After the experiments of 1906, the Parseval air ship was enlarged from 2,500 to 2,800 cubic meters, its length becoming 52 meters and its major diameter 8.7 meters. Its hull was of cylindric form, with rounded bow and egg-shaped stern; had two air bags—one fore, the other aft—and at the stern carried two fixed horizontal planes and a vertical rudder. From this envelope the car, made largely of aluminum, was hung by steel cables, and on its bottom had trolley wheels resting on suspension cables joining the front and rear parts of the hull. The vessel was propelled by a 50-horse-power Mercedes motor actuating a four-blade screw propeller 13 feet in diameter, mounted between the car and hull. This screw was made of thin steel tubes covered with shirting. Among the merits of Parseval’s air ship may be mentioned its lightness and demountability, and its kite-like effect on the air, got by canting the hull while the car, rolling on the suspension cables, allowed the screw mounted above it to thrust horizontally. The canting was effected by giving one ballonet more air than the other, thus causing its end of the hull to sink. The speed was about twenty-five miles per hour. PLATE IX. [Illustration: _PARSEVAL I._ (Courtesy W. J. Hammer.)] [Illustration: _PARSEVAL II._ (Courtesy E. L. Jones.)] The second _Parseval_ was of greater bulk and power than her predecessor. Her hull which was of cylindric form, with round prow and pointed stern, measured 190 feet long, 30.5 feet in diameter, and 113,000 cubic feet in volume. She resembled her predecessor in the arrangement of the two ballonets, and in the “loose,” or trolley, system of suspension of the car. The propeller was a unique patented device of Von Parseval’s. It had four cloth blades so weighted with lead as to stand out firmly under centrifugal force, assuming an effective shape for propulsion, though limp and deformed when at rest. Various interesting evolutions were performed by this vessel in the autumn of 1908, including tests imposed by the military authorities, as a condition of purchase by the government, one requirement being a voyage of one hour at an altitude of 1,500 meters; another requirement being a continuous cruise of twelve hours. These tests completed, the Motor-Luftschiff-Studien-Gesellschaft sold its proud ship to the Vaterland for 210,000 marks.