_Ventilating._--There were 12 electrically-driven fans for supplying air to the stokeholds, 6 electrically-driven fans for engine and turbine room ventilation. There were fans for engine and boiler rooms. MACHINERY. _Description._--The propelling machinery was of the combination type, having two sets of reciprocating engines driving the wing propellers and a low-pressure turbine working the center propeller. Steam was supplied by 24 double-ended boilers and 5 single-ended boilers, arranged for a working pressure of 215 pounds per square inch. The turbine was placed in a separate compartment aft of the reciprocating-engine room and divided from it by a water-tight bulkhead. The main condensers, with their circulating pumps and air pumps, were placed in the turbine room. The boilers were arranged in six water-tight compartments, the single-ended boilers being placed in the one nearest the main engines, the whole being built under board of trade survey for passenger certificate. _Reciprocating engines._--The reciprocating engines were of the four-crank triple-expansion type. Each set had four inverted, direct-acting cylinders, the high-pressure having a diameter of 54 inches, the intermediate pressure of 84 inches, and each of the two low-pressure cylinders of 97 inches, all with a stroke of 6 feet 3 inches. The valves of the high-pressure and intermediate cylinders were of the piston type, and the low-pressure cylinder had double-ported slide valves, fitted with Stephenson link motion. Each engine was reversed by a Brown type of direct-acting steam and hydraulic engine. There was also a separate steam-driven high-pressure pump fitted for operating either or both of the reversing engines. This alternative arrangement was a stand-by in case of breakdown of the steam pipes to these engines. _Turbine._--The low-pressure turbine was of the Parsons reaction type, direct coupled to the center line of shafting and arranged for driving in the ahead direction only. It exhausted to the two condensers, placed one on each side of it. A shut-off valve was fitted in each of the eduction pipes leading to the condensers. An emergency governor was fitted and arranged to shut off steam to the turbine and simultaneously change over the exhaust from the reciprocating engines to the condensers, should the speed of the turbine become excessive through the breaking of a shaft or other accident. _Boilers._--All the boilers were 15 feet 9 inches in diameter, the 24 double-ended boilers being 20 feet long, and the single-ended 11 feet 9 inches long. Each double-ended boiler had six and each single-ended boiler three furnaces, with a total heating surface of 144,142 square feet and a grate surface of 3,466 square feet. The boilers were constructed in accordance with the rules of the board of trade for a working pressure of 215 pounds per square inch. They were arranged for working under natural draft, assisted by fans, which blew air into the open stokehold.