In a test recently made by experts with a Wheeler surface condenser, the temperature of injection water was 56 1-2 degrees, temperature of discharge 98 degrees, temperature of hot well 138 degrees, and vacuum 24 1-2 inches, 101.8 pounds of steam was condensed per hour per square foot of condensing surface.

In another test the condenser was worked as a simple surface condenser without vacuum, and with injection 78 1-2 degrees, discharge 139 degrees, hot well 201 degrees, 204.2 pounds of steam per hour per square foot of condensing surface was condensed.

The condensers are made with and without pumps attached, and with bodies of both circular and rectangular shape. The larger size are

usually of the latter design.

INDEPENDENT AIR AND CIRCLUATING PUMPING ENGINE.

The United States battle ship Maine is to have an entire outfit of steam pumps of the "Blake” type, including the independent air and circulating pumps for the marine engines (see Fig. 39).

The general design of this combined air and circulating pumping engine is similar to that now in use on the United States cruisers Chicago and Dolphin (which were also furnished by the same company), with the exception of the steam end of the machine, which is arranged on the