the hour of two
I agreed at once , and started off . Thus a second time my plans were interrupted , for my expedition that night ultimately led me to Bow Street , whence , after certain formalities had been observed , I departed for my chambers , the mysterious pigtail in my pocket . Failing the presence of Durham , the pigtail must have been retained as evidence , but : `` We shall know where to find it if it 's wanted , Mr. Knox , '' said the Yard man , `` and I can trust you to look after your own property . '' The clock of St. Paul 's was chiming the hour of two when I locked the door of my chambers and prepared to turn in . The clangour of the final strokes yet vibrated through the night 's silence when someone set my own door bell loudly ringing . With an exclamation of annoyance I shot back the bolts and threw open the door . A Chinaman stood outside upon the mat !