Having acquired experience and skill in operating both balloons and engines, the young enthusiast set about realizing his boyhood dream of navigating the air independently of the course of the wind. His first dirigible was designed to carry his weight of 110 pounds and a 3½ horse-power petroleum engine taken from his tricycle, and reduced in weight to 66 pounds. The hull was a cylinder of varnished Japanese silk, 82½ feet long including its pointed ends, 11½ feet in diameter and 6,354 cubic feet in gas capacity. A ballonet, or air pocket, occupied the lower middle of the envelope. The basket for the little pilot, engine, and two-blade propeller was suspended far below the hull, to which its cords were attached by means of small wooden rods inserted into hems along each side of the envelope, for a great part of its length. The poise of the vessel was controlled by shifting weights fore and aft, while the turning right and left was effected by means of a silk rudder stretched over a steel frame. On the whole it was a crude and primitive affair, but of considerable interest as the first dirigible of a young man destined to give a strong impulse to the development of motor balloons of the non-rigid type. After some preliminary tests, the little air ship and pilot soared away from the Zoölogical Garden in Paris, on September 20, 1898, rising in the face of a gentle wind, to the wonder and delight of a large crowd of witnesses, some of them professional aëronauts and very skeptical as to the outcome of this venturesome experiment. The ship maneuvered round and round overhead of the applauding throng, steering readily in all directions. Then the green navigator ascended a quarter of a mile and merrily continued his evolutions in the direction of the Longchamps race course. But when he wished to descend he observed the envelope contracting in volume, and was appalled to find that he could not pump air into the ballonet fast enough to keep the hull distended. It became swaybacked, and “all at once began to fold in the middle like a pocket-knife; the tension cords became unequal and the balloon envelope was on the point of being torn by them.” As he was falling swiftly toward the grassy turf at Bagatelle, he called to some boys who were flying kites, to grasp his guide-rope and run against the wind. They understood and ran so swiftly with the canted balloon that it played kite, and descended with a moderated fall, landing the frightened aëronaut safely on the turf.