As we paced along, meditating, I became more sensibly impressed with the fact that our progress was down a rapid declination. The saline incrustations, fungi and stalagmites, rapidly changed in appearance, an endless variety of stony figures and vegetable cryptogams recurring successively before my eyes. They bore the shape of trees, shrubs, or animals, fixed and silent as statues: at least in my distorted condition of mind I could make out resemblances to many such familiar objects; the floor of the cavern became increasingly steeper, as was shown by the stalactites, which, hanging here and there from the invisible ceiling, made a decided angle with the floor, corresponding with a similar angle of the stalagmites below. Like an accompanying and encircling halo the ever present earth-light enveloped us, opening in front as we advanced, and vanishing in the rear. The sound of our footsteps gave back a peculiar, indescribable hollow echo, and our voices sounded ghost-like and unearthly, as if their origin was outside of our bodies, and at a distance. The peculiar resonance reminded me of noises reverberating in an empty cask or cistern. I was oppressed by an indescribable feeling of mystery and awe that grew deep and intense, until at last I could no longer bear the mental strain.
"Hold, hold," I shouted, or tried to shout, and stopped suddenly, for although I had cried aloud, no sound escaped my lips. Then from a distance—could I believe my senses?—from a distance as an echo, the cry came back in the tones of my own voice, "Hold, hold."
"Speak lower," said my guide, "speak very low, for now an effort such as you have made projects your voice far outside your body; the greater the exertion the farther away it appears."
I grasped him by the arm and said slowly, determinedly, and in a suppressed tone: "I have come far enough into the secret caverns of the earth, without knowing our destination; acquaint me now with the object of this mysterious journey, I demand, and at once relieve this sense of uncertainty; otherwise I shall go no farther."
"You are to proceed to the Sphere of Rest with me," he replied, "and in safety. Beyond that an Unknown Country lies, into which I have never ventured."
"You speak in enigmas; what is this Sphere of Rest? Where is it?"
"Your eyes have never seen anything similar; human philosophy has no conception of it, and I can not describe it," he said. "It is located in the body of the earth, and we will meet it about one thousand miles beyond the North Pole."
"But I am in Kentucky," I replied; "do you think that I propose to walk to the North Pole, man—if man you be; that unreached goal is thousands of miles away."
"True," he answered, "as you measure distance on the surface of the earth, and you could not walk it in years of time; but you are now twenty-five miles below the surface, and you must be aware that instead of becoming more weary as we proceed, you are now and have for some time been gaining strength. I would also call to your attention that you neither hunger nor thirst."
"Proceed," I said, "’t is useless to rebel; I am wholly in your power," and we resumed our journey, and rapidly went forward amid silences that were to me painful beyond description. We abruptly entered a cavern of crystal, every portion of which was of sparkling brilliancy, and as white as snow. The stalactites, stalagmites and fungi disappeared. I picked up a fragment of the bright material, tasted it, and found that it resembled pure salt. Monstrous, cubical crystals, a foot or more in diameter, stood out in bold relief, accumulations of them, as conglomerated masses, banked up here and there, making parts of great columnar cliffs, while in other formations the crystals were small, resembling in the aggregate masses of white sandstone.
"Is not this salt?" I asked.
"Yes; we are now in the dried bed of an underground lake."
"Dried bed?" I exclaimed; "a body of water sealed in the earth can not evaporate."
"It has not evaporated; at some remote period the water has been abstracted from the salt, and probably has escaped upon the surface of the earth as a fresh water spring."
"You contradict all laws of hydrostatics, as I understand that subject," I replied, "when you speak of abstracting water from a dissolved substance that is part of a liquid, and thus leaving the solids."
"Nevertheless this is a constant act of nature," said he; "how else can you rationally account for the great salt beds and other deposits of saline materials that exist hermetically sealed beneath the earth's surface?"
"I will confess that I have not given the subject much thought; I simply accept the usual explanation to the effect that salty seas have lost their water by evaporation, and afterward the salt formations, by some convulsions of nature, have been covered with earth, perhaps sinking by earthquake convulsions bodily into the earth."
"These explanations are examples of some of the erroneous views of scientific writers," he replied; "they are true only to a limited extent. The great beds of salt, deep in the earth, are usually accumulations left there by water that is drawn from brine lakes, from which the liberated water often escaped as pure spring water at the surface of the earth. It does not escape by evaporation, at least not until it reaches the earth's surface."