Leaning over the edge of our narrow standing ground, I observed that the bottom of the hole was still invisible.
The same manoeuvre was repeated with the cord, and half an hour after we had descended another two hundred feet.
I don’t suppose the maddest geologist under such circumstances would have studied the nature of the rocks that we were passing. I am sure I did trouble my head about them. Pliocene, Miocene, Eocene, Cretaceous, Jurassic, Triassic, Permian, Carboniferous, Devonian, Silurian, or Primitive was all one to me. But the Professor, no doubt, was pursuing his observations or taking notes, for in one of our halts he said to me:
“The farther I go the more confidence I feel. The order of these volcanic formations affords the strongest confirmation to the theories of Davy. We are now among the primitive rocks, upon which the chemical operations took place which are produced by the contact of elementary bases of metals with water. I repudiate the notion of central heat altogether. We shall see further proof of that very soon.”
No variation, always the same conclusion. Of course, I was not inclined to argue. My silence was taken for consent and the descent went on.
Another three hours, and I saw no bottom to the chimney yet. When I lifted my head I perceived the gradual contraction of its aperture. Its walls, by a gentle incline, were drawing closer to each other, and it was beginning to grow darker.
Still we kept descending. It seemed to me that the falling stones were meeting with an earlier resistance, and that the concussion gave a more abrupt and deadened sound.