About noon
Perry pulled it toward him , and once again we were plunging downward toward eternity at the rate of seven miles an hour . I sat with my eyes glued to the thermometer and the distance meter . The mercury was rising very slowly now , though even at 145 degrees it was almost unbearable within the narrow confines of our metal prison . About noon , or twelve hours after our start upon this unfortunate journey , we had bored to a depth of eighty-four miles , at which point the mercury registered 153 degrees F. Perry was becoming more hopeful , although upon what meager food he sustained his optimism I could not conjecture . From cursing he had turned to singing -- I felt that the strain had at last affected his mind . For several hours we had not spoken except as he asked me for the readings of the instruments from time to time , and I announced them . My thoughts were filled with vain regrets .