ed him where he lived, and as the result I
have jotted down the address in my note-book." Gaultier searched through
his memoranda, and speedily found what he wanted.

"Wait a minute," interrupted Brett. "Does it happen to be No. 11, Rue
Barbette?"

The barrister had more than once surprised his companion during the
previous night, but this time Gaultier seemed to be more annoyed than
startled.

"If you know all these things," he said stiffly, "I don't see why you
should bother me to get you the information. I certainly gathered from
your remarks that the only acquaintance you had with Hussein-ul-Mulk was
obtained from the newspapers, and that individual himself has the best
of reasons for not publishing his address broadcast."

Brett smiled.

"You mean," he said, "that Hussein-ul-Mulk does live at No. 11, Rue
Barbette."

"Why, of course he does," was the irritable answer.

"That is very odd," said the barrister. "It was a mere guess on my part,
I assure you."

His assurance evidently did not weigh much with Captain Gaultier, who
replaced the note-book in his pocket, and obviously cast about in his
mind for a convenient excuse to take his departure.

Brett knew exactly what was troubling him.

"I am quite in earnest," he said, "in telling you that I simply hazarded
a guess at the address. To prove that this is so, I must place you in
possession of certain incidents which took place after we parted at the
Gare du Nord."

Rapidly but succinctly he told the amazed King's messenger of the chase
in the cab across Paris, and how he (Brett) had followed the Frenchman
who was tracking Gaultier's movements so closely.

"You will understand," he concluded, "that, in view of my preconceived
theory, it was not a very far-fetched assumption to connect
Hussein-ul-Mulk with the house in the Rue Barbette into which your spy
vanished."

"Well," gasped his astonished hearer, "I must say, Mr. Brett, that I owe
you an apology. I really thought at first you were fooling me, whereas
now I learn that you simply kept your eyes open much wider than other
people, perhaps. Nevertheless, you have given me a genuine explanation
of circumstances that were otherwise puzzling. For, do you know, I heard
about that chap calling at the Embassy last night. The incident was
unusual, to say the least, but I paid little attention to it, and
certainly failed altogether to connect it with your visit to Paris. Even
yet I do not see what reason