"Why, the water above it was heavy, and pressed down upon it, and crowded it out through the hole."
"Yes," said his father, "and the deeper the water, the more heavily it was pressed."
"Yes, sir," said Rollo, "and the farther it spouted."
"Because it was pressed down by the load of such a high column of water."
"Yes, sir," said Rollo.
"Well," replied his father, "it is just so with the air. The air all around us is pressed down by the load of all that is above us. We are, in fact, down at the bottom of a great ocean of air, and the air here is loaded down very heavy."
"How heavy?" said Rollo.
"O, very heavy indeed," said his father.
"Why, air is pretty light," said Rollo.
"Yes," replied his father, "but then the column of it is very high."