This series of books for wide-awake American lads was begun several years ago with the publication of "The Rover Boys at School." At that time the author had in mind to write not more than three volumes, relating the adventures of Dick, Tom, and Sam Rover at Putnam Hall, "On the Ocean," and "In the Jungle," but the publication of these books immediately called for a fourth, "The Rover Boys Out West," and then a fifth, "The Rover Boys on the Great Lakes." Still my young friends did not appear to be satisfied, and so I now present to them this sixth volume, which relates the stirring adventures of the three Rover boys in the Adirondacks, whither they had gone to solve the mystery of a certain brass-lined money casket found by them on an island in Lake Huron. In writing this volume I have had a double purpose in view; not only to pen a tale which might prove pleasing to all boys, but one which might likewise give them a fair idea of the wonderful resources and natural beauty of this section of the United States. Ours is a wonderful country, and none of us can learn too much concerning it. Again thanking my young friends for their kindness in the past, I place this volume in their hands, trusting they will find it as much to their liking as those which have preceded it. Affectionately and sincerely yours, ARTHUR M. WINFIELD. THE ROVER BOYS IN THE MOUNTAINS. CHAPTER I. THE BOYS OF PUTNAM HALL. "Hurrah, boys, the lake is frozen over! We'll be sure to have good skating by to-morrow afternoon!" "That's fine news, Tom," came from Sam Rover. "I've been fairly aching for a skate ever since that cold snap of two weeks ago." "We'll have to start up some skating matches if good skating does really turn up," put in Dick Rover, who had just joined his two brothers in the gymnasium attached to Putnam Hall. "Don't you remember those matches we had last year?" "Certainly, Dick," answered Tom Rover. "Didn't I win one of the silver medals?" "Gracious! but what a lot has happened since then," said Sam, who was the youngest of the trio. "We've gotten rid of nearly all of our enemies, and old Crabtree is in jail and can't bother Mrs. Stanhope or Dora any more." "We didn't get rid of Dan Baxter," remarked Dick. "He gave us the slip nicely." "Do you think he'll dare to bother us again, Dick?" questioned Sam anxiously. "I hope not, but I'm not certain, Sam. The Baxters are a bad lot, as all of us know, and as Dan grows older he'll be just as wicked as his father, and maybe worse." "What a pity a fellow like Dan can't turn over a new leaf," came from Tom Rover. "He's bright enough in his way, and would make a first-rate chap." "It's not in the blood," went on Dick. "We'll have to keep our eyes open, that's all. If anything, Dan is probably more angry at us than ever, for he believes we were the sole means of his father being put in prison." "Old Baxter deserved all he got," murmured Sam. "So he did."