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