The two vessels were safe but of no practical value, for lack of sufficient power to cope with the wind. Their motors were fundamentally unadapted to the purpose of swift propulsion, and incapable of development to very great lightness and strength. Furthermore, the vessels themselves were unsuitably designed for speed; their shape being one of too much resistance, and their dynamic balance being that of a pendulum, or clumsy parachute, rather than that of a vessel adapted to cleave the air with celerity, grace and steadiness. If there had been danger of fire from placing the motor and screw near the gas bag, that might justify or excuse the clumsiness of design in the craft of De Lome and of Gaston Tissandier; but, having perfectly safe motors, it is astonishing that they did not place the center of mass and the line of thrust more nearly in the line of resistance. This obvious requirement was duly recognized by several of their contemporaries, notably by Hänlein in Germany, and by Captain Renard of the French War Department, and had been observed by Jullien. Captain Charles Renard proved to be a worthy inheritor of the dreams, experience and inventions of the first century of aëronautical votaries. He did not, indeed, have the picturesque madness displayed by some of his predecessors; he did not project schemes of marvelous originality or boldness; but he manifested uncommonly good judgment and excellent scientific method in combining the researches and contrivances of others with those of himself and his collaborator, Captain Krebs. As a consequence they produced the first man-carrying dirigible that ever returned against the wind to its starting point, and the first aërial vessel whose shape and dynamic adjustment even approximated the requirements of steady and swift navigation in a surrounding medium presenting various conditions of turbulence or calm. Captain Renard had been studying and designing dirigibles since 1878 in coöperation with Captain La Haye and Colonel Laussedat, president of an aëronautic commission appointed by the Minister of War; and had endeavored to secure from the latter an appropriation sufficient to construct a dirigible; but his request was at first denied, owing to the waste of funds on similar projects in 1870. However, with the help of Gambetta, who promised a sum of $40,000, Renard was enabled to proceed. In the meantime he had been made director of the laboratory at Chalais Meudon, seconded by Captain Krebs. [Illustration: FIG. 20.—RENARD’S DIRIGIBLE, _La France_, 1884.]