Page:The American Cyclopædia (1879) Volume XVI.djvu/531

 WATER WORKS 511 from Jamaica pond to the pump well the width is 10 ft., and the descent 6 in. per mile. This portion of the conduit is capable of delivering, with 32 in. depth of water, 20,000,000, and with a depth of 5 ft. 47,000,000 gallons of wa- ter in 24 hours. A portion of the conduit rests upon pile foundations, and it is supported all the way by a bed of concrete 15 ft. wide. The bottom is an inverted arch of brick 4 in. thick, with a versed sine of 8 in. The top is a brick arch 12 in. thick, the height from the centre being 8 ft. 8 in. At convenient points along the line there are man holes, at the top or on the side, affording access for inspection or re- pairs. On this lower reach, between Jamaica and the puinp well, the sides are of stone, 3 ft. high, with a lining of brickwork. Above this the brickwork is omitted. For nearly the whole length the aqueduct is covered with 4 ft. of earth, sloping from 1 perpendicular to 1 aQ d 2 horizontal. At the pump well the aqueduct ter- minates in an arched basin 52 ft. long, at right angles to its course, and connecting with the pump well by four sluices. The total length of the aqueduct is 12-39 m., 7-J- m. of which is 10 ft. wide and 8 ft. high. The pump well is of heavy granite masonry laid in hydraulic cement. The bottom, 2 ft. below that of the aqueduct, rests upon a bed of concrete, which in turn rests upon a heavy platform of timber. From this well the pumping engines raise the water 164 vertical feet into the Ridgewood reservoir. These engines are three in number, two beam' and one crank engine, their united capacity being about 32,000,000 gallons in 24 hours. The reservoir is in two divisions, one having an area of 11-85 and the other 13'73 acres; the water surface when filled to a depth of 20 ft. being 170 ft. above high-water mark. The em- bankments contain puddle walls carried 2 ft. higher than the level to which the reservoir is filled, and the bottom is also puddled with clay. The inner slopes are paved with broken bowl- der stone upon a bed of stone chips and gravel. The water flows into the reservoir from bell- shaped mouths of the force mains into an influx chamber of heavy stone masonry, and from these over an apron into each compartment of the reservoir. In traversing a distance of 1,200 ft. in the reservoir most of the sediment is de- posited. The effluent chamber, also of massive stone masonry, has four sluice ways, and is separated from the stopcock chamber by a heavy stone wall 6 ft. thick, from which issue three mains, each 36 in. in diameter. Before entering the effluent chamber, the water passes through screens of copper wire. The total ca- pacity of the reservoir is 161,090,444 gallons. At Mt. Prospect there is a reservoir with a ca- pacity of 20,000,000 gallons for the supply of the higher portions of the city, which is filled by a pumping engine having a capacity of 112 gallons at each stroke. The force main has a 20-inch branch connecting with the effluent main, which may be used when the reservoir needs cleaning or repair, in which case the 20- 829 VOL. xvi. 33 inch main leading up to the influent chamber would act as a retard pipe to regulate the flow. The city of Philadelphia is supplied with water from the Schuylkill river by the Fairmount water works. The original works at Fair- mount, driven by steam power, were com- menced Aug. 1, 1812, to take the place of works which were in operation at Chestnut and Broad streets, and which were also worked by steam power. The Fairmount works were put in operation Sept. 7, 1815. At the foot of Fairmount hill there was erected a Boulton and Watt engine of 44 in. cylinder and 6 ft. stroke, working a double-acting pump of 20 in. diam- eter and 6 ft. stroke, raising the water through a 16-inch main 239 ft. long into a reservoir 102 ft. above low water in the Schuylkill river. Measures were taken in 1819 to use water power, and a dam was constructed across the Schuylkill, which was completed July 28, 1821. This dam, 1,600 ft. long, of hemlock, was re- built in 1842-'3 from low tide with white pine. The building of the present new dam was commenced in June, 1872, in front of the old one, upon a rock at the west end, and upon cribs at the east end. The breadth of overflow is 1,112 ft. The first wheel, a breast wheel, was put in operation July 1, 1822, and the ninth, a turbine, Dec. 16, 1851. The total quantity of water pumped in 1852 was 2,092,- 086,692 gallons. In 1866, 1867, and 1868, the daily average pumping was nearly 22,000,000 gallons. Since then more than $600,000 have been expended in constructing the new dam, new wheel house, and three new turbines, but the daily average supply has never equalled 25,000,000 gallons, which demonstrates the fact that the system is not as economical as that which employs steam power. The pump- age during 1875 was 7,670,009,198 gallons, a daily average of 21,013,724.' The other works which supply Philadelphia with water employ steam engines, except the syphon, which takes the water from the Wissahickon and empties it into a basin at Mt. Airy. The capacity of the Spring Garden works is 22,000,000 gallons daily. On May 10, 1876, at the opening of the centennial exhibition, a new engine of 20,- 000,000 gallons capacity was put in operation. There are also the Delaware, Belmont, Rox- borough, Chestnut Hill, and Frankford works. The third system of water works, called the Holly system, owes one of its principal advan- tages to the fact that it is the best possible sys- tem for extinguishing fires, and also for keeping all the supply pipes constantly filled and main- taining a nearly equable pressure in them. It may employ steam or water as a power, and with a sufficient reserve force to allow of 100 Ibs. or more to a square inch to be brought against the water in the pipes. The city of Rochester, K Y., is supplied by the Holly sys- tem, having a dual arrangement: 1. Water is pumped from the Genesee river by a steam engine, which throws it directly into the sup- ply pipes. The machinery runs constantly,