our descent was far more horizontal than vertical. As for discovering the exact depth to which we had attained, nothing could be easier. The Professor, as he advanced measured the angles of deviation and inclination; but he kept the result of his observations to himself.
About eight o'clock in the evening, my uncle gave the signal for the night's rest. Hans seated himself on the ground. The lamps were hung to fissures in the lava rock. We were now in a large cavern where air was not wanting. On the contrary, it abounded. What could be the cause of this—to what atmospheric agitation could be ascribed this draught? But this was a question which I did not care to discuss just then. Fatigue and hunger made me incapable of reasoning. An almost unceasing march of twelve hours had not been kept up without great exhaustion. I was really and truly worn out; and delighted enough I was to hear the word Halt.
Hans laid out some provisions on a lump of lava, and we each supped with keen relish. One thing, however, caused us great uneasiness—our water reserve was already half exhausted. My uncle had full confidence in finding subterranean resources, but hitherto we had completely failed in so doing. I could not help calling my uncle's attention to the circumstance. "And you are surprised at this total absence of springs?" he said.
"Doubtless—I am very uneasy on the point. We have certainly not enough water to last us five days."
"Be quite easy on that matter," continued my uncle. "I answer for it we shall find plenty of water—in fact, far more than we shall want."
"But when?"
"When we once get through this crust of lava. How can you expect springs to force their way through these solid stone walls?"
"But what is there to prove that this concrete mass of lava does not extend to the center of the earth? I don't think we have as yet done much in a vertical way."
"What puts that into your head, my boy?" asked my uncle, mildly.
"Well, it appears to me that if we had descended very far below the level of the sea—we should find it rather hotter than we have."
