He plunged in among the big spruce trees. The trail was faint. A foot of snow had fallen since the last sled had passed over, and he was glad he was without a sled, travelling light. In fact, he carried nothing but the lunch wrapped in the handkerchief. He was surprised, however, at the cold. It certainly was cold, he concluded, as he rubbed his numbed nose and cheek-bones with his mittened hand. He was a warm-whiskered man, but the hair on his face did not protect the high cheek-bones and the eager nose that thrust itself aggressively into the frosty air.

     At the man's heels trotted a dog, a big native husky, the proper wolf-dog, grey-coated and without any visible or temperamental difference from its brother, the wild wolf. The animal was depressed by the tremendous cold. It knew that it was no time for travelling. Its instinct told it a truer tale than was told to the man by the man's judgment. In reality, it was not merely colder than fifty below zero; it was colder than sixty below, than seventy below. It was seventy-five below zero. Since the freezing-point is thirty-two above zero, it meant that one hundred and seven degrees of frost obtained. The dog did not know anything about thermometers. Possibly in its brain there was no sharp consciousness of a condition of very cold such as was in the man's brain. But the brute had its instinct. It experienced a vague but menacing apprehension that subdued it and made it slink along at the man's heels, and that made it question eagerly every unwonted movement of the man as if expecting him to go into camp or to seek shelter somewhere and build a fire. The dog had learned fire, and it wanted fire, or else to burrow under the snow and cuddle its warmth away from the air.