Walter threw his rifle to his shoulder and fired again and again at the rotating disc. The cold had became intense and he could not control the actions of his muscles and his rifle wavered about. He threw himself flat on the ground, and, with an almost superhuman effort, steadied himself for a moment and fired. His aim was true, and with a terrific crash the reflector split into a thousand fragments. Dr. Bird staggered to his feet.
"It's out of order for a moment!" he cried. "To the house while we can!"
As swiftly as his numbed feet would allow him, he stumbled toward the house. The muzzle of the rifle again projected from the loophole and with its crack the doctor staggered for a moment and then fell. Walter's rifle spoke again and the rifle disappeared through the loophole with a spasmodic jerk. Carnes stumbled over the doctor.
"Are you hit badly?" he gasped through chattering teeth.
"I'm not hit at all," muttered the doctor. "I stumbled and fell just as he fired. Look out! He's going to shoot again!"
The rifle barrel came slowly into view through the loophole. Walter fired, but his bullet went wild. Carnes threw himself behind a rock for protection.
The rifle swung in Walter's direction and paused. As it did so, from the house came a strangled cry and a sound as of a blow. The rifle barrel disappeared, and the sounds of a struggle came from the building.
"Come on!" cried Carnes as he rose to his feet, and made his stumbling way forward, the others following at the best speed which their numbed limbs would allow.
As they reached the door they were aware of a struggle which was going on inside. With an oath the doctor threw his massive frame against the door. It creaked, but the solid oak of which it was composed was proof against the attack, and he drew back for another onslaught. From the house came a pistol shot, followed by a despairing cry and a guttural shout. Reinforced by Carnes, the doctor threw his weight against the door again. With a rending crash it gave, and they fell sprawling into the cabin. The doctor was the first one on his feet.
"Who are you?" asked a voice from one corner. The doctor whirled like a flash and covered the speaker with his pistol.
"I am unarmed," the voice replied. "Who are you?"