All that day the two boys tramped about the mine, part of the time in company and at other times pursuing their investigations separately. They talked with the men, working in various subtle ways to obtain hints that might start them in the right direction. Night came, but when they compared notes they found that they had made no progress. "I would go back to-night," said Steve thoughtfully, "but to do so would attract attention. They know we do not work at night and someone might become suspicious." The next day was a repetition of the previous one so far as results were concerned. Not a clue did either boy find. This went on for three days, during which time they had not seen Mr. Penton. He was giving his two track inspectors a clear field, unhampered by any directions from him, and this put them on their mettle, perhaps more keenly than would otherwise have been the case. "To-morrow will be Saturday. Don't you think it would be a good time for us to camp on the trail steadily?" asked Jarvis on Friday night as they were going home. "I have been thinking of that. I'll tell you what I want you to do to-morrow. Go to the pay clerk and time checker and find out who is left in the mine after all hands who are going to do so have checked in and drawn their wages. When you get the list bring it below to me. I will meet you somewhere near the chutes on seventeen. I want only the names of those who belong on the shift working Saturday afternoon. There will not be many of them." Jarvis carried out his instructions and brought the list to Rush on the following day. The two boys scanned the list keenly, after which they made tours of the working drifts, finding all the men at their stations and no one in the mine who did not belong there. "I'm coming back to-night," decided Steve with emphasis. "I am satisfied that the people we are looking for are not on the day shift. We will come down about eight o'clock, by way of the ladders, and prowl quietly about. We will use our candles only when we get in drifts where there is no one at work." "We won't catch anyone. They're too sharp for us." "Perhaps not to-night, but we'll get them if it takes a year to do it. I'll never give up till I have won this game of hide and seek. When you go after a thing, Bob, make up your mind you're going to get it. You'll land somewhere near the mark if you follow that policy." "I've got the dynamite report here for you."