midnight
The air outside was still ; the flame of the lamp could hardly make sound . Trenholme 's watch , which lay on the table , ticked and seemed to clamour for his attention . He glanced down at it . It was not very far from midnight . Just then he heard another sound . It was possibly the same as that which came to him an hour ago , but more continuous . There was no mistaking this time that it was an unusual one .