"Just what I think," returned the senator's son. "Think them fellers set the fire?" asked Mr. Platt, curiously. "We feel certain of it," replied Roger. "They are old school enemies of ours," he added. "It's only one more score we've got to settle with them," he continued, to his chums, and shut his teeth with a snap. Nothing further could be learned concerning the mysterious visitors, and finally the boys went back to the Morr mansion, to get ready for the evening celebration. This came off as scheduled and proved a big success. Fully a hundred town folk were present, besides some from the lake and elsewhere. There were rockets and Roman candles and wheels galore, as well as several set pieces. Some fire balloons were also liberated. Senator Morr had engaged a local band of eight pieces, and if the music was not of a high order it was certainly patriotic, and that counted for a good deal. Of course the other boys had to hear all about the proposed trip West and, incidentally, about the lost Landslide Mine. From his father and mother Roger got some more details concerning the missing property. A map was produced, and also some papers, and the son was advised to hunt up an old miner and prospector named Abe Blower. "Abe Blower knew your Uncle Maurice well," said Mrs. Morr, to her son. "They were friends for years. I am sure if you can find Mr. Blower he will do all he can for you, and for me, too." "Then I'll do what I can to find him, first of all," answered Roger. At last came the time when Dave must leave the Morr home and return to Crumville. He was going alone, but he promised to keep in constant communication with the others. "I wish I was going on that western trip," said Shadow, wistfully. "You'll have barrels of fun, and if you do locate that Landslide Mine--well, it will be a big feather in your cap." "I'd like to go, too," said Buster. "I reckon we'd all like to go," cried the others, in concert. "Well, there is just this much about it," returned Dave. "Anybody who has the price can go on that personally-conducted tour to Yellowstone Park, and, so far as I am concerned, you can go from there into the mountains and look for the mine." "Why, of course!" burst out Roger. "If any of you want to go, just say the word." This brought on a discussion lasting nearly an hour. In the end several of the lads said they would see what they could do, and would write about it later, or telegraph. "Say, but wouldn't it be grand if we could locate that lost mine!" cried Phil, enthusiastically. "Well, we'll have a try at it," returned Dave. At last came the time for Dave to leave. Some of the others had already gone. Roger drove his chum down to the railroad station in the runabout. The two were alone. Dave noticed that the senator's son seemed unusually thoughtful. "What's up, Roger?" he asked, at last. "You don't seem quite like yourself." "Oh, I don't know that I ought to say anything, Dave," was the hesitating answer.