The smoke was blinding. Nothing could be seen but smoke for a time. Then the dark gray clouds turned red, and Ned knew that he was nearing the advance line of the fire, and that it was mounting to the very tops of the giant trees on the plain—or elevated plateau, rather, for, though comparatively smooth of surface and heavily timbered, it was far above sea level.
If you look on an enlarged map of northern Montana you will see that the Rocky Mountains do not consist of one great, massive range. There are ridges and valleys, and plateaus extending for hundreds of miles along the British frontier. There are peaks from which the snow never disappears, and there are timber lines which crawl almost to the summit of other peaks. There are fertile valleys where cattle grow fat, and great gorges where beasts of prey await their victims in thickets.
It is the timber on this great stretch of country that the United States government is trying to save.
The heat was blistering now, and Ned feared for the safety of his gasoline tanks. At a motion from him Frank removed his coat, carefully, for a slight movement in the air is sometimes productive of disastrous results, placed it over the tanks, after a great effort, and managed to saturate it with water from one of the bags.
Through the smoke a line of tree tops now came into view, low down, and the boys knew that they had passed the fire line. Ned tried to slow down, but found that he must keep the motors going in order to retain control of the machine.
“There’s a clear space ahead!” Frank shouted, and Ned dropped. Then a giant trunk obtruded itself, and the boy tried to dip and whirl so as to dodge it, but the pressure of the wind was too strong.
The machine headed straight for the tree, which seemed to Frank to be about a thousand feet high.
“Hang on to the first thing that comes to your hands if she strikes!” Ned shouted. “But stick to the ’plane as long as she is clear. There may be a current of air which will sweep us away from that tree.”
“Here’s hoping!” Frank gasped back, and then the smoke shut out the view, making the situation doubly dangerous.