The scientist tapped his fingers on the arm of his chair in pleased appreciation.
"Very good," he said, "you are exactly right. And, from now on, the barometer will drop suddenly, for the whirl of the wind will make a partial vacuum in the very center of the hurricane."
"But I don't see what makes it whirl," protested the boy. "If it goes up in the middle, flows over at the top and comes down at the outside and then flows into the middle again, why could it not keep on doing that all the time, until the balance was put straight again?"
"It would," the scientist agreed, "but for one thing you have forgotten."
"And what's that?"
"The rotation of the earth."
A single drop of rain fell, then another, making a splash as large as a twenty-five cent piece.
"Now see it come!" said the scientist.
As though his words had summoned it, a liquid opacity, like a piece of clouded glass, thrust itself between their eyes and the landscape. So suddenly it came that Stuart actually did not realize that this was falling rain, until, looking at the ground, he saw the earth dissolve into mud before his eyes and saw the garden turn into what seemed like the bed of a shallow river. The wind whistled with a vicious note. The squall lasted scarcely a minute, and was gone.
"That's the first," remarked the boy's informant. "We'd better get under shelter, they'll come fast and furious soon."