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 the snow. The pink flame of its burning vanished. For an instant it seemed to be extinguished. And then I saw a little blue tongue upon the edge of it that trembled, and crept, and spread!

Quietly the whole sheet, save where it lay in immediate contact with the snow, charred and shrivelled and sent up a quivering thread of smoke. There was no doubt left to me; the atmosphere of the moon was either pure oxygen or air, and capable therefore--unless its tenuity was excessive--of supporting our alien life. We might emerge--and live!

I sat down with my legs on either side of the manhole and prepared to unscrew it, but Cavor stopped me. "There is first a little precaution," he said. He pointed out that although it was certainly an oxygenated atmosphere outside, it might still be so rarefied as to cause us grave injury. He reminded me of mountain sickness, and of the bleeding that often afflicts aeronauts who have ascended too swiftly, and he spent some time in the preparation of a sickly-tasting drink which he insisted on my sharing. It made me feel a little numb, but otherwise had no effect on me. Then he permitted me to begin unscrewing.

Presently the glass stopper of the manhole was so far undone that the denser air within our sphere began to escape along the thread of the screw, singing as a kettle sings before it boils. Thereupon he made me desist. It speedily became evident that the pressure outside was very much less than it was within. How much less it was we had no means of telling.

I sat grasping the stopper with both hands, ready to close it again if, in spite of our intense hope, the lunar atmosphere should after all prove too rarefied for us, and Cavor sat with a cylinder of compressed oxygen at hand to restore our pressure. We looked at one another in silence, and then at the fantastic vegetation that swayed and grew visibly and noiselessly without. And ever that shrill piping continued.

My blood-vessels began to throb in my ears, and the sound of Cavor's movements diminished. I noted how still everything had become, because of the thinning of the air.

As our air sizzled out from the screw the moisture of it condensed in little puffs.

Presently I experienced a peculiar shortness of breath that lasted indeed during the whole of the time of our exposure to the moon's exterior atmosphere, and a rather unpleasant sensation about the ears and finger-nails and the back of the throat grew upon my attention, and presently passed off again.

But then came vertigo and nausea that abruptly changed the quality of my courage. I gave the lid of the manhole half a turn and made a hasty explanation to Cavor; but now he was the more sanguine. He answered me in a voice that seemed extraordinarily small and remote, because of the thinness of the air that carried the sound. He recommended a nip of brandy, and set me the example, and presently I felt better. I turned the manhole stopper back again. The throbbing in my ears grew louder, and then I remarked that the piping note of the outrush had ceased. For a time I could not be sure that it had ceased.

"Well?" said Cavor, in the ghost of a voice.

"Well?" said I.

"Shall we go on?"

I thought. "Is this all?"

"If you can stand it."

By way of answer I went on unscrewing. I lifted the circular operculum from its place and laid it carefully on the bale. A flake or so of snow whirled and vanished as that thin and unfamiliar air took possession of our sphere. I knelt, and then seated myself at the edge of the manhole, peering over it. Beneath, within a yard of my face, lay the untrodden snow of the moon.

There came a little pause. Our eyes met.

"It doesn't distress your lungs too much?" said Cavor.

"No," I said. "I can stand this."

He stretched out his hand for his blanket, thrust his head through its central hole, and wrapped it about him. He sat down on the edge of the manhole, he let his feet drop until they were within six inches of the lunar ground. He hesitated for a moment, then thrust himself forward, dropped these intervening inches, and stood upon the untrodden soil of the moon.

As he stepped forward he was refracted grotesquely by the edge of the glass. He stood for a moment looking this way and that. Then he drew himself together and leapt.

The glass distorted everything, but it seemed to me even then to be an extremely big leap. He had at one bound become remote. He seemed twenty or thirty feet off. He was standing high upon a rocky mass and gesticulating back to me. Perhaps he was shouting--but the sound did not reach me. But how the deuce had he done this? I felt like a man who has just seen a new conjuring trick.

In a puzzled state of mind I too dropped through the manhole. I stood up. Just in front of me the snowdrift had fallen away and made a sort of ditch. I made a step and jumped.

I found myself flying through the air, saw the rock on which he stood coming to meet me, clutched it and clung in a state of infinite amazement.

I gasped a painful laugh. I was tremendously confused. Cavor bent down and shouted in piping tones for me to be careful.

I had forgotten that on the moon, with only an eighth part of the earth's mass and a quarter of its diameter, my weight was barely a sixth what it was on earth. But now that fact insisted on being remembered.

"We are out of Mother Earth's leading-strings now," he said.

With a guarded effort I raised myself to the top, and moving as cautiously as a rheumatic patient, stood up beside him under the blaze of the sun. The sphere lay behind us on its dwindling snowdrift thirty feet away.

As far as the eye could see over the enormous disorder of rocks that formed the crater floor, the same bristling scrub that surrounded us was starting into life, diversified here and there by bulging masses of a cactus form, and scarlet and purple lichens that grew so fast they seemed to crawl over the rocks. The whole area of the crater seemed to me then to be one similar wilderness up to the very foot of the surrounding cliff.

This cliff was apparently bare of vegetation save at its base, and with buttresses and terraces and platforms that did not very greatly attract our attention at the time. It was many miles away from us in every direction; we seemed to be almost at the centre of the crater, and we saw it through a certain haziness that drove before the wind. For there was even a wind now in the thin air, a swift yet weak wind that chilled exceedingly but exerted little pressure. It was blowing round the crater, as it seemed, to the hot illuminated side from the foggy darkness under the sunward wall. It was difficult to look into this eastward fog; we had to peer with half-closed eyes beneath the shade of our hands, because of the fierce intensity of the motionless sun.

"It seems to be deserted," said Cavor, "absolutely desolate."

I looked about me again. I retained even then a clinging hope of some quasi-human evidence, some pinnacle of building, some house or engine, but everywhere one looked spread the tumbled rocks in peaks and crests, and the darting scrub and those bulging cacti that swelled and swelled, a flat negation as it seemed of all such hope.

"I............