un appeared, Clawbonny ascended the
wall of rock which rose above Doctor's House; it terminated suddenly
in a sort of truncated cone; the doctor reached the summit with some
little difficulty, and from there his eye beheld a vast expanse of
territory which looked as if it were the result of some volcanic
convulsion; a huge white canopy covered land and sea, rendering them
undistinguishable the one from the other. The doctor, when he saw that
this rock overlooked all the surrounding plain, had an idea,--a fact
which will not astonish those who are acquainted with him. This idea
he turned over, pondered, and made himself master of by the time he
returned to the house, and then he communicated it to his companions.

[Illustration: "The doctor reached the summit with some little
difficulty."]

"It has occurred to me," he said to them, "to build a lighthouse at
the top of the cone up there."

"A lighthouse?" they cried.

"Yes, a lighthouse; it will be of use to show us our way back at night
when we are returning from distant excursions, and to light up the
neighborhood in the eight months of winter."

"Certainly," answered Altamont, "such an apparatus would be useful;
but how will you build it?"

"With one of the _Porpoise's_ lanterns."

"Very good; but with what will you feed the lamp? With seal-oil?"

"No; it doesn't give a bright enough light; it could hardly pierce the
fog."

"Do you think you can get hydrogen from our coal and make illuminating
gas?"

"Well, that light would not be bright enough, and it would be wrong to
use up any of our fuel."

"Then," said Altamont, "I don't see--"

"As for me," answered Johnson, "since the bullet of mercury, the ice
lens, the building of Fort Providence, I believe Dr. Clawbonny is
capable of anything."

"Well," resumed Altamont, "will you tell us what sort of a light you
are going to have?"

"It's very simple," answered the doctor; "an electric light."

"An electric light!"

"Certainly; didn't you have on board of the _Porpoise_ a Bunsen's pile
in an uninjured state?"

"Yes," answered the American.

"Evidently, when you took it, you intended to make some experiments,
for it is complete. You have the necessary acid, and the wires
isolated, hence it would be easy for us to get an electric light. It
will be more brilliant, and will cost nothing."

"That is perfect," answered the boatswain, "and the less time we
lose--"

"Well, the materials are there," answ