one o'clock in the morning
The momentary flare disclosed a square envelope standing on edge and close in against the seat . Extinguishing the match , he caught it up . It was of white linen of superior quality , without superscription , and sealed ; the contents were very light -- a single sheet of paper , likely . The handkerchief , the crushed roses , the unaddressed , sealed envelope -- the horse , the empty and deserted cab , standing before a vacant lot , at one o'clock in the morning ! Surely any one of them was enough to stir the imagination ; together they were a tantalizing mystery , calling for solution and beckoning one on . Harleston took another look around , saw no one , and calmly pocketed the envelope . Then , after noting the number of the cab , No. 333 , he gathered up the lines , whipped the ends about the box , and chirped to the horse to proceed .