IX
PROSPECTING BEGINS
We ceased to gaze. We turned to each other, the same thought, the same question in our eyes. For these plants to grow, there must be some air, however attenuated, air that we also should be able to breathe.
"The manhole?" I said.
"Yes!" said Cavor, "if it is air we see!"
"In a little while," I said, "these plants will be as high as we are. Suppose—suppose after all— Is it certain? How do you know that stuff is air? It may be nitrogen—it may be carbonic acid even!"
"That's easy," he said, and set about proving it. He produced a big piece of crumpled paper from the bale, lit it, and thrust it hastily through the man-hole valve. I bent forward and peered down through the thick glass for its appearance outside, that little flame on whose evidence depended so much!
I saw the paper drop out and lie lightly upon