Van Sneck looked up with some signs of confusion. He had not expected a question of that kind. There was just the suggestion of cunning on his face.
"A ring!" he murmured, vaguely. "A ring! What ring?"
"Now, look here," David said, sternly. "You are more or less in our power, you know, but we are not disposed to be hard on you so long as you are quite candid with us. Henson required something that he believed to be in your possession; indeed, you have as good as said you had it with you. Henson lured you into my house to get that more than anything else. That he would have killed you even after he got it, I firmly believe. But that is not the point. Now, was not Henson looking for Prince Rupert's ring that you got from him by means of a trick?"
Van Sneck dropped his hands helplessly on the bed.
"Gentlemen," he whined, "you are too much for me. The marvellous accuracy of your knowledge is absolutely overwhelming. It was the ring Henson was after."
"The one you stole from him years ago! But what did you know about it?"
Van Sneck smiled.
"There is no living man who knows more about those things than I do," he said. "It is a passion and a study with me. And some seven years ago, in Holland, Henson gave me the description of a ring he wanted me to copy. Henson never told me what the ring was called, but I knew it was the Prince Rupert ring. I made the copy, and Henson was pleased with it. Some time later he came to me with the original, and asked for another copy. I meant to be honest, but my love for those things got the better of me. I made him two copies: the one good, and the other an exact facsimile of the Prince Rupert. These I handed over to Henson, and he went away perfectly satisfied that he had a good copy and the original. I chuckled to myself, feeling pretty sure that he would never find out."
"But he did find out?" David said.
"Only lately. Probably he took it to an expert for valuation or perhaps for sale. Lately his idea was to offer the ring to Lord Littimer for a huge sum of money, but when he discovered he had been done he knew that Lord Littimer would not be so deceived. Also he had a pretty good idea that I should keep the ring about me. You see, I dared not sell an historic gem like that. And, as usual, Henson was perfectly right."