“There, I throw myself on your discretion.  I’m not a practical man, of course, but don’t you think they will regard it as a cyclone?”

“But the explosion—­”

“It was not an explosion.  It’s perfectly simple.  Only, as I say, I’m apt to overlook these little things.  Its 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 things from gravitating towards each other?”

“Yes,” said I.  “Yes.”

“Well, so soon as it reached a temperature of 60 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 in 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 upward 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 atmospheric fountain, a kind of chimney in the atmosphere.  And if the Cavorite itself hadn’t been loose and so got sucked up the chimney, does it occur to you what would have happened?”

I thought.  “I suppose,” I said, “the air would be rushing up and up over that infernal piece of stuff now.”

“Precisely,” he said.  “A huge fountain—­”

“Spouting into space!  Good heavens!  Why, it would have squirted all the atmosphere of the earth away!  It would have robbed the world of air!  It would have been the death of all mankind!  That little lump of stuff!”

“Not exactly into space,” said Cavor, “but as bad—­practically.  It would have whipped the air off the world as one peels a banana, and flung it thousands of miles.  It would have dropped back again, of course—­but on an asphyxiated world!  From our point of view very little better than if it never came back!”

I stared.  As yet I was too amazed to realise how all my expectations had been upset.  “What do you mean to do now?” I asked.