THE FIRST MAKING OF CAVORITE
It's that zuzzoo business on a larger scale. Inadvertently I made this substance of mine, this Cavorite, in a thin wide sheet. . . ."
He paused. "You are quite clear that the stuff is opaque to gravitation, that it cuts off objects from gravitating towards each other?"
"Yes," said I. "Yes?"
"Well, so soon as it reached a temperature of sixty degrees Fahrenheit and the process of its manufacture was complete, the air above it, the portions of roof and ceiling and floor above it ceased to have weight. I suppose you know—everybody knows nowadays—that, as a usual thing, the air has weight, that it presses on everything at the surface of the earth, presses in all directions, with a pressure of fourteen and a half pounds to the square inch?"
"I know that," said I. "Go on."
"I know that too," he remarked. "Only this shows you how useless knowledge is unless you apply it. You see, over our Cavorite this ceased to be the case, the air there ceased to exert any pressure, and the air round it, and not over the Cavorite, was exerting a pressure of fourteen pounds and a half to the square inch upon this suddenly weightless air. Ah! you begin to see! The air all about the Cavorite crushed in upon the air above it with irresistible force. The air above the Cavorite was forced upwards violently, the air that rushed in to replace it immediately lost weight, ceased to exert any pressure, followed suit, blew the ceiling through and the roof off. . . .
"You perceive," he said, "it formed a sort of at-
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