Page:Popular Science Monthly Volume 11.djvu/44

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34
THE POPULAR SCIENCE MONTHLY.

the course of the main and subsidiary conduits are 17 bridges, 3¾ miles of arcade, 4⅓ miles of siphon, and 17⅓ miles of tunnel. The work is done under the direction and supervision and in accordance with the designs of M. Belgrand. The total estimated cost, including $900,000 paid for injury to riparian rights, is $5,200,000.

The aqueduct which supplies the city of Manchester (England) with water is remarkable for its system of impounding reservoirs, comprising seven, with dams varying from 70 to 100 feet in height. The work was begun in 1848, and had not been completed in 1874, although it was far enough advanced to supply the city with water. The city of Glasgow is supplied by the Loch Katrine Aqueduct, 35 miles long, which conveys the water of the famous lake of that name. It consists of a conduit of masonry 8 feet deep, 8 wide, and 27 miles long, and two lines of cast-iron pipes, between the city and the service-reservoirs, 8 miles long. The conduit between Loch Katrine and the service-reservoirs is for the most part a tunmnel through solid rock. It crosses some ravines on stone or iron arcades, and others by siphons. It is capable of discharging 50,000,000 gallons per day. It was opened by the queen with appropriate ceremonies in October, 1859. The work was begun in 1855, and finished in 1860. The cost, exclusive of facilities for distribution, was $3,340,000.

In the autumn of 1873 was finished the aqueduct designed by Herr Carl Junker, of Vienna, and constructed by Mr. Antonio Gabrielli, of London, to convey the water of two springs (the Kaiserbrunn and Stixenstein), situated at the foot of the Styrian Alps, to Vienna, a distance of 56½ miles. The conduit, which varies in size from 4½ x 2½ feet to 6½ x 4 feet, and is faced with polished cement, to facilitate the flow of the water, is always six feet below the surface of the earth or embankment through which it is carried. The object aimed at is to keep the water cold in summer and from freezing in winter. It has several splendid arcades, chief among which are one at Baden, another at Mödling, and a third at Liesing. The former is 96 feet high, about 2,000 feet long, and comprises 43 arches. The aqueduct delivers about 20,000,000 gallons a day. It was begun in 1869, and its cost was $10,000,000.

But, in regard to water-supply, the Roquefavour Aqueduct, referred to previously, is by long odds the most remarkable. The conduit is 7 feet deep, 30 wide at the top, and 10 at the bottom. It discharges 11 tons of water per second, or about 285,000,000 gallons per day. The water is used for the city of Marseilles, and to irrigate 25,000 acres around it.

In our own country there are several noted aqueducts—as the Cochituate at Boston, the Washington Aqueduct, and Croton at New York. The method employed by the cities of Chicago and Milwaukee to obtain their water-supply is unique. The water of Lake Michigan is brought into the city by a tunnel from a sufficient distance off