CHAPTER EIGHTEEN

At eight in the evening, I saw sunlight above us. The light was bright enough so we could see around us.

"Well, Axel, what do you think of this?" my uncle asked. "What a peaceful night of sleep we have had."

"Yes, it's quiet at the bottom of this hole," I said, "but there is something frightening about such quietness."

"If you're frightened already, how worried will you be later on? We haven't even gone into the Earth yet."

"What do you mean?"

"I mean that we've only reached the surface of the island. Remember, we climbed the mountain of Sneffels first, then we climbed down again, but inside."

"Are you sure?"

"Yes, look at this instrument that I've brought. It measures how far into the Earth we've gone. We're only at the level of the sea now; we haven't gone into the Earth yet."

"But," I said, "won't the increasing pressure be painful for us the deeper we go?"

"No, we'll go down slowly, so we get used to breathing the air under pressure."

We had some breakfast and packed our things while my uncle made more calculations about how we would go into the Earth.

"Now, we're really going down into the Earth. This is the exact time when our journey begins," my uncle told me with a smile.

The three of us then picked up our lanterns to guide us in the darkness.

"Let's go!" my uncle said.

Each of us picked up our things and began walking. I looked one last time at the Icelandic sky, which I would never see again.

During the last volcanic explosion of Sneffels, in 1229, lava had come through this passageway. I saw the lava on the walls, which was thick and shiny. As we walked, we had to go slowly, or we would fall and slide down the passageway. Luckily, there were rocks coming out from the walls that we could use as steps. It was as if we were walking down a steep hill, and had to walk slowly. At some points, usually above us, I could see the lava had turned into crystals, hanging down.

"It's amazing!" I cried out. "Uncle look at how the lava turns from reddish brown to bright yellow, it's incredible! And look at those crystals shining above us."

"Ah, you're beginning to open your eyes, Axel," my uncle replied. "You'll see even better sights further on, just keep walking."

Our instrument showing our direction, called the compass, pointed southeast. As we walked, the temperature hadn't risen too much. I was quite surprised, two hours after we began walking into the Earth, the temperature was still fifty degrees, increased only seven degrees, which made me think we were walking more horizontally, near the Earth's surface, than vertically, towards the center of the Earth.

At about eight o'clock that evening, my uncle decided we should stop. Hans immediately sat down. I was surprised to feel a light wind pass by, but after walking for the past seven hours, I was too tired and hungry to wonder about the mysterious wind. We sat down and ate together. I was worried, however, that we would soon run out of water, as half our supply was gone. My uncle expected that we would find underground rivers to fill our bottles, but we had not found any.

"You're surprised that we haven't found any water yet?" he asked.

"Yes, and worried, too. We only have enough water for five days."

"Don't worry, Axel. I promise you that we'll find water—even more than we need."

"When?"

"When we finish walking through this passageway. Water could never go through these thick walls of lava."

"But we haven't gone too far vertically. It seems that we've walked more horizontally than vertically," I explained to my uncle.

"Why do you think so?"

"Because the temperature would be higher than it is now if we'd gone far into the Earth."

"What is the temperature now?" my uncle asked me with a smile.

"It's fifty-nine degrees," I answered, "which means that it's gone up only sixteen degrees since we started. The temperature inside the Earth should increase by one degree for every forty feet deeper into the Earth, but that calculation can change at different places on the Earth. I calculate that we've only gone around six hundred-forty feet into the Earth."

"Well," my uncle said, "I have calculated that we've gone nearly ten thousand feet into the Earth."

"That's impossible!"

"Not at all!" The professor was correct. The temperature now should have been a hundred and eighty-six degrees, but it was actually only fifty-nine. This eased some of my worries.

(end of section)