hollow echoing murmur peculiar to vast inclosed spaces. A light foam flew over the waves before the breath of a moderate breeze, and some of the spray fell upon my face. On this slightly inclining shore, about a hundred fathoms from the limit of the waves, came down the foot of a huge wall of vast cliffs, which rose majestically to an enormous height. Some of these, dividing the beach with their sharp spurs, formed capes and promontories, worn away by the ceaseless action of the surf. Farther on the eye discerned their massive outline sharply defined against the hazy distant horizon.
It was quite an ocean, with the irregular shores of earth, but desert and frightfully wild in appearance.
If my eyes were able to range afar over this great sea, it was because a peculiar light brought to view every detail of it. It was not the light of the sun, with his dazzling shafts of brightness and the splendour of his rays; nor was it the pale and uncertain shimmer of the moonbeams, the dim reflection of a nobler body of light. No; the illuminating power of this light, its trembling diffusiveness, its bright, clear whiteness, and its low temperature, showed that it must be of electric origin. It was like an aurora borealis, a continuous cosmical phenomenon, filling a cavern of sufficient extent to contain an ocean.
The vault that spanned the space above, the sky, if it could be called so, seemed composed of vast plains of cloud, shifting and variable vapours, which by their condensation must at certain times fall in torrents of rain. I should have thought that under so powerful a pressure of the atmosphere there could be no evaporation; and yet, under a law unknown to me, there were broad tracts of vapour suspended in the air. But then ‘the weather was fine.’ The play of the electric light produced singular effects upon the upper strata of cloud. Deep shadows reposed upon their lower wreaths; and often, between two separated fields of cloud, there glided down a ray of unspeakable lustre. But it was not solar light, and there was no heat. The general effect was sad, supremely melancholy. Instead of the shining firmament, spangled with its innumerable stars, shining singly or in clusters, I felt that all these subdued and shaded fights were ribbed in by vast walls of granite, which seemed to overpower me with their weight, and that all this space, great as it was, would not be enough for the march of the humblest of satellites.
Then I remembered the theory of an English captain, who likened the earth to a vast hollow sphere, in the interior of which the air became luminous because of the vast pressure that weighed upon it; while two stars, Pluto and Proserpine, rolled within upon the circuit of their mysterious orbits.
We were in reality shut up inside an immeasurable excavation. Its width could not be estimated, since the shore ran widening as far as eye could reach, nor could its length, for the dim horizon bounded the new. As for its height, it must have been several leagues. Where this vault rested upon its granite base no eye could tell; but there was a cloud hanging far above, the height of which we estimated at 12,000 feet, a greater height than that of any terrestrial vapour, and no doubt due to the great density of the air.
The word cavern does not convey any idea of this immense space; words of human tongue are inadequate to describe the discoveries of him who ventures into the deep abysses of earth.
Besides I could not tell upon what geological theory to account for the existence of such an excavation. Had the cooling of the globe produced it? I knew of celebrated caverns from the descriptions of travellers, but had never heard of any of such dimensions as this.
If the grotto of Guachara, in Colombia, visited by Humboldt, had not given up the whole of the secret of its depth to the philosopher, who investigated it to the depth of 2,500 feet, it probably did not extend much farther. The immense mammoth cave in Kentucky is of gigantic proportions, since its vaulted roof rises five hundred feet11 above the level of an unfathomable lake and travellers have explored its ramifications to the extent of forty miles. But what were these cavities compared to that in which I stood with wonder and admiration, with its sky of luminous vapours, its bursts of electric light, and a vast sea filling its bed? My imagination fell powerless before such immensity.
I gazed upon these wonders in silence. Words failed me to express my feelings. I felt as if I was in some distant planet Uranus or Neptune - and in the presence of phenomena of which my terrestrial experience gave me no cognisance. For such novel sensations, new words were wanted; and my imagination failed to supply them. I gazed, I thought, I admired, with a stupefaction mingled with a certain amount of fear.
The unforeseen nature of this spectacle brought back the colour to my cheeks. I was under a new course of treatment with the aid of astonishment, and my convalescence was promoted by this novel system of therapeutics; besides, the dense and breezy air invigorated me, supplying more oxygen to my lungs.
It will be easily conceived that after an imprisonment of forty seven days in a narrow gallery it was the height of physical enjoyment to breathe a moist air impregnated with saline particles.
I was delighted to leave my dark grotto. My uncle, already familiar with these wonders, had ceased to feel surprise.
“You feel strong enough to walk a little way now?” he asked.
“Yes, certainly; and nothing could be more delightful.”
“Well, take my arm, Axel, and let us follow the windings of the shore.”
I eagerly accepted, and we began to coast along this new sea. On the left huge pyramids of rock, piled one upon another, produced a prodigious titanic effect. Down their sides flowed numberless waterfalls, which went on their way in brawling but pellucid streams. A few light vapours, leaping from rock to rock, denoted the place of hot springs; and streams flowed softly down to the common basin, gliding down the gentle slopes with a softer murmur.
Amongst these streams I recognised our faithful travelling companion, the Hansbach, coming to lose its little volume quietly in the mighty sea, just as if it had done nothing else since the beginning of the world.
“We shall see it no more,” I said, with a sigh.
“What matters,” replied the philosopher, “whether this or another serves to guide us?”
I thought him rather ungrateful.
But at that moment my attention was drawn to an unexpected sight. At a distance of five hundred paces, at the turn of a high promontory, appeared a high, tufted, dense forest. It was composed of trees of moderate height, formed like umbrellas, with exact geometrical outlines. The currents of wind seemed to have had no effect upon their shape, and in the midst of the windy blasts they stood unmoved and firm, just like a clump of petrified cedars.
I hastened forward. I could not give any name to these singular creations. Were they some of the two hundred thousand species of vegetables known hitherto, and did they claim a place of their own in the lacustrine flora? No; when we arrived under their shade my surprise turned into admiration. There stood before me productions of earth, but of gigantic stature, which my uncle immediately named.
“It is only a forest of mushrooms,” said he.
And he was right. Imagine the large development attained by these plants, which prefer a warm, moist climate. I knew that the Lycopodon giganteum attains, according to Bulliard, a circumference of eight or nine feet; but here were pale mushrooms, thirty to forty feet high, and crowned with a cap of equal diameter. There they stood in thousands. No light could penetrate between their huge cones, and complete darkness reigned beneath those giants; they formed settlements of domes placed in close array like the round, thatched roofs of a central African city.
Yet I wanted to penetrate farther underneath, though a chill fell upon me as soon as I came under those cellular vaults. For half an hour we wandered
