midnight
You know that . '' I did know it ; but here we were with our drill racing in pure air , and copious volumes of it pouring into the cabin . `` We could n't have turned in the ice stratum , Perry , I know as well as you , '' I replied ; `` but the fact remains that we did , for here we are this minute at the surface of the earth again , and I am going out to see just where . '' `` Better wait till morning , David -- it must be midnight now . '' I glanced at the chronometer . `` Half after twelve . We have been out seventy-two hours , so it must be midnight .