This is my decision," replied Professor Liedenbrock, putting on one of his grandest airs. "Neither you nor anybody else knows with any certainty what is going on in the interior of this globe, since not the twelve thousandth part of its radius is known; science is eminently perfectible; and every new theory is soon routed by a newer. Was it not always believed until Fourier that the temperature of the interplanetary spaces decreased perpetually? and is it not known at the present time that the greatest cold of the ethereal regions is never lower than 40 degrees below zero Fahr.? Why should it not be the same with the internal heat? Why should it not, at a certain depth, attain an impassable limit, instead of rising to such a point as to fuse the most infusible metals?"

As my uncle was now taking his stand upon hypotheses, of course, there was nothing to be said.

"Well, I will tell you that true savants, amongst them Poisson, have demonstrated that if a heat of 360,000 degrees [1] existed in the interior of the globe, the fiery gases arising from the fused matter would acquire an elastic force which the crust of the earth would be unable to resist, and that it would explode like the plates of a bursting boiler."

"That is Poisson's opinion, my uncle, nothing more."

"Granted. But it is likewise the creed adopted by other distinguished geologists, that the interior of the globe is neither gas nor water, nor any of the heaviest minerals known, for in none of these cases would the earth weigh what it does."

"Oh, with figures you may prove anything!"

"But is it the same with facts! Is it not known that the number of volcanoes has diminished since the first days of creation? and if there is central heat may we not thence conclude that it is in process of diminution?"

"My good uncle, if you wil