Quicker than a lynx, the dog had leaped the length of his chain across the sledge.

McCready sprang back just in time, and as Kazan reached the end of his chain he was jerked back so that his body struck sidewise against the girl.

Thorpe had turned in time to see the end of the leap.

He believed that Kazan had sprung at Isobel, and in his horror no word or cry escaped his lips as he dragged her from where she had half fallen over the sledge.

He saw that she was not hurt, and he reached for his revolver.