four o’clock
She could only be in Mrs. Macallan 's room -- the _ one _ room which had baffled my investigations ; the _ only _ room which had not lent itself to examination . Add to this that the key of the door in the study , communicating with Mrs. Macallan 's room , was stated in the nurse 's evidence to be missing ; and do n't forget that the dearest object of Mrs. Beauly 's life -LRB- on the showing of her own letter , read at the Trial -RRB- was to be Eustace Macallan 's happy wife . Put these things together in your own mind , and you will know what my thoughts were , as I sat waiting for events in my chair , without my telling you . Toward four o'clock , strong as I am , fatigue got the better of me . I fell asleep . Not for long . I awoke with a start and looked at my watch .