Page:Miscellaneous Papers on Mechanical Subjects.djvu/173



71. Navy Yard, New York.—This navy yard is situated on Long Island, opposite the city. It covers a considerable extent of ground, and has many large storehouses and workshops, and gives employment to between 400 and 600 men.

It contains the most capacious dry dock in the United States, constructed to admit vessels of the largest size.

They may be completely docked, and the water pumped out in four hours and a quarter. The quantity of water to be removed is about 610,000 cubic feet. It is pumped out by a condensing engine, with a 60-inch cylinder, 12 feet stroke, and 32 feet beam.

The cut-off motion is self-adjusting, so that more steam is admitted into the cylinder as the height to which it has to pump the water increases.