"The third chamber was the engine-room. Here was all of the machinery used in operating the station: The main engines for the pumps (pipes from which ran to every compartment in the cylinder), for the fans for circulating fresh air; dynamos for electric lighting, pumps of the condensers, and, last, the three propellers, which were situated on the outside, on a level with the engine-room floor--two at 180 degrees apart, their faces parallel to the diameter of the cylinder, and the other at right angles to them and ninety degrees from either. These propellers were used to prevent any rotary motion of the cylinder. "Until lipthalite had been discovered--and it is now used--petroleum was the fuel for these engines, the vapors escaping through a tube extending to near the top of the first tower. Within the engine-room was a set of dials and bells which would give instant warning of the entrance of water into any compartment, tubes and telephones to all parts of the vessel; dials for pressure, submergence, state of electricity; levers for opening sand and water ports, etc. The fourth and fifth chambers were for stores and material. "The sixth contained the kitchen, mess, etc. "The seventh was the dormitory, while the eighth was the officers' cabin and office. Natural light was admitted into the last two chambers through bull's-eyes. "The office was provided with every instrument necessary in operating the station, and from it the sand and water ports could be opened. "The first tower was eight feet in diameter, tapering to five feet at the top, and fifty-one feet high. It was made of two-inch steel rings, six feet wide, firmly riveted together, the whole covered by aluminum plates. "The entrance to the vessel was through the tower, at the top of the frustum. A spiral stairway led to a port at the top, through which the upper balcony was reached. Bull's-eyes admitted light to the interior during the day. "The upper tower was forty feet high in the clear, setting down fifteen feet in the first tower, and was twenty inches in diameter, of one-inch cast steel. The interior of this tower was divided into a central pipe of ten inches diameter, surrounded by four pipes in the quadrants of its area. The central pipe was used for raising the electric lamp, of 25,000 candle power; the other pipes were, two for the engines, to carry off the vapors, etc., one for receiving fresh air into the vessel, and the other for carrying off the vitiated air. "Upon the side of the cone was a complete life raft, provisioned and ready for instant use, and so fastened that it could be launched at a moment's notice.