about three o'clock in the morning
About that time some one heard me and came out like a bullet . The next thing I knew , everything was closed . How long the experiments had been going on , I could n't say . I do know , however , that they did n't leave there until about three o'clock in the morning . '' `` You -- you do n't know who the men were ? '' Houston , forcing himself to be casual , had asked the question . The young doctor shook his head .