Page:Barbour--For the freedom from the seas.djvu/166

 and seven men. It was quite a spacious chamber, as it needed to be in order to accommodate all those necessary to navigate the boat under water. A ladder led upward to the conning tower above and a bench ran along one side, but for the rest the furnishings of the central station were all mechanical. Dials, valves, gyroscope compass, manifolds, steering and diving wheels, depth gauges, levers, clinometer for determining the boat's inclination, motor controllers, engine room telegraph, navigating lights, voice pipes and other things were indicated by Martin. Here was the brain of the craft. Every activity was controlled from this white-walled, light-flooded chamber and from it wires and pipes led forward and aft like nerves. Two gunner's mates were at the big brass wheels controlling the diving rudders, while in front of them a gauge indicated the boat's depth. Their duty, explained Martin, was to keep the submarine on an even keel, and at the depth ordered by the navigating officer, by means of the forward and aft diving rudders. Near them a mechanic presided over the air and water manifolds of the ballast and trimming tanks. A fourth man was in charge of the Kingston valves which flooded the main ballast tanks during submergence. A steersman was at the wheel to the left of the 141