The United States War Department, in 1908, started an aërial squadron by purchasing from Thomas S. Baldwin, for $10,000, a tiny air ship of the flexible type, a trifle larger than Santos-Dumont’s _Runabout_, but in fact the smallest military dirigible then in existence. It had a rubberized gray silk cylindrical hull slightly tapering toward the rear and terminating in ogival ends, its length being 96 feet, its major diameter 19½ feet. From this was suspended, by means of netting and steel cables, a longish car having at the rear a double rudder working about a vertical hinge, at the front an elevating plane and an 11-foot wooden screw driven by a Curtiss 20-horse-power water-cooled engine. With two men aboard, this vessel readily attained over twenty miles an hour in a straightaway course, and at times more nearly thirty miles an hour. Its total ascensional force was 1,350 pounds, of which 500 were available for men, ballast and supplies. Santos-Dumont’s most strenuous disciples outside of France were found among the German military officers. These advocated and promoted both the semirigid and the flexible types of auto balloon, with such ability as to match the best productions of the foremost French designers. The most successful pioneers of these two types in Germany were respectively, Major von Gross, commander of the balloon battalion at Tegel, near Berlin, and Major Von Parseval of the Bavarian army, and director of the Society for the Study of Motor Air Ships. Beginning in 1907, a number of Gross auto balloons were built in succession, for the German Aëronautical Battalion, by Master Engineer Basenach, under the supervision of its commander, Major Gross. The first was intended only as a model, though it was large enough for two passengers. It cubed 63,000 feet, but having an engine of hardly more than 20 horse power, was necessarily slow. It was succeeded by the _Gross I_, and others, all having rigid ventral parts, like the _Patrie_, but with hulls of rather better form for speed and bulk combined, having blunter bow and longer stern. PLATE VIII. [Illustration: _U. S. SIGNAL CORPS DIRIGIBLE I._ (Courtesy U. S. Signal Corps.)] [Illustration: _GROSS II._ (Courtesy E. L. Jones.)] The second Gross air ship, built in 1908, cubed 176,000 feet, and attained a speed of 27 miles per hour, driven by two 75-horse-power Daimler motors. On September 11th of that year, with four persons aboard, she made a round trip from Berlin lasting 13 hours, covering 176 miles, and attaining altitudes up to 4,000 feet. This was one of the finest voyages known at the time. This air ship was purchased by the German government, named _Gross I_, and sent to Metz. A detailed description is given in Appendix III.