The circulating pumps are vertical, cross compound pumping engines with outside packed plungers. Their foundations are upon the basement floor level and the steam cylinders extend above the engine-room floor; the starting valves and control of speed is therefore entirely under the supervision of the engineer. Each pump has a normal capacity of 10,000,000 gallons of water per day, so that the total pumping capacity of all the pumps is 120,000,000 gallons per day. While the head against which these pumps will be required to work, when assisted by the vacuum in the condenser, is much less than the total lift from low tide water to the entrance into the condensing chambers, they are so designed as to be ready to deliver the full quantity the full height, if for any reason the assistance of the vacuum should be lost or not available at times of starting up. A temporary overload can but reduce the vacuum only for a short time and the fluctuations of the tide, or even a complete loss of vacuum cannot interfere with the constant supply of water, the governor simply admitting to the cylinders the proper amount of steam to do the work. The high-pressure steam cylinder is 10 inches in diameter and the low-pressure is 20 inches; the two double-acting water plungers are each 20 inches in diameter, and the stroke is 30 inches for all. The water ends are composition fitted for salt water and have valve decks and plungers entirely of that material. [Illustration: COAL UNLOADING TOWER ON WEST 58TH STREET PIER] The dry vacuum pumps are of the vertical form, and each is located alongside of the corresponding circulating pump. The steam cylinders also project above the engine-room floor. The vacuum cylinder is immediately below the steam cylinder and has a valve that is mechanically operated by an eccentric on the shaft. These pumps are of the close-clearance type, and, while controlled by a governor, can be changed in speed while running to any determined rate. [Sidenote: _Exhaust Piping_] From each atmospheric exhaust valve, which is direct-connected to the condensing chamber at each low-pressure cylinder, is run downward a 30-inch riveted-steel exhaust pipe. At a point just under the engine-room floor the exhaust pipe is carried horizontally around the engine foundations, the two from each pair of engines uniting in a 40-inch riser to the roof. This riser is between the pair of engines and back of the high-pressure cylinder, thus passing through the so-called pipe area, where it also receives exhaust steam from the pump auxiliaries. At the roof the 40-inch riser is run into a 48-inch stand pipe. This is capped with an exhaust head, the top of which is 35 feet above the roof.