When I finally came back to my senses, my face was wet with tears.
I had no idea how long I had been unconscious. I had completely lost track of time. I was utterly alone, buried deep inside the earth, with no idea whether I would ever see my companions again.
The fall had left me badly injured, and I had lost a great deal of blood. Yet somehow, I was still alive.
My first thought was almost one of surprise.
Why wasn’t I dead?
Since I was still alive, there must still be something I could do. But I was too exhausted to think clearly. I pushed every thought out of my mind and curled up against the cold granite wall, overwhelmed by pain and despair.
I was beginning to lose consciousness again. I felt as though this was the final struggle before everything simply disappeared.
Then, suddenly, a terrible rumbling sound reached my ears.
It sounded like distant thunder rolling through the earth. Mixed with it were deep voices that seemed to fade one after another into the darkness.
I wondered where the noise had come from.
Perhaps there had been some violent movement deep inside the earth. Maybe underground gases had exploded, or a huge mass of rock had collapsed somewhere nearby.
I listened carefully, hoping the strange sound would come again.
Fifteen minutes passed.
Nothing.
The tunnel was completely silent. It was so quiet that I could hear my own heart beating.
I waited.
Then my ear happened to touch the wall.
Very faintly, I thought I heard something.
Voices.
They were distant and unclear, almost like whispers carried through the darkness.
My whole body trembled with excitement.
“It must be a hallucination,” I whispered. “It can’t be real.”
But I listened harder.
No. It really was the sound of human voices.
I still couldn’t understand what they were saying. I was far too weak to hear clearly, but one thing was certain.
Someone was speaking.
Then a terrible thought came to me.
What if it was only my own voice coming back as an echo?
Perhaps I had been shouting without even realizing it.
I pressed my lips tightly together and put my ear against the granite wall again.
No.
These were definitely human voices.
With enormous effort, I dragged myself along the wall until I reached a place where the sound became clearer.
The voices were still strange and distant. I could hear words, but they were almost impossible to understand.
Then one word came through clearly.
“Forlorad.”
It was repeated several times in a voice filled with sorrow.
What did that word mean?
And who was saying it?
It had to be my uncle or Hans.
If I could hear them, perhaps they could hear me.
“Help!” I shouted as loudly as I could. “Help! I’m dying!”
Then I stopped and listened.
I barely dared to breathe.
I waited for a cry, a question, even a sigh.
Nothing.
The silence returned.
Maybe my voice was simply too weak to reach them.
“It must be them,” I told myself. “Who else could possibly be buried this far beneath the earth?”
The idea that anyone else could be here was impossible.
I listened again.
As I moved my ear slowly along the wall, I discovered that there was one particular spot where the voices became much louder.
Again I heard the word.
“Forlorad.”
Then the deep rumbling sound returned, like thunder moving through the earth.
I began to understand.
“The sound isn’t coming through the solid rock,” I thought. “The walls around me are granite. Even a huge explosion couldn’t send a sound directly through them like this.”
“It must be traveling through the gallery itself.”
“Perhaps this place has some unusual acoustic properties.”
I listened again.
And then I heard something that made my heart race.
My name.
“Harry.”
Someone had clearly spoken my name.
It was my uncle.
He was talking to Hans, and now I understood that “forlorad” was a Danish word.
Everything suddenly made sense.
The sound was traveling through the gallery, almost as if the walls were carrying it like an electric wire carries a current.
If I wanted my uncle to hear me, I had to speak along the wall in the same way.
But I had no time to waste.
If my uncle and Hans moved even a few feet away, this strange acoustic effect might disappear, and I would lose my only connection with them.
I crawled back toward the wall.
Then I pressed my lips close to it.
“Uncle Hardwigg.”
I waited.
Sound did not travel instantly, especially this deep underground. Several seconds passed, but to me they felt like years.
Then I heard the words I had been desperate to hear.
“Harry, my boy, is that you?”
“Yes. Yes.”
“Where are you?”
“Lost.”
“And your lamp?”
“Out.”
“But the stream that was guiding you?”
“Lost!”
“Keep your courage, Harry. We’ll do everything we can.”
“Wait, Uncle,” I cried. “I don’t have enough strength to answer all your questions. But please, keep talking to me!”
The thought of complete silence terrified me.
