"Yes; there'll be trouble enough when we find out where it is--trouble for the fellow or fellows who are to blame for it," answered the mine captain. "Well, keep your eyes open. If you need any help, let me know." "I've had the inspectors on the job for a week now, and they are no nearer solving the mystery than they were before they began." Mr. Penton was watching Steve at work with a thoughtful expression in his eyes. "That's a promising boy, Jim," he said. "You mean young Rush?" "Yes. This is the kind of job I should like to turn him loose on, if he had more experience. He's as sharp as a steel trap." "That is true." "He has that dogged persistence that would make him hang on like a bull terrier. I'm going to push him along as fast as seems advisable." "He's a likely youngster," admitted the mine captain, studying Steve's back as the lad swung his iron bar with unerring precision. "Yes, he's a very likely lad." "I want to make an inspection of number twelve," said the superintendent, rising. "Will you come along?" The captain followed his superior officer, the two men soon disappearing down the level. Steve watched their bobbing candles until he could see them no longer. "Something is going on here," muttered the boy. "Reports show more ore taken out than has really been mined. I didn't want to listen, but I couldn't help hearing what they said." For the rest of the forenoon Steve occupied his leisure moments in trying to study out how such a mistake could occur. He was not thoroughly familiar with the working of the system as yet, but he possessed a good general idea of the methods employed to protect the company against mistakes and dishonesty. The time-keepers made their rounds four times a day, and any man not at his post lost his time until the next round. The ore was tallied at the chutes and weighed again after it had been placed on railroad cars for transportation to the Great Lakes. All this Steve went over, his mind working actively on the subject while his hands were busy dumping cars of ore. "The mistake, if it is a mistake, must occur somewhere between this chute and the freight yards," was the lad's mental conclusion. In this he was right. So full of his subject was he that, when the whistle blew, he sat down on the bench that the superintendent had occupied a few hours before and studied the tally-boards as he ate his lunch. The manner of the tally operation was clear to him. There was nothing complicated about it. Having finished his lunch, the lad strolled over to the tally-boards, and, with hands behind his back, began studying the names of the drifts or contractors represented there. Spooner's was the first to attract his attention. "I'll bet I have shoveled that board full half a dozen times," muttered the lad, with a grin. "What do you want here?" demanded a surly voice at the lad's elbow. Rush turned and found himself facing the tally-man, Marvin.