one o'clock
And he means it . '' He turned the folded sheet over and saw on the addressed side of it the postmark Hintondean , and the prosaic detail `` 2d . to pay . '' He got up slowly , leaving his lunch unfinished -- the letter had come by the one o'clock post -- and went into his study . He rang for his housekeeper , and told her to go round the house at once , examine all the fastenings of the windows , and close all the shutters . He closed the shutters of his study himself . From a locked drawer in his bedroom he took a little revolver , examined it carefully , and put it into the pocket of his lounge jacket .