Then the truth came to his bright mind like a flash of inspiration. The missing diamond had been stuck in the gum. Still that didn't explain to his mind how the diamond had got there, or how the lady who had been in the store half an hour after the man had come in possession of the diamond. The matter puzzled him greatly, but of one thing he was confident, and that was that the missing diamond was now in the man's pocket. Under such circumstances he believed that it was his duty to follow the pair. The couple turned into Nassau street and walked leisurely northward. Dick kept on behind them in a rather doubtful frame of mind. They kept straight on, passing the Tribune Building and the other newspaper offices of the Row, and so on under the Brooklyn Bridge entrance to the corner of North William, a narrow and short street that cuts into Park Row at that point. They crossed the head of this street and walked into a well-known pawnshop that stood there. "I'll bet the man is going to pawn that diamond," thought Dick. "Well, I'm going to see if he is." He immediately followed them into the public room. He found them standing before the long counter. A clerk came up to them. "How much will you advance me for a month on that diamond?" asked the man, taking the unset stone out of his pocket and laying it down on the counter. The size of the diamond corresponded with the missing one, and on the spur of the moment Dick glided to the counter and grabbed it before the clerk's fingers touched it. "I don't think this shop will advance you a dollar on a stolen diamond," he said, stepping back defiantly, ready to maintain his employer's claim to the stone. The woman gave a stifled exclamation and looked frightened. "Give me that diamond!" cried the man. "No, sir. Will you send for a policeman to settle this matter?" said Dick to the clerk. "Do you want me to send for an officer?" the clerk asked the man. "No; I can settle my own business without a cop butting into it," replied the man savagely. "Call an officer for me, then," said Dick. "I accuse this man of stealing the diamond he asked you to fix a price on." "How dare you call me a thief!" roared the man. "Because that's what you are," answered Dick defiantly. Customers coming into the pawnshop stopped to see what was going on. As the case stood, all the advantage lay with Dick, for he had the article in dispute, and possession is nine points of the law. As the racket was highly undesirable in the pawnshop, the clerk decided to telephone for a policeman to come and straighten things out, since neither Dick nor the man showed any signs of giving in. The man himself realized that things were growing desperate. The lady said something to him in a low tone, but he shook his head impatiently. Evidently somebody had told a policeman of the case, for just at this time an officer appeared. CHAPTER V.--Dick Carries His Point. "Well, what's the trouble here?" asked the officer.