From the very beginning of aëronautics difficulty was experienced in obtaining an envelope sufficiently impervious to gas to prevent excessive leakage, and yet not so heavy as to diminish unduly the ascensional power of the balloon. The first balloon, constructed by the brothers Montgolfier in 1783, was made of cotton fabric lined with paper and sewn on to a network of string. Faujas de Saint-Fond, who published a description of the experiment the same year, says that the gas escaped rapidly. Etiemne Montgolfier corroborates this, attributing the escape chiefly to the needle-holes in the envelope. Had the balloon not been of large size, 35 feet high and containing 22,000 cubic feet of air, it would probably have descended before the lapse of the ten minutes that the experiment lasted.