The Beau held out his hand. It was shaking a little. He said: “Thank you. That is mine.”

The stranger looked rather doubtfully at him. “Yours, is it, sir? Well, if you say so, I’m sure it is so, but maybe I’d best give it to the landlord—not meaning any offence, your Honour, but seeing as it’s a valuable kind of a trinket, and me having found it.”

A fixed smile was on the Beau’s lips. He said: “Quite unnecessary, I assure you. You will perceive that it is of unusual design. I could not mistake it.”

The stranger turned it over in his hand. “Well, of course, sir, if you say so—” he began undecidedly.

“My good fellow,” interrupted the Beau. “You must have seen me look for something upon the mantelshelf a minute ago. Your scruples are quite absurd, believe me. Anyone will tell you that that glass belongs to me. Be good enough to give it to me, if you please.”

“Oh yes, certainly that is Mr Lavenham’s quizzing-glass!” said Miss Thane. “There can be no doubt!”

The stranger advanced, holding the glass out to the Beau. He grasped it, and in that instant a suspicion of the trap into which he had walked seemed to flash before his brain, and he sprang back, glaring at the man before him.

“Then, in the name of the Law I arrest you, Basil Lavenham, for the wilful murder of Matthew John Plunkett!” said the stranger.

Before he had finished speaking the Beau had whipped a pistol from his pocket and levelled it. The smile on his lips had become a ghastly grimace, but it still lingered. He said, quick and low: “Stand where you are! If you move you are a dead man!” and began to back towards the door.

The Bow Street Runner stood still perforce. Miss Thane, standing a little behind the Beau, perceived that the moment for a display of heroism had arrived, and in one swift movement got between the Beau and the door. In the same instant Eustacie shrieked: “Nye! A moi! ”