There was not a tree in sight—nor a single blade of grass. There was nothing but the funereal black of basaltic rock, of which the hill seemed to be one solid mass. Such was its desolation that even the horse seemed to be drooping at the sight of it. It was always the same with Buck. There was an influence about the place which always left him feeling rather hopeless. He knew the old Indian stories of superstition. He knew the awe in which the more ignorant among the white folk held this hill. But these things left him unaffected. He only regarded it from his own personal observations, which were not very enlivening.

Apart from the fact that not one atom of vegetation would grow either upon the surface or slopes of Devil’s Hill, no snows in winter had ever been known to settle upon its uninviting bosom. Long before the snow touched its surface, however low the temperature of the atmosphere, however severe a blizzard might be raging—and the Montana blizzards are notorious for their severity—the snow was turned to water, and a deluge of rain hissed upon its surface.

Then, too, there was that mystery rock in the distance of the great plateau. It was one of Nature’s little enigmas with which she loves to puzzle the mind of man. How came it there, shot up in the midst of that wide, flat stretch of rock? It stood within a few hundred yards of the eastern brink of the hill which, in its turn, was another mystery. The eastern extremity was not a mere precipice, it was a vast overhang which left Yellow Creek, upon whose banks the mining camps were pitched, flowing beneath the roof of a giant tunnel supported by a single side.

The rock on the plateau reared its misshapen head to the heavens at a height of something over two hundred feet, and its great base formed a vast cavern out of which, fanwise, spread a lake of steaming water, which flowed on to the very brink of the hill where it overshadowed the creek below. Thus it was, more than half the lake was held suspended in mid-air, with no other support than the parent hill from which its bed projected. It was an awesome freak of nature, calculated to astonish even eyes that were accustomed to the sight of it.

But Buck was not thinking of these things now. He was looking at the view. He was looking at the sky. He was looking from this great height for an explanation of the curious, ruddy light in the sunless sky, the teeming haze which weighted down the brain, and, with the slightest movement, opened the pores of the skin and set the perspiration streaming.

In all his years of the Montana hills he had never experienced such a curious atmospheric condition. Less than an hour ago he had left the Padre at the fur fort under a blazing summer sky, with the crisp mountain air whipping in his nostrils. Then, quite of a sudden, had come this change. There were no storm-clouds, and yet storm was in every breath of the superheated air he took. There was no wind, nor anything definite to alarm except this sudden blind heat and the purple hue which seemed to have spread itself over the whole world. Thus it was, as he neared the mysterious mountain, he had made up his mind to its ascent in the hope of finding, there upon the unwholesome plateau, the key to the atmospheric mystery.

But none seemed to be forthcoming, so, turning at last to the patient Cæsar, he once more returned to the saddle and rode on to the barren shores of Devil’s Lake.

The lake was a desolate spot. The waters stretched out before him, still, and silent, and black. There was not even a ripple upon its steaming surface. Here the haze hung as it always hung, and the cavern was belching forth deep mists, like the breathing of some prehistoric monster. He glanced up at the birdless rock above, and into the broken outlines of it he read the distorted features of some baleful, living creature, or some savage idol. But there was no answer here to the questions of his mind, any more than there had been on the rest of the plateau, so he rode on along the edge of the water.

He reached the extreme end of the lake and paused again. He could go no farther, for nothing but a rocky parapet, less than twenty feet wide, barred the waters from tumbling headlong to the depths below.

After a moment Cæsar grew restless, his equine nerves seemed to be on a jangle, and the steadying hand of his master had no effect. His eyes were wistful and dilated, and he glanced distrustfully from side to side, snorting loudly his evident alarm.