How long these invaluable shrieks and moans might be counted upon to continue became a vital question. Could they only last till a boat could be completed, launched, provisioned, and directed away to a safer retreat, he would ask for nothing more. He returned again to an inspection of the "map"--now singularly plain. The island was graphically represented by the three conventional "hills," with the sign for water inscribed at either end. The tree, so conspicuous upon the tallest wall of rock, was no less vividly portrayed. Below this identifying picture of the place the hill with the tree was repeated, with the cave and design for water, while just to the right the detail of the cavern, with more water signs, indicating both high and low tide, was depicted somewhat enlarged. The cartouch was not so readily comprehended. Grenville was inclined to believe it spelled some crude king's name, while the scarab, or beetle, was, of course, an old Egyptian symbol concerned with life and death. It would hardly have been human of Grenville not to wonder about the cave or to contemplate a visit there--just to have the merest look about the place. He even went so far as to wonder if its entrance might not be effected from the upper brink, by means of a longer rope ladder than the one he had already made. He did not, however, seriously contemplate delaying affairs more important to gratify this whim. Indeed, he was fired with new impatience to work night and day against the hour of escape. The thought put him back on his feet, then and there, with the documents stored away. There was no time to lose--not a moment--not even to fool with the tiger! He left his bomb and its fuse upon the rocks, and carried the water to his clay. To line his hollow-tree furnace as promptly as possible must be his first concern. No boat could be made without suitable tools, and---- He wondered how he should make it, even then. The log he had found on the day they arrived was such a huge affair to attack with the implements his limited craft made possible, despite all the bronze he could melt. And yet, without it, he was helpless. The raft was far too clumsy for propulsion. It afforded practically nothing transformable into a boat, as he had no nails, no saw, no anything with which it might be first dismembered, and finally reconstructed. "By Jove!" he exclaimed to himself, aloud, as a new thought crept subtly to his brain. "I can hollow the log with fire!" He went at once to the straight and ample tree-trunk, lying propped upon a rock. Its ends had already been partially consumed, and thereby rounded, in the flames that had ravaged the place. How he could cover such parts as he must not burn with a plaster of his clay, Grenville instantly conceived. And there was the log already lifted away from the earth, for the fire to be kindled beneath!