“I see a peninsula looking like a thigh bone with the knee bone at the end of it.”

“A very fair comparison, my lad. Now do you see anything upon that knee bone?”

“Yes; a mountain rising out of the sea.”

“Right. That is Snæfells.”

“That Snæfells?”

“It is. It is a mountain five thousand feet high, one of the most remarkable in the world, if its crater leads down to the centre of the earth.”

“But that is impossible,” I said shrugging my shoulders, and disgusted at such a ridiculous supposition.

“Impossible?” said the Professor severely; “and why, pray?”

“Because this crater is evidently filled with lava and burning rocks, and therefore⁠—”