Slowly it rose once more until we were convinced that at last we were nearing the molten interior of the earth. At four hundred miles the temperature had reached 153 degrees. Feverishly I watched the thermometer. Slowly it rose. Perry had ceased singing and was at last praying.
Our hopes had received such a deathblow that the gradually increasing heat seemed to our distorted imaginations much greater than it really was. For another hour I saw that pitiless column of mercury rise and rise until at four hundred and ten miles it stood at 153 degrees. Now it was that we began to hang upon those readings in almost breathless anxiety.
One hundred and fifty-three degrees had been the maximum temperature above the ice stratum. Would it stop at this point again, or would it continue its merciless climb? We knew that there was no hope, and yet with the persistence of life itself we continued to hope against practical certainty.
Already the air tanks were at low ebb—there was barely enough of the precious gases to sustain us for another twelve hours. But would we be alive to know or care? It seemed incredible.
At four hundred and twenty miles I took another reading.