At first I saw absolutely nothing. My eyes, wholly unused to the effulgence of light, could not bear the sudden brightness; and I was compelled to close them. When I was able to reopen them, I stood still, far more stupefied than astonished. Not all the wildest effects of imagination could have conjured up such a scene! "The sea—the sea," I cried.

"Yes," replied my uncle, in a tone of pardonable pride; "the Central Sea. No future navigator will deny the fact of my having discovered it; and hence of acquiring a right of giving it a name."

It was quite true. A vast, limitless expanse of water, the end of a lake if not of an ocean, spread before us, until it was lost in the distance. The shore, which was very much indented, consisted of a beautiful soft golden sand, mixed with small shells, the long-deserted home of some of the creatures of a past age. The waves broke incessantly—and with a peculiarly sonorous murmur, to be found in underground localities. A slight frothy flake arose as the wind blew along the pellucid waters; and many a dash of spray was blown into my face. The mighty superstructure of rock which rose above to an inconceivable height left only a narrow opening—but where we stood, there was a large margin of strand. On all sides were capes and promontories and enormous cliffs, partially worn by the eternal breaking of the waves, through countless ages! And as I gazed from side to side, the mighty rocks faded away like a fleecy film of cloud.

It was in reality an ocean, with all the usual characteristics of an inland sea, only horribly wild—so rigid, cold and savage.

One thing startled and puzzled me greatly. How was it that I was able to look upon that vast sheet of water instead of being plunged in utter darkness? The vast landscape before me was lit up like day. But there was wanting the dazzling brilliancy, the splendid irradiation of the sun; the pale cold illumination of the moon; the brightness of the stars. The illuminating power in this subterranean region, from its trembling and Rickering character, its clear dry whiteness, the very slight elevation of its temperature, its great superiority to that of the moon, was evidently electric; something in the nature of the aurora borealis, only that its phenomena were constant, and able to light up the whole of the ocean cavern.

The tremendous vault above our heads, the sky, so to speak, appeared to be composed of a conglomeration of nebulous vapors, in constant motion. I should originally have supposed that, under such an atmospheric pressure as must exist in that place, the evaporation of water could not really take place, and yet from the action of some physical law, which escaped my memory, there were heavy and dense clouds rolling along that mighty vault, partially concealing the roof. Electric currents produced astonishing play of light and shade in the distance, especially around the heavier clouds. Deep shadows were cast beneath, and then suddenly, between two clouds, there would come a ray of unusual beauty, and remarkable intensity. And yet it was not like the sun, for it gave no heat.

The effect was sad and excruciatingly melancholy. Instead of a noble firmament of blue, studded with stars, there was above me a heavy roof of granite, which seemed to crush me.

Gazing around, I began to think of the theory of the English captain who compared the earth to a vast hollow sphere in the interior of which the air is retained in a luminous state by means of atmospheric pressure, while two stars, Pluto and Proserpine, circled there in their mysterious orbits. After all, suppose the old fellow was right!

In truth, we were imprisoned—bound as it were, in a vast excavation. Its width it was impossible to make out; the shore, on either hand, widening rapidly until lost to sight; while its length was equally uncertain. A haze on the distant horizon bounded our view. As to its height, we could see that it must be many miles to the roof. Looking upward, it was impossible to discover where the stupendous roof began. The lowest of the clouds must have been floating at an elevation of two thousand yards, a height greater than that of terrestrial vapors, which circumstance was doubtless owing to the extreme density of the air.

I use the word "cavern" in order to give an idea of the place. I cannot describe its awful grandeur; human language fails to convey an idea of its savage sublimity. Whether this singular vacuum had or had not been caused by the sudden cooling of the earth when in a state of fusion, I could not say. I had read of most wonderful and gigantic caverns—but, none in any way like this.

The great grotto of Guachara, in Colombia, visited by the learned Humboldt; the vast and partially explored Mammoth Cave in Kentucky—what were these holes in the earth to that in which I stood in speechless admiration! with its vapory clouds, its electric light, and the mighty ocean slumbering in its bosom! Imagination, not description, can alone give an idea of the splendor and vastness of the cave.

