Jim could not imagine why Tom had taken so much trouble to add another room to their house, which was already large enough. But when Tom, having finished the opening upon the inside, went out and began to climb the smaller tree with the help of a few low-growing branches, the youngest member of the expedition became fully convinced in his own mind that the second in command was out of his head entirely. When Tom, having climbed to a height of twelve or fifteen feet, began to chop with his hatchet, Jim remarked, in most emphatic language, that he thought “a fellow who would chop at a sycamore tree just for the sake of making chips, when he might be eating his supper, was too big a fool to live.” Tom did not respond to Jim’s sarcasm, but persevered in his chopping until he had made an opening at the point to which he had climbed. Balser had quickly guessed the object of Tom’s mighty labors, but he did not enlighten Jim. He had gone to other work, and by the time Tom had made the opening from the outside of the smaller tree, had collected a pile of firewood, and had carried several loads of it into the castle. Then Tom came down, and Jim quickly followed him into the large tree, for by that time his mysterious movements were full of interest to the little fellow. Now what do you suppose was Tom’s object in wasting so much time and energy with his axe and hatchet? A fireplace. You will at once understand that the opening which Tom had cut in the tree at the height of twelve or fifteen feet was for the purpose of making a chimney through which the smoke might escape. The boys kindled a fire, and in a few minutes there was a cheery blaze in their fireplace that lighted up the room and made “everything look just like home,” Jim said. Then Jim went outside and gave a great hurrah of delight when he saw the smoke issuing from the chimney that ingenious Tom had made with his hatchet. [Illustration: THE CASTLE ON THE BRANDYWINE.] Jim watched the smoke for a few moments, and then walked around the tree to survey the premises. The result of his survey was the discovery of a hollow in the third tree of their castle, and when he informed Balser and Tom of the important fact, it was agreed that the room which Jim had found should be prepared for Tige and Prince. The dogs were not fastidious, and a sleeping-place was soon made for them entirely to their satisfaction. Meantime the fire was blazing and crackling in the fireplace, and the boys began to prepare supper. They had not had time to kill game, so they fried a few pieces of bacon and a dozen eggs, of which they had brought a good supply, and roasted a few sweet potatoes in the ashes. Then they made an opening in the ice, from which they drew a bucketful of sparkling ice water, and when all was ready they sat down to supper, served with the rarest of all dressings, appetite sauce, and at least one of the party, Jim, was happy as a boy could be. The dogs then received their supper of bear meat.