He passed it to Mr. Baker, and, from where he stood Roy could see the swindler slip it into his pocket and substitute for it one somewhat like it, but, probably made of brass instead of gold. Mr. Baker turned his back, pretending to be trying to get a good light, while he compared his watch with that of Mr. De Royster. "That's a fine diamond pin in your tie," said Tupper, indicating the stone in the salesman's tie. "Yes. Would you like to look at it? It is of very pure color." He drew out the gem, and, unsuspectingly passed it to Tupper. At that instant the locomotive engineer blew two warning whistles, so that the lagging passengers might get on the train, which was about to start. "Hurry up! All aboard!" exclaimed Hynard, and, as Roy watched, he saw Tupper thrust Mr. De Royster's diamond into his own pocket. "They're robbing him!" thought the boy from the ranch. "I must warn him!" He started forward. Mortimer De Royster grabbed up his suit-case and started for the train. Then he became aware that Mr. Baker had not handed him back his watch, while the other man had his pin. "My timepiece!" he exclaimed. "I'll show it to you when we get in the train. I assure you it's a very fine one. And my pin--I would not like to lose it! Give them back!" Hardly had he spoken when Hynard thrust his hand down into the inside pocket of Mr. De Royster's coat. His object was to grab his pocketbook, the bulging outline of which he had seen. "Look out!" cried Roy in a loud voice, springing from his hiding place. "Look out! They're swindlers! They've got your watch and pin, and they're trying to get your money!" [Illustration: "Look out," cried Roy, "they are swindlers!"] "There's that boy!" exclaimed Hynard, as he drew out his hand. But Mr. De Royster had felt the sneaking fingers, and had made a grab for them. He was too late, however, and, in attempting to catch Hynard he stumbled and fell. "Come on!" cried Baker to his companions. "Let him go! We've got the stuff." "Grab them!" cried Roy to De Royster. "I'll help you." He rushed forward. No sooner did the swindlers see him coming, than they changed their plans. They had intended jumping on the train, which was already in motion, and leaving Mr. De Royster behind, after they had his watch and diamond. But Roy's quickness prevented this. Baker signalled to his companions, and they ran off down the track. "Come on!" cried Roy. "We'll catch them!" "No! I must go to New York," replied the salesman as he arose, and brushed off his clothes. "The train is going." "But they've got your valuables!" "I know it. I was a fool, but it's too late now. Help me aboard." The train was gathering headway. Roy ceased his pursuit of the robbers and helped De Royster aboard, the young man carrying his dress-suit case. Then Roy followed, while the four swindlers kept on down the railroad tracks. CHAPTER X ROY GAINS A FRIEND