Driven to Bay, Volume III

‘I suppose you are a detective? ' continued Farrell, after a pause.

‘You are right. I am a private detective, but no one knows the secret but Captain Robarts and yourself, and I should not have confided it to you, except I feel that, for your own sake, you will keep it sacred. And now look here, my boy. I am a man old enough to be your father, and I have had much experience in these cases, with which I have been mixed up all my life. If we are to work together, you must tell me _the truth_. You must hide nothing from me; and you must give me your word of honour not to disclose a single thing that I may say to you.'