"Why especially to-morrow?" asked Bob. "Fire dies in the cool of night; it comes up in the middle of the day," explained Morton succinctly. Bob took to the right, while Jack went in the opposite direction. His way led down hill. He crossed a ravine, surmounted a little ridge. Now he was in the worse than total darkness of the almost extinct area. Embers and coals burned all over the side hill like so many evil winking eyes. Far ahead, down the mountain, the rising smoke glowed incandescent with the light of an invisible fire beneath, Bob, blinded by this glow, had great difficulty in making his way. Once he found that he had somehow crept out on the great bald roundness of a granite dome, and had to retrace his steps. Twice he lost his footing utterly, but fortunately fell but a short distance. At last he found himself in the V of a narrow ravine. All this time he had, with one exception, kept close track of the fire line. The exception was when he strayed out over the dome; but that was natural, for the dome had been adopted bodily as part of the system of defence. Everywhere the edge of the path proved to be black and dead. No living fire glowed within striking distance of the inflammable material on the hither side the path. But here, in the bottom of the ravine, a single coal had lodged, and had already started into flame the dry small brush. It had fallen originally from an oak fully a hundred feet away; and in some mysterious manner had found a path to this hidden pocket. The circumstances somewhat shook Bob's faith in the apparent safety of the country he had just traversed. However, there were the tiny flames, licking here and there, insignificant, but nevertheless dangerous. Bob carefully laid his canteens and the rake on a boulder, and set to work with his sharpened hoe. It looked to be a very easy task to dig out a path around this little fire. In the course of the miniature fight he learned considerable of the ways of fire. The brush proved unexpectedly difficult. It would not stand up to the force of his stroke, but bent away. The tarweed, especially, was stubborn under even the most vigorous wielding of his sharpened hoe.