said that he was
a detective, and he offered me two guineas if I would do exactly what he
wanted all day and ask no questions. I was glad enough to agree. First
we drove down to the Northumberland Hotel and waited there until two
gentlemen came out and took a cab from the rank. We followed their cab
until it pulled up somewhere near here."

"This very door," said Holmes.

"Well, I couldn't be sure of that, but I dare say my fare knew all about
it. We pulled up halfway down the street and waited an hour and a half.
Then the two gentlemen passed us, walking, and we followed down Baker
Street and along--"

"I know," said Holmes.

"Until we got three-quarters down Regent Street. Then my gentleman threw
up the trap, and he cried that I should drive right away to Waterloo
Station as hard as I could go. I whipped up the mare and we were there
under the ten minutes. Then he paid up his two guineas, like a good one,
and away he went into the station. Only just as he was leaving he turned
round and he said: 'It might interest you to know that you have been
driving Mr. Sherlock Holmes.' That's how I come to know the name."

"I see. And you saw no more of him?"

"Not after he went into the station."

"And how would you describe Mr. Sherlock Holmes?"

The cabman scratched his head. "Well, he wasn't altogether such an easy
gentleman to describe. I'd put him at forty years of age, and he was
of a middle height, two or three inches shorter than you, sir. He was
dressed like a toff, and he had a black beard, cut square at the end,
and a pale face. I don't know as I could say more than that."

"Colour of his eyes?"

"No, I can't say that."

"Nothing more that you can remember?"

"No, sir; nothing."

"Well, then, here is your half-sovereign. There's another one waiting
for you if you can bring any more information. Good-night!"

"Good-night, sir, and thank you!"

John Clayton departed chuckling, and Holmes turned to me with a shrug of
his shoulders and a rueful smile.

"Snap goes our third thread, and we end where we began," said he. "The
cunning rascal! He knew our number, knew that Sir Henry Baskerville had
consulted me, spotted who I was in Regent Street, conjectured that I had
got the number of the cab and would lay my hands on the driver, and so
sent back this audacious message. I tell you, Watson, this time we have
got a foeman who is worthy of our steel. I've been checkmated in London.
I can only wish you bett