Why did Jonas suppose that the stump would not burn? What was Rollo's first mode of setting it on fire? How did it succeed? What did Jonas do with his axe, when he came? What was the object of this? What did he say was necessary to make fires burn? What did Rollo at first think was the reason why the bark went out when held over the fire? What did he next think was the reason? How did Jonas say that different kinds of airs were prepared? In what places did he say that choke damp was naturally produced? How did they attempt to prepare some of this gas? Did they succeed in preparing it? Did they succeed in their experiment at first? What was the cause of the failure?
CHAPTER X.
GRAVITATION.
One evening, after tea, when Rollo was a pretty big boy, he came and began to climb up into his father's lap. When he had climbed up, he took his place astride of his father's knee, as if he were riding a horse. His little brother Nathan came up and stood near, wanting to get up too, only there was not room. His cousin James was there, that evening, on a visit. He sat upon a cricket before the fire, and his mother was at the table doing some sort of work.
"O dear me!" said Rollo's father, imitating the tone in which Rollo sometimes uttered that exclamation.
"What, sir?" said Rollo.
"Why, I should like very well to hold you in my lap," said his father, "if it was not for the great mighty earth, down below us."
"How?" said Rollo. He did not know what his father meant.
"Why, when you are upon my knee, the earth, the ponderous earth, pulls you down hard and heavy upon it." So saying, he put his hands upon Rollo's shoulders, and crowded them down, by way of showing him how the earth acted upon him. "It pulls," he continued, "with a strong and steady pull, all the time; and so makes you a very heavy weight."