"It would continue ascending till it reached a layer of air as light as the gas; beyond that point it could not go."
"And if the voyagers do not wish to go quite so far?"
"Then there is a valve by which the gas may be allowed to escape, till the weight of the machine and its volume of air are equal, when it ceases to ascend. If a little more is permitted to escape, the balloon descends."
"And should it land on the roof of a house or the top of a tree, the voyagers have their necks broken."
"That can only happen to bunglers; there is not the least necessity for landing where danger is to be apprehended. When the aeronaut is near the ground, and sees that the spot is unfavorable for debarkation, he drops a little ballast, the balloon mounts, and he comes down again somewhere else."
"The fellow that made the first voyage must have been very daring."
"The first ascent was made by Montgolfier in 1782, and he was followed by Rosiers and d'Arlandes."
"With your permission, father," said Ernest, "I will claim priority in aerial travelling for Icarus, Doedalus, and Phaeton."
"Certainly; you are justified in doing so. Gay-Lussac, a philosophic Frenchman, rose, in 1804, to the height of seven thousand yards."
"He must have felt a little giddy," remarked Jack.