t is not harmful, I do not think the air
will have a pressure above ten or eleven, and we seem to need eighteen
or twenty for comfort. I shall be very sorry if we have to return at
once; but our supply of air is limited, you know."

"You keep a close watch through your telescope for those flying men you
promised to show me," I answered. "If they can live in this air, I think
we can manage it somehow. I will not go back while there is a breath
left in me."

But as we drew nearer and nearer to the surface we did not discover the
slightest sign of habitation. As far as we could see there was a great
desert, barren of all vegetation, and apparently unwatered since
creation. Our telescope did not detect the existence even of animals or
creeping things.

"The wisdom of the Creator is probably quite as profound, but certainly
not as apparent just here as it was somewhat farther back," I ventured.

"We must search over the whole surface of the globe until we find smoke
rising," said the doctor. "That is the sure sign of intelligent life on
Earth. There has hardly been a tribe of the lowest savages there which
did not know how to light a fire, and this knowledge would be far more
essential on a cold planet like this. Wherever we find smoke we shall
find those intellectual creatures, corresponding to men on our planet."

Presently, far ahead of us, we discerned a small black cloud rapidly
crossing our path. As we approached we examined it through the
telescope, and soon saw that it was nothing less than an enormous flock
of swiftly-flying small grey birds. This was our first acquaintance with
what we afterwards found to be the predominating form of animal life on
the planet. But the swift-winged cloud bore away from us, as if fleeing
from the desert, and was soon lost to view.

It was not long after this that we perceived a broad stripe of
brilliant green extending down into the dull expanse of the desert. In
the middle of this verdant zone there was a weaving silver ribbon, which
could be nothing else than a great river, along whose banks we could
discern hundreds of hovering or wading birds, hopping lugubriously, or
spreading their broad wings in a low flight.

As we now lowered rapidly to examine the soil more closely, we saw that
we were approaching some great geometrical masses of hewn rock, whose
regularity of design indicated that they were buildings of some sort. We
at once decided to land and investigate these, ev