state of collapse, and I
lost consciousness.

II

A STRANGE WORLD

I WAS UNCONSCIOUS LITTLE MORE THAN AN INSTANT, for as I lunged forward
from the crossbeam to which I had been clinging, and fell with a crash
to the floor of the cabin, the shock brought me to myself.

My first concern was with Perry. I was horrified at the thought that
upon the very threshold of salvation he might be dead. Tearing open
his shirt I placed my ear to his breast. I could have cried with
relief--his heart was beating quite regularly.

At the water tank I wetted my handkerchief, slapping it smartly across
his forehead and face several times. In a moment I was rewarded by the
raising of his lids. For a time he lay wide-eyed and quite
uncomprehending. Then his scattered wits slowly foregathered, and he
sat up sniffing the air with an expression of wonderment upon his face.

"Why, David," he cried at last, "it's air, as sure as I live. Why--why
what does it mean? Where in the world are we? What has happened?"

"It means that we're back at the surface all right, Perry," I cried;
"but where, I don't know. I haven't opened her up yet. Been too busy
reviving you. Lord, man, but you had a close squeak!"

"You say we're back at the surface, David? How can that be? How long
have I been unconscious?"

"Not long. We turned in the ice stratum. Don't you recall the sudden
whirling of our seats? After that the drill was above you instead of
below. We didn't notice it at the time; but I recall it now."

"You mean to say that we turned back in the ice stratum, David? That
is not possible. The prospector cannot turn unless its nose is
deflected from the outside--by some external force or resistance--the
steering wheel within would have moved in response. The steering wheel
has not budged, David, since we started. You know that."

I did know it; but here we were with our drill racing in pure air, and
copious volumes of it pouring into the cabin.

"We couldn't have turned in the ice stratum, Perry, I know as well as
you," I replied; "but the fact remains that we did, for here we are
this minute at the surface of the earth again, and I am going out to
see just where."

"Better wait till morning, David--it must be midnight now."

I glanced at the chronometer.

"Half after twelve. We have been out seventy-two hours, so it must be
midnight. Nevertheless I am going to have a look at the blessed sky
that I had given up