The ring at the bell proved to be something even more satisfactory than an answer, however, for the door opened and a rough-looking fellow entered who was evidently the man himself.

I got a message from the head office that a gent at this address had been inquiring for 2704, said he. I've driven my cab this seven years and never a word of complaint. I came here straight from the Yard to ask you to your face what you had against me.

I have nothing in the world against you, my good man, said Holmes. On the contrary, I have half a sovereign for you if you will give me a clear answer to my questions.

Well, I've had a good day and no mistake, said the cabman, with a grin. What was it you wanted to ask, sir?

First of all your name and address, in case I want you again.

John Clayton, 3 Turpey Street, the Borough. My cab is out of Shipley's Yard, near Waterloo Station.

Sherlock Holmes made a note of it.

Now, Clayton, tell me all about the fare who came and watched this house at ten o'clock this morning and afterwards followed the two gentlemen down Regent Street.

The man looked surprised and a little embarrassed. Why, there's no good my telling you things, for you seem to know as much as I do already, said he. The truth is that the gentleman told me that he was a detective and that I was to say nothing about him to anyone.

My good fellow, this is a very serious business, and you may find yourself in a pretty bad position if you try to hide anything