By a certain gnarled chestnut which overhung the cliff above them, growing out of the hill near the spring, they estimated the length of the subterraneous passage to be not less than a quarter of a mile. The sun, which had broken through the clouds, indicated by the angle of his rays that the afternoon was well past. They now thought it advisable to retrace their steps through the unsavory cavern. In view of the stifling passage, Coleman inhaled deep drafts of the sweet outer air, and shuddered involuntarily at the necessity of repeating the experience, even when he knew the animal now following him was only stupid old Tumbler. George handed him a piece of the mica to carry, and his careless, happy mood indicated that he returned to the subterraneous passage as gaily as if it were a pleasant walk overland. As they drew near the entrance to the cavern, with the bear shambling at their heels, an indefinable dread of trouble ahead took possession of Coleman. It might have been the absence of the resinous smell of the torches. At all events, they were presently standing in the gruesome half-light before the empty crevice, through which they could see their pine-knots still burning fifty feet below in an inner cavern. As their torches had burned to the edge of the rock they had fallen through the opening. They were without fire, and if they should succeed in striking it with their flints, they had no means of carrying it a hundred yards into the darkness. The situation was frightful. Outside, the perpendicular cliff rose a matter of sixty feet to the overhanging trees of the plateau, and close to the south ledge, which towered above it. The two men and the bear were prisoners on this barren shelf of rocks, with a quarter of a mile of subterraneous darkness separating them from food and shelter--from life itself. Was it their destiny, Coleman thought, to die of starvation among these inhospitable rocks, hung like a speck between the plateau and the valley, watched by the circling eagles and by the patient buzzards, who would perch on the nearer tree-tops to await their dissolution? The very thought of the situation unmanned him. [Illustration: EXPLORING THE CAVE OF THE BATS.] Lieutenant Coleman was not a man to shrink from enemies whom he could see; but the darkness and the dangers of the half-explored cavern terrified him. Corporal Bromley, on the other hand, was only made angry by the loss of the torches; and the livid expression of his face reminded his comrade of the morning when they had received the news of General Sherman's death before the works at Atlanta. In a moment, however, he was calm. Without a word, he walked away among the rocks, and when he came back he held in his hands a lithe pole ten or twelve feet long. "Not a very interesting outlook, Fred, for a man who would rather be eating his supper," said George, trying the strength of his pole; "but you must be patient and amuse yourself as best you can."