Progress was very slow and gradual, a mere residue in a history of failures. The first use of the gas-engine was in an Austrian dirigible, which made a single captive ascent at Brunn in 1872, and developed a speed of three miles an hour. After 1870 the reconstituted French Government showed itself willing to encourage aeronautics, and in 1872, at the cost of the State, a large dirigible was built by Dupuy de Lome, the inventor of the ironclad. This ship, with an airscrew driven by manpower, attained a speed of five and a half miles an hour. The first really successful power-driven airship, that is, the first airship to return to its starting-point at the end of a successful voyage, was built in 1884 for the French army by Captain Krebs and Captain Charles Renard, who subsequently became director of the French department of military aeronautics. This dirigible, named _La France_, was fish-shaped; its length was a hundred and sixty-five feet; its greatest diameter, near the bows, was twenty-seven and a half feet, or one-sixth of its length; it was fitted with an electric motor of eight and a half horse-power which operated an airscrew of twenty-three feet in diameter, situated in front of the car; it was steered by vertical and horizontal rudders, and made several ascents in the neighbourhood of Meudon. It was the progenitor and type of all later non-rigid dirigibles. The success of _La France_ brought Germany into the field. Towards the close of the century a German engineer called Woelfert constructed a dirigible rather smaller than the French airship, with a slightly more powerful engine, and two airscrews of twelve feet in diameter. This was in one respect a forerunner of the most famous of the German airships, for the car, instead of hanging loose, was rigidly connected to the envelope by means of struts. The trials took place in 1896 at Tempelhof, near Berlin; the airship was held captive by ropes; it answered well to its rudders, and attained a speed of about nine miles an hour. Encouraged by this experiment, Dr. Woelfert in the following year built a second smaller dirigible, fitted with a Daimler benzine motor, and made a free ascent in it on the 14th of June 1897, near Berlin. As soon as it was well in the air, the ship caught fire and fell flaming to the ground, killing Dr. Woelfert and his assistant. Later in the same year the first completely rigid dirigible was built by a German called David Schwarz; it was made of thin aluminium sheeting, internally braced by steel wires, and was driven by a twelve horse-power Daimler motor which worked twin airscrews, one on either side. It took the air near Berlin on the 3rd of November 1897, but something went wrong with the airscrew belts, and it was seriously damaged in its hasty descent. Thereupon the crowd of people who had assembled to applaud it fell upon it, and wrecked it. The behaviour of the crowd deserves a passing mention in any