For all this, however, the light in the valley was no less. Its character had changed. That was all. The rosy twilight was growing to an angry gleaming.
Steve knew his journey's end was near. How near he could not tell. He reminded himself that there must be a barrier, a dividing line, beyond which no life could endure. But he also knew that the field of Adresol must lie on the hither side of it. If that were not so, what of the Indians to whom it yielded supplies for the pleasant calm of their winter's sleep?
Steve knew he was by no means witnessing a simple volcanic eruption. It was something far greater. The suggestion of it all was so colossal that he could find no concrete form in which to express his belief. In his mind there had formed an idea that here was a whole wide territory forming one great vent to the subterranean fires demanding outlet. It seemed to him that those fires had been lit just where they now burned. Maybe they had been lit on the day that dry land was first born upon the earth, and throughout the ages had never been permitted to die out.
Fascination held him enthralled as he laboured over the weary miles of the valley. Every swamp became a potential objective for examination. Every broken hill might conceal some secret valley where subterranean heat produced a growth foreign to the more open regions. He could afford to miss no canyon however small, lest the secret he sought lay hidden there. And all the time with the hot breath of the westerly breeze in his nostrils, the lure of the sickly perfume beckoned him on.
It was sheer mental and bodily weariness that brought Steve to a prolonged halt. The heat was overpowering him at last. This strange land with its ruddy twilight had become a labour beyond endurance. It was as if the waters of the river were being evaporated into a steam which left the air unbreathable.
Halfway to the summit of a great wood-clad hill, that jettied across from the southern slopes of the valley to the northern limits beyond, he had flung himself to rest in a wide clearing surrounded by the cold delicacy of white-hued foliage. In his moment of helplessness there seemed to be no end to his journey. He felt that the great summit he was reaching towards meant only a descent beyond, and then again another, and still another steep ascent.
Only for a few moments had he sprawled, seeking rest. He was thinking and gazing back over his long solitary trail, peering into the reverse of that upon which he had looked so long. It was intensely restful thus to turn his gaze from the belching fires. Once his heavy eyelids closed. But he bestirred himself. Later he would sleep, but not now. His day's work was—Again his eyes closed heavily, and his hand fell from the support of his head.
It was that which wakened him. And in a moment a thrill of panic flashed through his nerves. With all his will flung into the effort, he forced himself to complete wakefulness. He sat up. He groped in his loosened pack. He pulled out of it the mask he had tested once before, and, with desperate haste, adjusted it over mouth and nostrils.
It had been near, so near. He knew now how nearly disaster had clutched at him. Furthermore he knew that even now the danger was by no means passed. The heavy fumes of Adresol were creeping through the woods about him. They were stealing their ghostly, paralyzing way low down upon the ground, drifting heavily along until the open below brought them to the stronger air currents which would disperse them on their eastward journey, robbing them of their deadly toxin, and reducing them to a simple sickly perfume.