Next day, Tuesday, June 30, at 6 a.m., the descent began again.  
We were still following the gallery of lava, a real natural staircase, and as gently sloping as those inclined planes which in some old houses are still found instead of flights of steps. And so we went on until 12.17, the, precise moment when we overtook Hans, who had stopped.
 
"Ah! here we are," exclaimed my uncle, "at the very end of the chimney."
 
I looked around me. We were standing at the intersection of two roads, both dark and narrow. Which were we to take? This was a difficulty.
 
Still my uncle refused to admit an appearance of hesitation, either before me or the guide; he pointed out the Eastern tunnel, and we were soon all three in it.
 
Besides there would have been interminable hesitation before this choice of roads; for since there was no indication whatever to guide our choice, we were obliged to trust to chance.
 
The slope of this gallery was scarcely perceptible, and its sections very unequal. Sometimes we passed a series of arches succeeding each other like the majestic arcades of a gothic cathedral. Here the architects of the middle ages might have found studies for every form of the sacred art which sprang from the development of the pointed arch. A mile farther we had to bow our heads under corniced elliptic arches in the romanesque style; and massive pillars standing out from the wall bent under the spring of the vault that rested heavily upon them. In other places this magnificence gave way to narrow channels between low structures which looked like beaver's huts, and we had to creep along through extremely narrow passages.
 
The heat was perfectly bearable. Involuntarily I began to think of its heat when the lava thrown out by Snæfell was boiling and working through this now silent road. I imagined the torrents of fire hurled back at every angle in the gallery, and the accumulation of intensely heated vapours in the midst of this confined channel.
 
I only hope, thought I, that this so-called extinct volcano won't take a fancy in his old age to begin his sports again!
 
I abstained from communicating these fears to Professor Liedenbrock. He would never have understood them at all. He had but one idea—forward! He walked, he slid, he scrambled, he tumbled, with a persistency which one could not but admire.
 
By six in the evening, after a not very fatiguing walk, we had gone two leagues south, but scarcely a quarter of a mile down.
 
My uncle said it was time to go to sleep. We ate without talking, and went to sleep without reflection.
 
Our arrangements for the night were very simple; a railway rug each, into which we rolled ourselves, was our sole covering. We had neither cold nor intrusive visits to fear. Travellers who penetrate into the wilds of central Africa, and into the pathless forests of the New World, are obliged to watch over each other by night. But we enjoyed absolute safety and utter seclusion; no savages or wild beasts infested these silent depths.
 
Next morning, we awoke fresh and in good spirits. The road was resumed. As the day before, we followed the path of the lava. It was impossible to tell what rocks we were passing: the tunnel, instead of tending lower, approached more and more nearly to a horizontal direction, I even fancied a slight rise. But about ten this upward tendency became so evident, and therefore so fatiguing, that I was obliged to slacken my pace.
 
"Well, Axel?" demanded the Professor impatiently.
 
"Well, I cannot stand it any longer," I replied.
 
"What! after three hours' walk over such easy ground."
 
"It may be easy, but it is tiring all the same."
 
"What, when we have nothing to do but keep going down!"
 
"Going up, if you please."
 
"Going up!" said my uncle, with a shrug.
 
"No doubt, for the last half-hour the inclines have gone the other way, and at this rate we shall soon arrive upon the level soil of Iceland."
 
The Professor nodded slowly and uneasily like a man that declines to be convinced. I tried to resume the conversation. He answered not a word, and gave the signal for a start. I saw that his silence was nothing but ill-humour.
 
Still I had courageously shouldered my bur............