"How did the stuff get here?" asked Dan wonderingly. Dick was now at the edge of the ice pile, and flashed the light at the roof of the cavern. "See the rifts in the rock up there?" he asked. "Water must have leaked in here during the heavy winter rains. It was cold water, too. Then, in extra cold spells, such as this country experiences, the water must have frozen. As heat doesn't get in here in warm weather the ice may have been here for generations. Fellows, we may be looking upon ice that was here when George Washington was a boy." "I've read, somewhere," declared Tom soberly, "that icebergs that float down from the polar regions in spring often represent ice that is at least ten thousand years old. Fellows, some of this very ice may have been here in this cave long, long before Julius Caesar went into the soldiering business!" That thought had somewhat of an awesome effect upon Dick & Co. The four high school boys felt as though they were in the presence of great antiquity. "But the practical side of it," declared Tom, "is that we must devise the best way of cutting some of this ice and getting it across the lake to the camp." "Oh, you can break off enough for making ice water," replied Dave Darrin impatiently, "and take it over in the canoe, though the spring water is cold enough for anybody." "All of Dave's thoughts are still on the man of mystery," Dick declared, with a chuckle. "It's much more interesting than standing here figuring on how to get ice that we don't need," retorted Darry. "Now, as to moving this stuff to the camp," Tom went on, "it seems to me-----" "Of course," laughed Dick. "It has already struck you that we can fell a few small trees and build a raft on which we can tow a few hundred pounds of ice at a time." "Oh, pshaw!" fidgeted Dave. "I am anxious to find the man of mystery." "That isn't anything practical," scoffed Tom Reade, "while in hot weather a good supply of ice is eminently practical." "You'll think there's a practical side to the man of mystery and his cronies when to-night comes, and there's so much noise about the camp that we miss another night's rest," hinted Darry sagely. "Humph!" was Tom's greeting to that assertion. "I don't know but you're right." "Well, we know where the ice is," remarked Dick. "We can get it at our convenience. Darry, we'll follow you in pursuit of your man of mystery. Come out of here, fellows." Dick led the way out of the cave, flashing the light as he walked. All four blinked when they found themselves out in the sunlight. "Now, which way are we going, David, little giant?" demanded Tom good-humoredly. Now that he was put to it, Dave had to confess that he didn't know. "Let's make a swift, thorough search all around here, and see if we can find any footprints not made by ourselves," Dave suggested rather weakly, at last.