four o'clock
`` If you wish to know who administered that aconitine poison , you will have to find out who Jimmie was with at the McIntyre house in the early hours of Tuesday morning . '' The sharp imperative ring of the telephone bell cut the silence which followed . Kent , standing nearest the instrument , picked it up , and recognized Sylvester 's voice over the wire . `` A message has just come , Mr. Kent , '' he called , `` from Mrs. Brewster saying that she will be in your office at four o'clock . '' Harry Kent inserted his key in his office door with more vigor than good judgment , and spent some seconds in re-adjusting it in the lock . Once inside the office he put up the latch and closed the door . A glance around the empty office showed him that Sylvester had obeyed his telephone instructions and gone out to luncheon .