Soon he heard Johnson's voice in the distance calling out "Ready."

"All right," was the reply.

Johnson pulled his rope vigorously, and then rushed to the loop-hole to see the effect. The thin shell of ice had given way, and the body of the fox lay among the ruins. The bears were somewhat scared at first, but the next minute had eagerly rushed to seize the booty.

"Fire!" called out Johnson, and at once the electric spark was sent along the lines right into the keg of powder. A formidable explosion ensued; the house was shaken as if by an earthquake, and the walls cracked asunder. Hatteras, Altamont, and Bell hurried out with the guns, but they might spare their shot, for four of the bears lay dead, and the fifth, half roasted, though alive, was scampering away in terror as fast as his legs could carry him.

"Hurrah! Three cheers for Clawbonny," they shouted and overwhelmed the Doctor with plaudits and thanks.

CHAPTER XIV.

AN ARCTIC SPRING.

The prisoners were free, and their joy found vent in the noisiest demonstrations. They employed the rest of the day in repairing the house, which had suffered greatly by the explosion. They cleared away the blocks piled up by the animals, and filled up the rents in the walls, working with might and main, enlivened by the many songs of old Johnson.

Next morning there was a singular rise in the temperature, the thermometer going up to 15° above zero.