ten o'clock
`` You do n't keep an office boy ? '' `` No . There would be nothing for him to do except to post a letter now and again , which Ritter does quite well for . '' `` As you are quite sure that the drawings were there at ten o'clock , perhaps the thing scarcely matters . But I may as well know if your men have keys of the office ? '' `` Neither . I have patent locks to each door and I keep all the keys myself .