On the evening of his fall on the roof of the hotel Santos-Dumont issued specifications for his famous _No. 6_, which surpassed all its predecessors in safety and speed. It had the shape of an elongated ellipsoid with pointed ends, measured 110 feet in length, 20 feet in major diameter, 22,239 cubic feet in volume, and had an absolute ascensional force of 1,518 pounds. It was driven by a twelve horse-power four-cylinder water-cooled engine which gave the propeller a thrust of 145 pounds. To insure against buckling of the gas bag, an air pump connected with the motor, kept the ballonet under constant pressure, regulated by an escape valve through which the excess of air passed outward. To secure the envelope against rupture, due to the expansion of the hydrogen at unusual elevations, a stronger valve was used to let the gas escape from the envelope into the atmosphere. Thus the air escape valve kept the pressure constant in the partially distended ballonet, and consequently also in the surrounding gas envelope itself; while the stronger gas valve in the envelope opened only in an emergency, when the gas pressure had fully collapsed the internal air pocket and was threatening to explode the envelope. With all its improvements this new vessel was finished and inflated by August 4, being a work of twenty-two days, and after some preliminary trials was ready to try for the Deutsch prize. The day of triumph followed quickly. On October 19, 1901, at 2.45 P.M., Santos-Dumont again headed for the Eiffel Tower in presence of the official witnesses. In spite of a wind of six meters per second striking him sidewise, he held his course straight for the goal, and turned it in the ninth minute, as in his preceding attempt. On the return he had to struggle against a quartering wind and the caprice of his motor, which sometimes threatened to stop, and again spurted so actively as to turn the ship upward at a steep angle. The mighty throng below, in the Auteuil race track and the Bois de Boulogne, sent up immense applause, then suddenly held its breath in alarm, as the vessel pitched violently. But the hardy little rider was self-possessed and at home on his vaulting Pegasus. Alert to every prank he held his course straight for the timekeepers and passed over their heads at exactly twenty-nine and one-half minutes after starting.