ten o'clock in the morning
But Mr. Mann had another engagement . Moreover , he wanted to think things out . Thinking things out was a process which brought little reward in this instance , and he went to bed that night a vexed and puzzled man . He always had his breakfast in bed at ten o'clock in the morning , for he had reached the age of habits and had fixed ten o'clock , since it gave his clerks time to bring down his personal mail from the office to his private residence . It was a profitable mail , it was an exciting mail , and it contained an element of rich promise , for it included a letter from Constable Wiseman : DEAR SIR : Re our previous conversation , I have just come across one of the photographs of the young lady -- Sergeant Smith 's daughter . It was given to the private detective who was searching for her . It was given to my wife by her cousin , and I send it to you hoping it may be of some use .