"Sure," replied Mr O'Donovon, after reading the duplicate message. "It was a boy of twelve or about. Black hair and eyes and a Jewish nose. He had a mole on his chin. I remember he gave me two pound notes and I gave him half a crown change."

"I suppose by no possibility could you show me the notes? inquired Entwistle.

"No, sir," replied Mr. O'Donovon. "That I can't. We put all notes into a drawer. I call to mind that they were rather dirty, although it's dirtier ones I've seen in Dublin."

"I thought not," remarked Entwistle. "Perhaps it's as well, for in all probability you gave the lad half a crown for sending the cablegram. If you've time you might examine the notes in that drawer. Ten to one, you'll find two were printed in Germany. Now, will you please send me a priority telegram—on H.M.S.—to Leith, Auldhaig, and Wick; the latter to be transmitted by wireless to Commander-in-Chief, Grand Fleet, Scapa Flow."

Having done all that he could possibly do to scotch von Preussen's activities on the Continental cables, Entwistle prepared to follow up the clues that would, he hoped, lead to the running to earth of the cunning and resourceful spy.

His next step was to trace the boy with the Jewish features and the mole on his chin. It was rather a tall undertaking, for, in spite of the fact that there was a hideous massacre of Jews in York in the remote days when Richard Coeur de Lion reigned, there seemed to be a distinct predilection on the part of people of Hebraic origin to live in the city that holds the position of capital of the Shire of Broad Acres. Besides, many people have moles on their faces, and O'Donovon might have been slightly wide of the mark in describing the mole as being on the lad's chin. It might have been his cheek—either his left or his right.

It was in Petergate, one of those narrow, old-world thoroughfares leading to the Cathedral precincts that Entwistle came face to face with the immediate object of his investigations. Sauntering towards him was a young Jewish lad with a mole on the point of his chin.

Entwistle gave him no opening.

"I say, my lad," he exclaimed, holding out a bright half-crown to the astonished youth, "I gave you the wrong change when you handed in that telegram from Grabnut & Plywrench. Here you are."

The boy took the proffered coin eagerly. As Entwistle expected, he devoted more attention to the coin than he did to the donor.