our own immediate future than with any problematic loss which the
world might be about to suffer. The world was at least ignorant
of its bereavement, while to me it was a real and terrible actuality.

"What can we do?" I asked, hiding my perturbation beneath the mask
of a low and level voice.

"We may stop here, and die of asphyxiation when our atmosphere tanks
are empty," replied Perry, "or we may continue on with the slight
hope that we may later sufficiently deflect the prospector from
the vertical to carry us along the arc of a great circle which must
eventually return us to the surface. If we succeed in so doing
before we reach the higher internal temperature we may even yet
survive. There would seem to me to be about one chance in several
million that we shall succeed--otherwise we shall die more quickly
but no more surely than as though we sat supinely waiting for the
torture of a slow and horrible death."

I glanced at the thermometer. It registered 110 degrees. While
we were talking the mighty iron mole had bored its way over a mile
into the rock of the earth's crust.

"Let us continue on, then," I replied. "It should soon be over at
this rate. You never intimated that the speed of this thing would
be so high, Perry. Didn't you know it?"

"No," he answered. "I could not figure the speed exactly, for I
had no instrument for measuring the mighty power of my generator.
I reasoned, however, that we should make about five hundred yards
an hour."