"Certainly, we know why it rains."
"Why, Mr. Levin?"
The Forecaster pushed back his hat from his forehead and looked quizzically at the white-faced lad.
"You really want to know why rain comes? Very well, Anton, I'll try to tell you. Stop me, though, if you don't quite understand.
"The Earth goes whirling about in space, revolving around the Sun, as you know, and it has, like a sort of skin around it, an envelope of air. This air is kept from flying off by the force of gravity. You know what that is?"
"Yes, sir," the cripple answered, "it's what makes a stone fall to the ground."
"Exactly. Now the air is made up of little particles or molecules, like the stone, only, of course, not so heavy. They're heavy enough, though. How much weight of air do you suppose you're carrying, Anton?"
The boy looked puzzled.
"I don't quite see what you mean, sir," he answered.
"Suppose you had a pea on your head, it wouldn't be heavy to carry, would it?"