About eleven o'clock in the morning
He fixed shelves in the stone , arranged the materials from their packs , and all the time he whistled airs , until the cavern seemed to be filled with the singing of nightingales , mocking birds and skylarks . Will and Boyd began to help him , though Will stopped at times to look out . On every occasion he reported that the snow was still drifting down in a steady , thick , white stream , and that he could not see more than thirty or forty yards from the door . About eleven o'clock in the morning , when he pulled the bearskin aside for perhaps the sixth time , he heard a sound which at first he took to be the distant moan of the wind through a gorge . But he had not heard it on his previous visits , although the wind had been blowing all the morning , and he stood there a little while , listening . As he did not hear it again just yet , he thought his fancy had deceived him , but in a minute or so the sound came once more . It was a weird note , carrying far , but he seemed to detect a human quality in it .