The air freshened somewhat, and the forest lightened. Almost abruptly we rode out to the edge of a great, wide canyon. It must have crossed the forest at right angles to the canyon we had left. It was twice as wide and deep as any I had yet seen. In the bottom wound a broad brook. “Which way now?” asked Herky. Bill shook his head. Far to our right a pall of smoke moved over the tree-tops, to our left was foggy gloom, behind rolled the unceasing roar. We all looked straight across. Probably each of us harbored the same thought. Before that wind the fire would leap the canyon in flaming bounds, and on the opposite level was the thick pitch-pine forest of Penetier proper. So far we had been among the foot-hills. We dared not enter the real forest with that wild-fire back of us. Momentarily we stood irresolute. It was a pause full of hopelessness, such as might have come to tired deer, close harried by hounds. The winding brook and the brown slope, comparatively bare of trees, brought me a sudden inspiration. “Back-fire! Back-fire!” I cried to my companions, in wild appeal. “We must back-fire. It's our chance! Here's the place!” Bud scowled and Herky grumbled, but Bill grasped at the idea. “I've heerd of back-firin'. The rangers do it. But how? How?” They caught his hope, and their haggard faces lightened. “Kid, we ain't forest rangers,” said Herky. “Do you know what you're talkin' about?” “Yes, yes! Come on! We'll back-fire!” I led the way down the slope, and they came close at my heels. I rode into the shallow brook, and dismounted about the middle between the banks. I hung my coat on the pommel of my saddle. “Bud, you and Bill hold the horses here!” I shouted, intensely excited. “Herky, have you matches?” “Nary a match.” “Hyar's a box,” said Bill, tossing it. “Come on, Herky! You run up the brook. Light a match, and drop it every hundred feet. Be sure it catches. Lucky there's little wind down here. Go as far as you can. I'll run down!” We splashed out of the brook and leaped up the bank. The grass was long and dry. There was brush near by, and the pine-needle mats almost bordered the bank. I struck a match and dropped it. Sis-s-s! Flare! It was almost like dropping a spark into gunpowder. The flame ran quickly, reached the pine-needles, then sputtered and fizzed into a big blaze. The first pine-tree exploded and went off like a rocket. We were startled by the sound and the red, up-leaping pillar of fire. Sudden heat shot back at us as if from a furnace. Great sparks began to fall. “It's goin'!” yelled Herky-Jerky, his voice ringing strong. He clapped his hat down on my bare head. Then he started running up-stream.