Unbelievable as it was that human beings so beset could continue to exist, they proceeded thus for the space of two days. At the end of each short march they huddled together in their robes--the girl and the dog and the man, and warmed with the heat of their bodies their frozen food, until they might chew and mumble it. Still closer they huddled for their fitful slumbers. On the march the girl swooned many times with the throbbing pain of her swollen ankle. Always she awoke to find herself in the man's arms. They wound about her, a living barrier, which death itself could not pass. All the weary miles of the weary marches he carried her. Under her weight, every muscle of his splendid body was racked with the pangs of torture, until the fierce pain was succeeded by a numbness that slowly enveloped his body and crept up to his brain. He felt that he had been transformed into a marching machine of unfeeling steel. He went on, bearing his burden, mile after mile, stolidly, doggedly, splendidly. Two days passed. Polaris roused himself from where they slept huddled in a little hollow in the snow. The mere rising to his feet was a matter of minutes, and he swayed uncertainly. Once more he fought fiercely with the temptation to acknowledge that this, indeed, was the end, and to follow the footsteps of Kalin. Once more his courage upheld his resolve. He would go on. He would walk until he could walk no longer. Then he would crawl on his hands and knees, drag himself forward with his hands, but he would go on. As he stooped there came to his ears a humming, faint and far away. He arranged the robe and gathered Rose Emer gently into the sling. With immense effort he straightened his knees and back and stood erect again. Again the humming noise, nearer now, and louder! Marcus floundered out of the hollow, both ears pricked, and growled a weak, hoarse defiance. Polaris followed. From a distant humming the noise rose to a shrilling; from a shrilling to a prolonged shriek. The man came out of the hollow, and his eyes sought the sky, whence came the sound. His heart bounded and threatened to burst in his breast. * * * * * Sharply outlined against the dazzling sky, sailing along on steady planes like a great white bird of the air, her engine purring and thrilling, and her propeller screaming, an air-ship passed athwart his vision! Enthralled, his eyes followed it. It was less than half a mile away to his right. He tried to shout aloud, but his voice was feeble, and seemed to be thrown back at him from the air. Before he could rouse the girl, or convey to her senses what was occurring, the ship of the air had vanished. It dipped out of sight into the mouth of a little valley.