uneasily in his chair,
and said: "What's up, Doctor? I never knew you to drink. Getting off?"
tapping his _os frontis_ with his forefinger significantly.

"Denison," replied the Doctor, unheeding the innuendoes of his friend,
"I tell you that I have a plan for going to, and returning from, the
North Pole with perfect safety, absolute certainty, and a degree of
comfort that will reduce the whole expedition to the level of a glorious
picnic." Denison indulged in a long, low whistle.

"Draw it a little milder, Doctor. Go to and return from the North Pole
with perfect safety, certainty, comfort, and pleasure! What do you mean?
I never heard of anything so preposterous in my life!"

"Hitch up to the desk here, and I will soon tell you what I mean," cried
the Doctor. Denison complied, and the Doctor, seizing a pencil, drew
upon a leaf of the scratch book, with a few vigorous strokes, a sketch
of a globe, thus:

[Illustration]

"There," said he, as he gave a few finishing touches. "There you have
the idea."

"Well, go on."

"This sketch represents a mammoth globe of aluminum, two hundred feet in
diameter, as you will notice.

"I see," assented Denison.

"We have, then, a great hollow globe, consisting, as I said before, of
aluminum. I have chosen that material for two obvious reasons; lightness
and strength. The globe is simply to be floated by heating the
atmosphere within it."

"What will you heat it with, and how long do you suppose it will be
before your globe returns to the earth?" asked Denison.

"Your questions are quite practical, and I am ready to answer them.
There are to be three skins or coverings to our globe, with a foot of
space (or air blanket, if you please) between them. This affords us two
air chambers that materially prevent the radiation of heat. Once heated,
a very little fuel will keep the interior of our great air-ship at the
desired temperature. You see, at the inferior or lower part of the ship,
a square apartment attached, plentifully supplied with windows. That
represents the living and store rooms. The living rooms are to be
comfortably furnished, and no reason can be alleged why we should not
enjoy in them absolute comfort. In our store-rooms, we will carry one
year's supply of food. And in tanks of sufficient size, petroleum (or
whatever combustible we conclude to be most suitable) for heating and
cooking purposes. See?"

"I see," said Denison.

"You will observe that so conser