eleven o'clock
`` Oh , the cab , '' groaned Löwe -- `` that clue failed . The police must have mistaken the number . They telephoned immediately to all the police stations , and a watch was set , with the result that number 72,863 was stopped as it was going home for the night . But it then turned out that the cab had not been off the rank since eleven o'clock , and the driver had been in the shelter all the time with several other men . But there is a clue ; I have it here . '' Mr. Löwe 's face brightened for once as he reached out for the bandbox . `` The houses in Howard Street , '' he explained , as he untied the fastening , `` have small balconies to the first-floor windows at the back .