I gazed at these marvels in profound silence. Words were utterly wanting to indicate the sensations of wonder I experienced. I seemed, as I stood upon that mysterious shore, as if I were some wandering inhabitant of a distant planet, present for the first time at the spectacle of some terrestrial phenomena belonging to another existence. To give body and existence to such new sensations would have required the coinage of new words—and here my feeble brain found itself wholly at fault. I looked on, I thought, I reflected, I admired, in a state of stupefaction not altogether unmingled with fear!

The unexpected spectacle restored some color to my pallid cheeks. I seemed to be actually getting better under the influence of this novelty. Moreover, the vivacity of the dense atmosphere reanimated my body by inflating my lungs with unaccustomed oxygen.

It will be readily conceived that after an imprisonment of forty-seven days, in a dark and miserable tunnel it was with infinite delight that I breathed this saline air. It was like the genial, reviving influence of the salt sea waves.

My uncle had already got over the first surprise.

With the Latin poet Horace his idea was that—

Not to admire is all the art I know,

To make man happy and to keep him so.

"Well," he said, after giving me time thoroughly to appreciate the marvels of this underground sea, "do you feel strong enough to walk up and down?"

"Certainly," was my ready answer, "nothing would give me greater pleasure."

"Well then, my boy," he said, "lean on my arm, and we will stroll along the beach."

I accepted his offer eagerly, and we began to walk along the shores of this extraordinary lake. To our left were abrupt rocks, piled one upon the other—a stupendous titanic pile; down their sides leaped innumerable cascades, which at last, becoming limpid and murmuring streams, were lost in the waters of the lake. Light vapors, which rose here and there, and floated in fleecy clouds from rock to rock, indicated hot springs, which also poured their superfluity into the vast reservoir at our feet.

Among them I recognized our old and faithful stream, the Hansbach, which, lost in that wild basin, seemed as if it had been flowing since the creation of the world.

"We shall miss our excellent friend," I remarked, with a deep sigh.

"Bah!" said my uncle testily, "what matters it? That or another, it is all the same."

I thought the remark ungrateful, and felt almost inclined to say so; but I forbore.

At this moment my attention was attracted by an unexpected spectacle. After we had gone about five hundred yards, we suddenly turned a steep promontory, and found ourselves close to a lofty forest! It consisted of straight trunks with tufted tops, in shape like parasols. The air seemed to have no effect upon these trees—which in spite of a tolerable breeze remained as still and motionless as if they had been petrified.

I hastened forward. I could find no name for these singular formations. Did they not belong to the two thousand and more known trees—or were we to make the discovery of a new growth? By no means. When we at last reached the forest, and stood beneath the trees, my surprise gave way to admiration.

In truth, I was simply in the presence of a very ordinary product of the earth, of singular and gigantic proportions. My uncle unhesitatingly called them by their real names.

"It is only," he said, in his coolest manner, "a forest of mushrooms."

On close examination I found that he was not mistaken. Judge of the development attained by this product of damp hot soils. I had heard that the Lycoperdon giganteum reaches nine feet in circumference, but here were white mushrooms, nearly forty feet high, and with tops of equal dimensions. They grew in countless thousands—the light could not make its way through their massive substance, and beneath them reigned a gloomy and mystic darkness.

Still I wished to go forward. The cold in the shades of this singular forest was intense. For nearly an hour we wandered about in this visible darkness. At length I left the spot, and once more returned to the shores of the lake, to light and comparative warmth.

But the amazing vegetation of subterraneous land was not confined to gigantic mushrooms. New wonders awaited us at every step. We had not gone many hundred yards, when we came upon a mighty group of other trees with discolored leaves—the common humble trees of Mother Earth, of an exorbitant and phenomenal size: lycopods a hundred feet high; flowering ferns as tall as pines; gigantic grasses!

"Astonishing, magnificent, splendid!" cried my uncle; "here we have before us the whole flora of the second period of the world, that of transition. Behold the humble plants of our gardens, which in the first ages of the world were mighty trees. Look around you, my dear Harry. No botanist ever before gazed on such a sight!"

