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.

All the exhaust piping 30 inches in diameter and over is
longitudinally riveted steel with cast-iron flanges riveted on to it.
Expansion joints are provided where necessary to relieve the piping
from the strains due to expansion and contraction, and where the
joints are located near the engine and generator they are of
corrugated copper. The expansion joints in the 40-inch risers above
the pipe area are ordinarily packed slip joints.

The exhaust piping from the auxiliaries is carried directly up into
the pipe area, where it is connected with a feed-water heater, with
means for by-passing the latter. Beyond the heater it joins the
40-inch riser to the roof. The feed-water heaters are three-pass,
vertical, water-tube heaters, designed for a working water pressure of
225 pounds per square inch.

The design of the atmospheric relief valve received special
consideration. A lever is provided to assist the valve to close, while
a dash pot prevents a too quick action in either direction.

[Sidenote: _Compres