are nothing but many thousands of bubbles, which, being lighter than
air, would, you know, float on it."

"But, father," said John, "what makes it rain?"

"That is not certainly known," replied Mr. Harvey; "but, no doubt,
lightning has much to do with it. I will show you, this evening, several
pictures about clouds and springs of water, which will help you to
understand what I have said."

"Uncle," said Samuel, "there is one more question which I would like to
ask."

"Ask it, my boy," replied Mr. Harvey.

"I have read, sir, that the water of the ocean is salt; why, then, is
not rain water salt, too?"

"Because," said Mr. Harvey, "salt cannot be changed to vapor, and it is
too heavy to be raised, in any quantity, in the air with the water.
Yet, I suppose, that a little salt is always mixed with the bubbles that
form clouds."




CHAPTER VI.

HOW THOMAS KILLED A HAWK.