He could soon see a broadening patch of burned-over prairie in the midst of the swirling flames and smoke. His pony snorted, and backed away from the approach-fire; but Pratt wheeled the grey around to the westward, and where the flames merely crept and sputtered through the greasewood and against the wind, he spurred his mount to leap over the line of fire. The earth was hot, and every time the pony set a hoof down smoke or sparks flew upward; but Pratt had to get back to the trail. With the quirt he forced on the snorting grey, and finally reached a place where the fire had completely passed and the ground was cooler. Ashes flew in clouds about him; the smoke from the west drove in a thick mass between him and the darkened sky. Only the glare of the roaring fire revealed objects and landmarks. The backfire had burned for many yards westward, to meet the threatening wave of flame flying on the wings of the wind. To the east, the line of flame Pratt and Frances had set was rising higher and higher. He saw the wagon standing in the midst of the smoke, Mack Hinkman holding the snorting, kicking mules with difficulty, while a wild little figure on a pony galloped back from the other side of the trail. "All right, Pratt?" shrieked Frances. "Get up, Mack; we've no time to lose!" The teamster let the mules go. Yet he dared not let them take their own gait. The thought of that cracked axle disturbed him. The wagon led, however, through the smoke and dust; the two ponies fell in behind upon the trail. Frances and Pratt looked at each other. The young man was serious enough; but the girl was smiling. Something she had said a little while before kept returning to Pratt's mind. He was thinking of what would have happened had Sue Latrop, the girl from Boston, been here instead of Frances. "Goodness!" Pratt told himself. "They are out of two different worlds; that's sure! And I'm an awful tenderfoot, just as Mrs. Bill Edwards says." "What do you think of it?" asked Frances, raising her voice to make it heard above the roar of the fire and the rumble of the wagon ahead of them. "I'm scared--right down scared!" admitted Pratt Sanderson. "Well, so was I," she admitted. "But the worst is over now. We'll reach the river and ford it, and so put the fire all behind us. The flames won't leap the river, that's sure." The heat from the prairie fire was most oppressive. Over their heads the hot smoke swirled, shutting out all sight of the stars. Now and then a clump of brush beside the trail broke into flame again, fanned by the wind, and the ponies snorted and leaped aside. Suddenly Mack was heard yelling at the mules and trying to pull them down to something milder than a wild gallop. Frances and Pratt spurred their ponies out upon the burned ground in order to see ahead. Something loomed up on the trail--something that smoked and flamed like a big bonfire. "What can it be?" gasped Pratt, riding knee to knee with the range girl.