My uncle's enthusiasm, always a little more than was required, was now excusable.

"You are right, Uncle," I remarked. "Providence appears to have designed the preservation in this vast and mysterious hothouse of antediluvian plants, to prove the sagacity of learned men in figuring them so marvelously on paper."

"Well said, my boy—very well said; it is indeed a mighty hothouse. But you would also be within the bounds of reason and common sense, if you added that it is also a vast menagerie."

I looked rather anxiously around. If the animals were as exaggerated as the plants, the matter would certainly be serious.

"A menagerie?"

"Doubtless. Look at the dust we are treading under foot—behold the bones with which the whole soil of the seashore is covered—"

"Bones," I replied, "yes, certainly, the bones of antediluvian animals."

I stooped down as I spoke, and picked up one or two singular remains, relics of a bygone age. It was easy to give a name to these gigantic bones, in some instances as big as trunks of trees.

"Here is, clearly, the lower jawbone of a mastodon," I cried, almost as warmly and enthusiastically as my uncle; "here are the molars of the Dinotherium; here is a leg bone which belonged to the Megatherium. You are right, Uncle, it is indeed a menagerie; for the mighty animals to which these bones once belonged, have lived and died on the shores of this subterranean sea, under the shadow of these plants. Look, yonder are whole skeletons—and yet—"

"And yet, nephew?" said my uncle, noticing that I suddenly came to a full stop.

"I do not understand the presence of such beasts in granite caverns, however vast and prodigious," was my reply.

"Why not?" said my uncle, with very much of his old professional impatience.

"Because it is well known that animal life only existed on earth during the secondary period, when the sedimentary soil was formed by the alluviums, and thus replaced the hot and burning rocks of the primitive age."

"I have listened to you earnestly and with patience, Harry, and I have a simple and clear answer to your objections: and that is, that this itself is a sedimentary soil."

"How can that be at such enormous depth from the surface of the earth?"

"The fact can be explained both simply and geologically. At a certain period, the earth consisted only of an elastic crust, liable to alternative upward and downward movements in virtue of the law of attraction. It is very probable that many a landslip took place in those days, and that large portions of sedimentary soil were cast into huge and mighty chasms."

"Quite possible," I dryly remarked. "But, Uncle, if these antediluvian animals formerly lived in these subterranean regions, what more likely than that one of these monsters may at this moment be concealed behind one of yonder mighty rocks."

As I spoke, I looked keenly around, examining with care every point of the horizon; but nothing alive appeared to exist on these deserted shores.

I now felt rather fatigued, and told my uncle so. The walk and excitement were too much for me in my weak state. I therefore seated myself at the end of a promontory, at the foot of which the waves broke in incessant rolls. I looked round a bay formed by projections of vast granitic rocks. At the extreme end was a little port protected by huge pyramids of stones. A brig and three or four schooners might have lain there with perfect ease. So natural did it seem, that every minute my imagination induced me to expect a vessel coming out under all sail and making for the open sea under the influence of a warm southerly breeze.

But the fantastic illusion never lasted more than a minute. We were the only living creatures in this subterranean world!

During certain periods there was an utter cessation of wind, when a silence deeper, more terrible than the silence of the desert fell upon these solitary and arid rocks—and seemed to hang like a leaden weight upon the waters of this singular ocean. I sought, amid the awful stillness, to penetrate through the distant fog, to tear down the veil which concealed the mysterious distance. What unspoken words were murmured by my trembling lips—what questions did I wish to ask and did not! Where did this sea end—to what did it lead? Should we ever be able to examine its distant shores?

But my uncle had no doubts about the matter. He was convinced that our enterprise would in the end be successful. For my part, I was in a state of painful indecision—I desired to embark on the journey and to succeed, and still I feared the result.

After we had passed an hour or more in silent contemplation of the wondrous spectacle, we rose and went down towards the bank on our way to the grotto, which I was not sorry to gain. After a slight repast, I sought refuge in slumber, and at length, after many and tedious struggles, sleep came over my weary eyes.