about midnight
` I think it 's better , ' said Mary quietly , and then we undressed , so far as we could manage to do so in the extremely limited state of our toilet arrangements , and went to bed . `` I fell asleep at once . Mary , she afterwards told me , lay awake for an hour or two , so that when she did fall asleep her slumber was unusually profound . I think it must have been about midnight when I woke suddenly , with the feeling -- the indescribable feeling -- that something had awakened me . I listened , first of all with _ only _ the ear that happened to be uppermost -- then , as my courage gradually returned again , I ventured to move slightly , so that both ears were uncovered . No , nothing was to be heard . I was trying to compose myself to sleep again , persuading myself that I had been dreaming , when again -- yes most distinctly -- there _ was _ a sound .