Meanwhile, Detective-Sergeant Harborne, following back the clue of the yellow cigarettes, in accordance with the instructions of his superior, who had elected to follow it forward, made his way to a cab-rank at the end of Finchley Road. To a cab-minder he showed a photograph. It was from that unique negative which the Home Secretary had shown to the pseudo-Inspector Sheffield at Womsley Old Place; moreover, it was the only copy which the right honourable gentleman had authorised to be printed. "Does this person often take cabs from this rank, my lad?" The man surveyed it with beer-weakened eyes. "Mr. Sanrack it is, guv'nor! Yes, he's often here!" Harborne, who was a believer in the straightforward British methods, and who scorned alike the unnecessary subtlety of the French school, as represented by Lemage or Duquesne, and the Fenimore-Cooper-like tactics dear to the men of the American agencies, showed his card. "What's his address?" he snapped. "It's farther down on this side; I can't think of the number, sir," replied the other shakily. (The proximity of a police officer always injuriously affected his heart.) "But I can show you the 'ouse." "Come on!" ordered Harborne. "Walk behind me; and when I pass it, whistle." Off went the detective without delay, and walked briskly along the Finchley Road. He had proceeded more than half-way, when, as he came abreast of a gate set in a high wall, from his rear quavered a moist whistle. "70A," he muttered. "Right-oh!" He thrilled with the joy of the chase, anticipating the triumph that awaited him. Inspector Sheffield's pursuit was more than likely to prove futile, but Severac Bablon, he argued, was practically certain to return to his head-quarters sooner or later. He thought of the weeks and months during which they had sought for this very house in vain; of the useless tracking of divers persons known to be acquainted with the man of mystery; of the simple means--the yellow cigarettes--by which, at last, they had come to it. Mr. Aloys. X Alden had been very reticent of late--and Mr. Oppner knew of the cigarette clue. At that reflection the roseate horizon grew darkened by the figure of a triumphant American holding up Severac Bablon with a neat silver-plated model by Smith and Wesson. If Alden should forestall him! Harborne, who had been pursuing these reflections whilst, within sight of No. 70A, he stood slowly loading his pipe, paused, pouch in hand. On one memorable occasion, the super-subtlety of Sheffield (who was tainted with French heresies) had led to a fiasco which had made them the laughing-stock of Scotland Yard. Harborne felt in his breast pocket, where there reposed a copy of the warrant for the arrest of Severac Bablon. And before he withdrew his hand his mind was made up. He was a man of indomitable pluck.