"That is understood," Quarles said. "Let me ask one or two questions, then--rather impertinent ones, but necessary. These stones have been in your family a long while?" "Three hundred years." "They are not often worn, I believe?" "Not often." "And on this particular night you expressed a wish that they should be worn?" "I did." "Quite natural at such an important reception," said Quarles, as though the idea of there being a definite purpose behind the wish had never entered his head. "Lady Leconbridge offered no objection, I presume?" "She preferred the pearls, but she changed them at my request." "You were not in the habit of keeping the jewels at your banker's?" "No; they were kept in a safe in my wife's room." "Rather risky," said Quarles. "To an outsider it seems foolish to keep such jewels constantly in the house, especially when they are so seldom worn. Have you ever contemplated selling the diamonds?" "Never." "Has Lady Leconbridge at any time suggested that you should?" "Certainly not!" "You are prepared to swear that your wife wore this necklace at the Duchess of Exmoor's reception?" said Quarles, holding up the jewels. "I am." "It only shows how risky it is to keep such valuables in the house. These stones are not diamonds, but paste." "What!" Well might Lord Leconbridge start forward and look at the necklace. I did the same myself. "Very well executed, but paste," said Quarles. "Do you suggest----" "Pardon me, I have made no suggestion; I have merely stated a fact." "It isn't true; it's absurd!" "You may prove me right or wrong by showing the stones to an expert. Why not show them to Jacob Hartmann?" "Hartmann! Why to him?" "Because I believe he knows more about precious stones than any man in this country." For the space of a minute Leconbridge and the professor stood looking at each other in silence. "I did not know that," said Leconbridge. "I am a man of the world rather than a detective," said Quarles, his manner suddenly changing, "and to some extent I can appreciate your position. May I become a friendly adviser? Lock this necklace up, and let no one know it has been returned. Take my word for it that the stones are imitation, and leave the matter in my hands. I give you my word that I believe, when the full explanation is forthcoming, you will be perfectly satisfied with it. Will you trust me, Lord Leconbridge?" "Yes," came the firm answer, after a pause. "It will be the work of a few hours, I hope," said Quarles, taking up his hat; "and, of course, it is agreed that the person who returned the jewels is not to suffer." Quarles was thoughtful as we walked away from Hill Street, and well he might be. He had promised a great deal, and how he was going to fulfil that promise was beyond my comprehension. "You expected to surprise Lord Leconbridge into an admission and were disappointed?" I said.