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."