The lower hull or main part of the craft was one hundred and fifty feet long, and forty feet through at the largest part, in the centre. It was divided into four sections. The forward one contained the sleeping quarters of Professor Henderson and his crew. There was a small stateroom for each one. Above was a conning or observation tower, reached by a small flight of steps. From this tower the ship could be steered, stopped and started, as could also be done from the engine room, which was in the after part of the hull. As in the _Porpoise_ and _Monarch_, electricity formed the motive power and was also used for many other purposes on board. Engines operated by gas produced the current which heated, lighted and moved the ship, as well as played a part in producing the wonderful gas. The ship moved forward or backward by means of a novel arrangement. This was by the power of compressed air. From either end of the lower hull there projected a short pipe working in a ball and socket joint, so it could be turned in any direction. By means of strong pumps a current of compressed air could be sent out from either pipe. Thus when floating above the earth the ship was forced forward by the blast of air rushing from the pipe at the stern. It was the same principle as that on which a sky rocket is shot heavenward, save that gases produced by the burning of powder in the pasteboard rocket form its moving impulse. In the case of the _Flying Mermaid_, it could be made to move backward by sending the air out of the forward tube. Thus, when in the water, the compressed air rushing from the pipe struck the fluid and forced the ship forward or backward as was desired. It floated on the surface, the deck being about three feet out of water, while the aluminum gas bag was overhead. The engine room was a marvel of machine construction. It contained pumps for air and water, motors, dynamos, gas engines, and a maze of wheels and levers. Yet everything was very compact and no room was wasted. The use of the air method of propulsion did away with the necessity of a large propellor such as most airships have to use, a propellor which must of necessity be very light and which is easily broken. Next to the engine room was the kitchen. It contained an electric range and all necessary appliances and utensils for preparing meals. There were lockers and a large reserve storeroom which when the time came would be well stocked with food. Forward of the kitchen was the living and dining room. It contained comfortable seats, folding tables and a small library. Here, also were many instruments designed to show how the various machines were working. There were gages, pointers and dials, which told the direction the ship was traveling, the speed and the distance above the earth or below the surface. Similar indicators were in the conning tower, which had a powerful search light.