"Men go up in them, don't they, aunt?" said James.
"Not in them, exactly," said his aunt. "They could not live in them, but they go up by means of them."
"How?" said Nathan.
"Why, they have a kind of basket, which hangs down below the balloon, and they get into that."
"I knew they could not get into the balloon," said Nathan.
"Then you have had a dispute about it," said his mother.
"Why,—yes," said Nathan, with hesitation, "we disputed a little."
"I am sorry to hear that," said his mother, "for disputing seldom does any good. The fact is, however, that men have often been carried up by balloons, but they never get into them. They could not live in them. They could not breathe the kind of air which balloons are filled with."
"It is hot air," said Nathan.
"No," said his mother, "the kind of balloon which your father told you of was filled with hot air; but the balloons which people generally use to go up with, are filled with another kind of air, which is very light when it is cool. They make an enormous bag of silk, and fill it with this light air, which they make in barrels; and then, when the bag is filled, it floats away above their heads, and pulls hard upon the fastening. There is a net all over it, and the ends of the net are drawn together below, and are fastened to the basket, or car, where the man is to sit. When it is all ready, the man gets into the car, and then they let go the fastenings, and away the great bag goes, and carries the man with it, away up into the air."