The fire's mounting course was paralleling the trail; checked from crossing it only by a streambed and an outcrop of granite which zigzagged upward from the valley. The darkness served also to tinge the lowering sky to south and to westward with a steadily brightening lurid glare. The Master had been right in his glum prophecy that a strong and sudden shift of wind would carry the conflagration through the tinder-dry undergrowth and dead trees of that side of the mountain, far faster than any body of fire-fighters could hope to check it. The flame-reflection began to light the open spaces below the knoll, with increasing vividness. The chill of early evening was counteracted waves of sullen heat, which the wind sent swirling before it. Lad panted; from warmth as much as from nervousness. He had gone all day without water. And a collie, more perhaps than any other dog, needs plenty of fresh, cool water to drink; at any and all times. The hot wind and the smoke were parching his throat. His thirst was intolerable. Behind him, not very many yards away, was the ice-cold mountain lakelet in which so often he had bathed and drunk. The thought of it made him hate the stout rope. But he made no serious effort to free himself. He had been tied there,--supposedly by the Master's command. And, as a well-trained dog, it was his place to stay where he was, until the Master should free him. So, apart from an instinctive tug or two at his moorings, he submitted to his fate. But, in mid-evening, something occurred, to change his viewpoint, in this matter of nonresistance. The line of fire, climbing the mountain toward him, had encountered a marshy stretch; where, in normal weather, water stood inches deep. Despite the drought, there was still enough moisture to stay the advance of the red line until the dampness could be turned to dust and tindery vegetation. And, in the meanwhile, after the custom of its kind, the fire had sought to spread to either side. Stopped at the granite-outcrop to the right, it had rolled faster through the herbage to the left. Thus, by the time the morass was dry enough for the flame to pass it, there was a great sickle of crawling red fire to the left; which encircled a whole flank of the mountain and which was moving straight upward. Lad knew nothing of this; nor why the advance of the fire's direct line had been so long checked. Nor did he know, presumably, that this sickle of flame was girdling the mountain-flank; like a murderous net; hemming in all live things within the flaming arc and forcing them on in panic, ahead of its advance. Perhaps he did not even note the mad scurryings in undergrowth and bramble, in front of the oncoming blaze. But one thing, very speedily, became apparent to him:--