Mr. Green turned again, and his shrewd, bright eyes scanned more closely that lean face, whose keenness was all dissembled now in an easy, languid smile. “A bargain?” grumbled the spy. “I' faith, then, the secret's worthless.”

“Ye think that? Pho! 'Tis not like your usual wit, Mr. Green. The letter that I carried into England, and that you were at such splendid pains to find at Maidstone, is in here.” And he tapped the veneered top of the secretaire with his forefinger. “But ye'll not find it without my help. It is concealed as effectively—as effectively as it was upon my person when ye searched me. Now, sir, will ye treat with me? It'll save you a world of labor.”

Mr. Green still looked at him. He licked his lips thoughtfully, cat-like. “What terms d'ye make?” he inquired, but his tone was very cold. His busy brain was endeavoring to conjecture what exactly might be Mr. Caryll's object in this frankness which Mr. Green was not fool enough to believe sincere.

“Ah,” said Mr. Caryll. “That is more the man I know.” He tapped his snuff-box, and in that moment memory rather than inspiration showed him the thing he needed. “Did ye ever see 'The Constant Couple,' Mr. Green?” he inquired.

“'The Constant Couple'?” echoed Mr. Green, and though mystified, he must air his little jest. “I never saw any couple that was constant—leastways, not for long.”

“Ha! Ye're a roguish wag! But 'The Constant Couple' I mean is a play.”

“Oh, a play! Ay, I mind me I saw it some years ago, when 'twas first acted. But what has that to do with—”

“Ye'll understand in a moment,” said Mr. Caryll, with a smile the spy did not relish. “D'ye recall a ruse of Sir Harry Wildairs to rid himself of the company of an intrusive old fool who was not wanted? D'ye remember what 'twas he did?”

Mr. Green, his head slightly on one side, was watching Mr. Caryll very closely, and not without anxiety. “I don't,” said he, and dropped a hand to the pocket where a pistol lay, that he might be prepared for emergencies. “What did he do?”

“I'll show you,” said Mr. Caryll. “He did this.” And with a swift upward movement, he emptied his snuff-box full into the face of Mr. Green.