e said, "I have a good many to verify and prove,
in order that we may know our exact position. I wish to be able on our
return to the upper regions to make a map of our journey, a kind of
vertical section of the globe, which will be, as it were, the profile of
the expedition."

"That would indeed be a curious work, Uncle; but can you make your
observations with anything like certainty and precision?"

"I can. I have never on any occasion failed to note with great care the
angles and slopes. I am certain as to having made no mistake. Take the
compass and examine how she points."

I looked at the instrument with care.

"East one quarter southeast."

"Very good," resumed the Professor, noting the observation, and going
through some rapid calculations. "I make out that we have journeyed two
hundred and fifty miles from the point of our departure."

"Then the mighty waves of the Atlantic are rolling over our heads?"

"Certainly."

"And at this very moment it is possible that fierce tempests are raging
above, and that men and ships are battling against the angry blasts just
over our heads?"

"It is quite within the range of possibility," rejoined my uncle,
smiling.

"And that whales are playing in shoals, thrashing the bottom of the sea,
the roof of our adamantine prison?"

"Be quite at rest on that point; there is no danger of their breaking
through. But to return to our calculations. We are to the southeast, two
hundred and fifty miles from the base of Sneffels, and, according to my
preceding notes, I think we have gone sixteen leagues in a downward
direction."

"Sixteen leagues--fifty miles!" I cried.

"I am sure of it."

"But that is the extreme limit allowed by science for the thickness of
the earth's crust," I replied, referring to my geological studies.

"I do not contravene that assertion," was his quiet answer.

"And at this stage of our journey, according to all known laws on the
increase of heat, there should be here a temperature of <i>fifteen hundred
degrees of Reaumur</i>."

"There should be--you say, my boy."

"In which case this granite would not exist, but be in a state of
fusion."

"But you perceive, my boy, that it is not so, and that facts, as usual,
are very stubborn things, overruling all theories."

"I am forced to yield to the evidence of my senses, but I am
nevertheless very much surprised."

"What heat does the thermometer really indicate?" continued the
philosopher.

"