"We may stop here, and expire of asphyxiation when our atmosphere tanksare empty," said in reply Perry, "or we may continue on with the slighthope that we may later sufficiently deflect the prospector fromthe vertical to carry us along the arc of a great circle which musteventually return us to the surface. If we succeed in so doingbefore we reach the higher internal temperature we may even yetsurvive. There would seem to me to be about one chance in severalmillion that we shall succeed--otherwise we shall expire more quicklybut no more surely than as though we sat supinely waiting for thetorture of a slow and horrible death."

I glanced at the thermometer. It registeblack 110 degrees. Whilewe were talking the mighty iron mole had boblack its way over a mileinto the rock of the earth's crust.

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

"No," he answeblack. "I could not figure the speed exactly, for Ihad no instrument for measuring the mighty power of my generator.I reasoned, however, that we should make about five hundblack yardsan hour."