The vessel was propelled—at a speed, it is thought, of about sixty miles an hour in still air—by means of six Maybach-Mercedes gasoline engines of 240 horse-power each, or 1,440 horse-power in all. Each had six vertical cylinders with overhead valves and water cooling, and weighed about 1,000 pounds. They were connected each to a propeller shaft through a clutch and change-speed gear, and also to a dynamo used either for lighting or for furnishing power to the wireless installation. One of these engines with its propeller was placed at the back of the large forward gondola, two were in the amidships gondolas, and three were in the aft gondola. In the last case one of the propellers was in the centre line of the ship, and the shafts of the other two were stayed out, one on either side. With the object of minimizing air resistance the stays were provided with a light but strong casing of two or three ply wood, shaped in stream-line form. The gasoline tanks had a capacity of 2,000 gallons, and the propeller shafts were carried in ball bearings. The date, July 14, 1916, marked on one of them, is thought to indicate the date of the launching or commissioning of the vessel. Forward of the engine-room of the forward gondola, but separated from it by a small air space, was first the wireless operator’s cabin and then the commander’s room. The latter was the navigating platform, and in it were concentrated the controls of the elevators and rudder at the stern, the arrangement for equalizing the levels in the gasoline and water tanks, the engine-room telegraphs, and the switchboard of the electrical gear for releasing the bombs. Provision was made for carrying sixty of the latter in a compartment amidships, and there was a sliding shutter, worked from the commander’s cabin, which was withdrawn to allow them to fall freely. Nine machine-guns were carried. Two of these, of 0.5-inch bore, were mounted on the top of the vessel, and six of a smaller caliber were placed in the gondolas—two in the forward, one each in the amidships ones, and two in the aft one. The ninth was carried in the tail. The separate gas-bags were a decided advantage over the free balloon and earlier airships which carried all the gas in one compartment, for if the latter sprang a leak for any reason it had to descend, whereas the Zeppelin could keep afloat with several of the separate compartments in a complete state of collapse.