n some
outward bound vessel. Crews will not be scrutinised so sharply as
passengers. There are those who will let you know my movements. Fear the
police may tamper with your correspondence, but later on when hue and
cry has died down will let you know all.'"

The two detectives looked at each other.

"A barge below Tower Bridge," repeated Green, with something like
admiration. "That was a good shot. He might have stayed there till
doomsday without our hitting on him, or any one taking any notice of
him."

"I don't know," said Foyle. "A newcomer on the river would attract
attention. These water-men know each other. There's only one way that I
can see in which he would avoid being talked about. He is a watchman."

"You're right, sir," agreed the other emphatically. "This is a matter
where Wrington of the Thames Division will be able to help us. Hope we
can find him at Wapping. Shall I ring through?"

"There's no hurry for a minute or two," said Foyle. "Let's get the hang
of the thing right. There's probably some hundreds of barges below Tower
Bridge. It will be as well to keep a close eye on the docks and shipping
offices. You see, he asserts his innocence."

"H'm," commented Green, with an intonation that meant much. "He says,
too, that there are reasons why he shouldn't be questioned."

"Well, we shall see. There had better be an all-station message about
the docks. Send two or three men down to Tilbury to watch outgoing boats
there. We shan't need any other men from here. Wrington's staff know the
river, and will get on best with them. I don't want to leave here until
Blake lets us know more about the woman who left the advertisement. That
gives us another possible clue."

It was some time before Wrington, the divisional detective-inspector at
the head of the detective staff of the Thames Division, could be found,
for like other branches of the C.I.D. he and his men did their work
systematically, and usually left their office at nine o'clock only to
return at six. At length, however, he was found at a wharfinger's
office, where there had arisen some question of a missing case of
condensed milk. Within half an hour he was at Scotland Yard.

A tall man with tired grey eyes, about the corners of which were tiny
wrinkles, with a weather-beaten face and grey moustache, he aimed to
look something like a riverside tradesman. There was a meekness in his
manner and speech that deceived people who did not know his repu