUCT), and that of Glasgow from loch Katrine, the efforts to supply modern cities are as yet insignificant compared with those of the Romans. The last-named works, finished in 1858, can convey 50,000,000 gallons a day a distance of 26 miles. It is only since the beginning of the sanitary movement, occasioned by the repeated visita tions of cholera beginning with 1832, that the subject of water-supply, and more especially the quality of- water-supply, has seriously occupied public attention. The result of every inquiry and every day's experience has been to bring out more strongly the decided effects on the health of a community arising from the quantity and quality of the water at their command; and as the river and surface sources of supply near the chief seats of population are becoming every year more contaminated by sewage (q.v.),
the drainage from manured laud, the droppings of animals, and the refuse of manu factures, enterprise and engineering skill must be directed either to procuring a supply of pure subterranean spring water from the chalk or other absorbent strata, or to bring ing pure water from greater distances than hitherto. In 1867 a royal commission was appointed to inquire into the condition of the water-supply of London; and numerous schemes were laid before them. Mr. Bateman proposed to utilize the high drainage grounds of north Wales, from which the river Severn is supplied, having an area 204 sq. miles. The water was to be conveyed for the most part in an open aqueduct 173 In. long, and capable of carrying 230,000,000 of gallons a day, to service-reservoirs on the high land near Stanmore, about 10 m. from London (from which it was to be delivered. at high pressure, by means of pipes, to the whole city). The total cost was estimated at £11,400,023. On the ground of the distance, the committee reported against the pro posal; as, on like grounds, they also did against a rival scheme for taking the supply from the lake districts of Cumberland and Westmoreland. Owing to the exceptionally great rain-fall in these regions (140 in. on an average), it is calculated that the two lakes of Ullswater and Haweswater, with a drainage of 100 sq.m., receive together an average -daily discharge of 550,000,000 gallons. From this water it was proposed to supply not only the metropolis. but the principal towns of the n.w. of England; but from various causes the scheme was abandoned. A bill has lately passed both houses of parliament to supply Manchester with water from Thirlmere. The Thames water has in some respects a superiority over the soft waters usually obtained from high gathering-grounds. It is well aerated, and keeps well. Recently, a covered conduit, 80 in. long, has been constructed, which conveys 8,000,000 gallons of pure chalk spring-water from the sources of the Dhuis, in Champagne, to Paris; and operations are about complete to bring the chalk springs of the Vanne, calculated to yield 22,000,000 gallons a day, also to Paris, a distance of 104 miles.