“Keep your courage,” my uncle said. “You’re too weak to talk, so just listen.”
“We’ve been searching everywhere for you. We’ve gone both upward and downward through the galleries.”
“My dear boy, I had almost given up hope. You cannot imagine how much I have suffered, or how many tears I have shed.”
“At last, we thought you might still be somewhere along the Hansbach, so we went down again and fired our guns to send you signals.”
“Now we’ve found you, and our voices can reach each other. But it may still be a long time before we actually meet.”
“We’re communicating through some extraordinary acoustic feature of this labyrinth.”
“But don’t lose hope. Even being able to hear each other is a victory.”
While he spoke, my mind began working again.
A small, uncertain hope started growing inside me.
There was one thing I absolutely had to know.
I pressed my head against the wall again and spoke.
“Uncle.”
“My boy?”
“It is extremely important that we find out how far apart we are.”
“That shouldn’t be difficult.”
“You have your chronometer with you?”
“Of course.”
“Then hold it in your hand. Say my name and note the exact second when you speak.”
“I’ll answer as soon as I hear you, and you can note the exact second when my reply reaches you.”
“Very good.”
“The time between my question and your answer will tell us how long my voice takes to reach you.”
“Exactly, Uncle.”
“Are you ready?”
“Yes.”
“Then get ready. I’m about to say your name.”
I pressed my ear tightly against the wall.
The instant I heard him say “Harry,” I turned around, pressed my lips against the rock, and repeated the sound.
“Forty seconds,” my uncle said.
“Forty seconds passed between the two words. So the sound takes twenty seconds to travel from you to me.”
“At about 1,020 feet per second, that means you are roughly 20,400 feet away.”
“That’s about a league and a half.”
The words struck me like a death sentence.
“A league and a half,” I whispered miserably.
“We’ll cover the distance, my boy,” my uncle said cheerfully. “Trust us.”
“But do you know whether I should go up or down?” I asked weakly.
“You must go down.”
“Why?”
“You’ve reached a huge open space, almost like a crossroads. Galleries branch away from it in every direction.”
“The gallery you’re in must eventually lead to us, because all these enormous cracks and passages inside the earth seem to spread out from the great cavern where we are now.”
“So get up and keep moving.”
“Walk if you can. If you can’t walk, crawl.”
“Even sliding along the ground is better than staying where you are.”
“The slope should become quite steep, and when you reach the end, we’ll be there to catch you.”
“Come on, my boy. Start moving.”
His words gave me just enough strength to continue.
“Goodbye for now, Uncle. I’m going to leave.”
“As soon as I move away, our voices will probably stop reaching each other.”
“Goodbye, then, until we meet again.”
“Goodbye, Harry—and until we can say, ‘Welcome.'”
Those were the last words I heard before I began my long and almost hopeless journey.
It was an incredible conversation.
My uncle and I had been separated by nearly five miles of solid earth, yet somehow we had been able to speak to each other through the labyrinth below us.
We ended our conversation with words of hope.
I prayed once more and thanked God from the bottom of my heart.
I believed He had guided me to the one place where my uncle’s voice could reach me.
The strange phenomenon was actually quite natural.
Certain kinds of rock can carry sound remarkably well. Similar effects have been observed in places such as the underground galleries of St. Paul’s and the caves of Sicily.
The most famous example is the extraordinary chamber known as the Ear of Dionysius.
I remembered reading about such things when I was younger.
If my uncle and I could communicate across such an enormous distance, then there could not be any impossible obstacle between us.
All I had to do was follow the direction from which his voice had come.
If my strength held out, I would eventually reach him.
I forced myself to stand.
But I soon discovered that I couldn’t walk.
I had to crawl.
As I expected, the slope was extremely steep.
I let myself slide downward.
At first, I moved slowly.
Then the descent became faster.
Much faster.
Soon it became terrifying.
I tried to grab the walls.
I clutched at every rock sticking out from the sides.
I even threw myself backward to slow myself down.
Nothing worked.
I was far too weak.
Suddenly, the ground disappeared beneath me.
I was thrown into a dark, empty space.
Then I crashed against the jagged walls of a vertical passage that was like a gigantic well.
My head struck a sharp rock.
Everything went black.
I lost all awareness of the world around me.
As far as I knew, death had finally claimed me.