The doctor had a piece, a foot in diameter, cut through, and he began
to smooth it with the hatchet; then he equalized the surface still
further with his knife; then he polished it with his hand, and he
obtained soon a lens as transparent as if it had been made of the most
magnificent crystal. Then he returned to the snow-house, where he took
a piece of tinder and began his experiment. The sun was shining
brightly; the doctor held the lens so that the rays should be focused
on the tinder, which took fire in a few seconds.

[Illustration]

"Hurrah! hurrah!" cried Johnson, who could hardly trust his eyes. "O
Doctor, Doctor!"

The old sailor could not restrain his joy; he was coming and going
like a madman. The doctor had returned to the house; a few minutes
later the stove was roaring, and soon a delicious odor of cooking
aroused Bell from his torpor. It may be easily imagined how the feast
was enjoyed; still the doctor advised his friends to partake in
moderation; he set an example, and while eating he again began to
talk.

"To-day is a lucky day," he said; "we have food enough for our
journey. But we mustn't fall asleep in the delights of Capua, and we'd
better start out again."

"We can't be more than forty-eight hours from the _Porpoise_," said
Altamont, who could now begin to speak once more.

"I hope," said the doctor, smiling, "that we shall find material for a
fire there."

"Yes," said the American.

"For, if my ice lens is good," continued the doctor, "there would
still be something desired on cloudy days, and there are many of them
less than four degrees from the Pole."

"True!" said Altamont with a sigh, "less than four degrees! My ship
has gone nearer than any yet has been!"

"Forward!" said Hatteras, quickly.

"Forward!" repeated the doctor, gazing uneasily at the two captains.

The strength of the travellers soon returned; the dogs had eaten
freely of the bear's flesh, and they continued their journey
northward. During their walk the doctor tried to draw from Altamont
the object of his expedition, but the American gave only evasive
answers.

"There are two men to be watched," he whispered to the boatswain.

"Yes," answered Johnson.

"Hatteras never says a word to the American, and the American seems to
show very little gratitude. Fortunately I am here."

"Dr. Clawbonny," answered Johnson, "since this Yankee has returned to
life, I don't like his face much."

"Either I'm mistaken,"