nearly three o'clock in the
morning
Congratulate me , my dear Holmes , and tell me that I have not disappointed you as an agent -- that you do not regret the confidence which you showed in me when you sent me down . All these things have by one night 's work been thoroughly cleared . I have said `` by one night 's work , '' but , in truth , it was by two nights ' work , for on the first we drew entirely blank . I sat up with Sir Henry in his rooms until nearly three o'clock in the morning , but no sound of any sort did we hear except the chiming clock upon the stairs . It was a most melancholy vigil , and ended by each of us falling asleep in our chairs . Fortunately we were not discouraged , and we determined to try again . The next night we lowered the lamp , and sat smoking cigarettes without making the least sound .