They are double forcing pumps and are connected, each of them, to an iron main of sixteen inches diameter, which is carried along the bottom of the race to the rock at the foot of Fairmount, and thence up the bank into the new reservoir. At the end of the pipe there is a stop-cock, which is closed when needful for any purpose. The shortest of these mains is two hundred and eighty-four feet long the other two are somewhat longer. The reservoir ;

next the bank is one hundred and thirty-nine feet by three hundred and sixty feet, is twelve feet deep, and contains three million of gallons it is connected at the bottom with ;

the old reservoirs by two of inches diameter with stop cocks. This reservoir pipes twenty contains four millons of All the water, being raised into the reservoirs one gallons. hundred and two feet above low tide, fifty-six feet above the highest ground in the city, is thence conveyed to the city, by iron pipes." On 24th October, 1822, the steam engines of the old work were stopped, never again, we presume, to be wanted. The actual consumption of water in Philadelphia, is stated at 2,000,000 " when the streets are washed." gallons in winter, and 3,000,000 in summer,

PRELIMINARY ESSAY. 79

The distribution of the water from Fairmount, is by two iron mains of 20 inches diameter, to the junction of Chestnut and Broad Streets ; and thence by intersecting pipes through various parts of the city ; superceding the wooden pipes, or bored logs, of the first works.