This last observation referred to the obscure gallery, and was indicated to us by the compass.
“Now, Harry,” cried the Professor, in an enthusiastic tone of voice, “we are truly about to take our first step into the interior of the earth; never before visited by man since the first creation of the world. You may consider, therefore, that at this precise moment our travels really commence.”
As my uncle made this remark, he took in one hand the Ruhmkorf coil apparatus, which hung around his neck, and with the other he put the electric current into communication with the worm of the lantern. And a bright light at once illumined that dark and gloomy tunnel!
The effect was magical!
Hans, who carried the second apparatus, had it also put into operation. This ingenious application of electricity to practical purposes enabled us to move along by the light of an artificial day, amid even the flow of the most inflammable and combustible gases.
“Forward!” cried my uncle. Each took up his burden. Hans went first, my uncle followed, and I going third, we entered the somber gallery!
Just as we were about to engulf ourselves in this dismal passage, I lifted up my head, and through the tubelike shaft saw that Iceland sky I was never to see again!
Was it the last I should ever see of any sky?
The stream of lava flowing from the bowels of the earth in 1219 had forced itself a passage through the tunnel. It lined the whole of the inside with its thick and brilliant coating. The electric light added very greatly to the brilliancy of the effect.
The great difficulty of our journey now began. How were we to prevent ourselves from slipping down the steeply inclined plane? Happily some cracks, abrasures of the soil, and other irregularities, served the place of steps; and we descended slowly; allowing our heavy luggage to slip on before, at the end of a long cord.
But that which served as steps under our feet became in other places stalactites. The lava, very porous in certain places, took the form of little round blisters. Crystals of opaque quartz, adorned with limpid drops of natural glass suspended to the roof like lusters, seemed to take fire as we passed beneath them. One would have fancied that the genii of romance were illuminating their underground palaces to receive the sons of men.
“Magnificent, glorious!” I cried in a moment of involuntary enthusiasm, “what a spectacle, Uncle! Do you not admire these variegated shades of lava, which run through a whole series of colors, from reddish brown to pale yellow—by the most insensible degrees? And these crystals, they appear like luminous globes.”
“You are beginning to see the charms of travel, Master Harry,” cried my uncle. “Wait a bit, until we advance farther. What we have as yet discovered is nothing—onward, my boy, onward!”
It would have been a far more correct and appropriate expression, had he said, “let us slide,” for we were going down an inclined plane with perfect ease. The compass indicated that we were moving in a southeasterly direction. The flow of lava had never turned to the right or the left. It had the inflexibility of a straight line.
Nevertheless, to my surprise, we found no perceptible increase in heat. This proved the theories of Humphry Davy to be founded on truth, and more than once I found myself examining the thermometer in silent astonishment.
Two hours after my departure it only marked fifty-four degrees Fahrenheit. I had every reason to believe from this that 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 observation to himself.
About eight o’clock in the evening, my uncle gave the signal for halting. 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 draft? But this was a question which I did not care to discuss just then. Fatigue and hunger made me incapable of reasoning. An unceasing march of seven 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.