From up and down the valley, from the breaks between the peaks, and from the little gullies cleft in shale and rock that crept up to the snow-lines came a soft and droning murmur. It was the music of running water. That music was always in the air, for the rivers, the creeks, and the tiny streams gushing down from the snow that lay eternally up near the clouds were never still. There were sweet perfumes as well as music in the air. June and July--the last of spring and the first of summer in the northern mountains--were commingling. The earth was bursting with green; the early flowers were turning the sunny slopes into coloured splashes of red and white and purple, and everything that had life was singing--the fat whistlers on their rocks, the pompous little gophers on their mounds, the big bumblebees that buzzed from flower to flower, the hawks in the valley, and the eagles over the peaks. Even Thor was singing in his way, for as he had paddled through the soft mud a few minutes before he had rumbled curiously deep down in his great chest. It was not a growl or a roar or a snarl; it was the noise he made when he was contented. It was his song. And now, for some mysterious reason, there had suddenly come a change in this wonderful day for him. Motionless he still sniffed the wind. It puzzled him. It disquieted him without alarming him. To the new and strange smell that was in the air he was as keenly sensitive as a child's tongue to the first sharp touch of a drop of brandy. And then, at last, a low and sullen growl came like a distant roll of thunder from out of his chest. He was overlord of these domains, and slowly his brain told him that there should be no smell which he could not comprehend, and of which he was not the master. Thor reared up slowly, until the whole nine feet of him rested on his haunches, and he sat like a trained dog, with his great forefeet, heavy with mud, drooping in front of his chest. For ten years he had lived in these mountains and never had he smelled that smell. He defied it. He waited for it, while it came stronger and nearer. He did not hide himself. Clean-cut and unafraid, he stood up. He was a monster in size, and his new June coat shone a golden brown in the sun. His forearms were almost as large as a man's body; the three largest of his five knifelike claws were five and a half inches long; in the mud his feet had left tracks that were fifteen inches from tip to tip. He was fat, and sleek, and powerful. His eyes, no larger than hickory nuts, were eight inches apart. His two upper fangs, sharp as stiletto points, were as long as a man's thumb, and between his great jaws he could crush the neck of a caribou.