"This is sarcasm," he replied; "you are as changeable as the winds of the earth's surface. Now as you are about to approach a part of our journey where fort.i.tude is necessary, behold, you waver as a little child might. Nerve yourself; the trials of the present require a steady mind, let the future care for itself; you can not recall the past."

I became attentive again; the depressing effects of that repulsive dream rapidly lifted, and wasted away, as I realized that I was a man, and was destined to see more than can be seen in the future of other mortals.

This elevation of my spirit was evidently understood by my guide. He turned to the lake, and pointing to its quiet bosom, remarked:

"For five hours we have journeyed over this sheet of water at the average rate of nine hundred miles an hour. At the time you threw the fragments of cloth overboard, we were traveling at a speed of not less than twenty miles per minute. You remember that some hours ago you criticised my a.s.sertion when I said that we would soon be near the axis of the earth beneath the North Pole, and now we are beyond that point, and are about six thousand miles from where we stood at that time."

"You must have your way," I replied; "I can not disprove your a.s.sertion, but were it not that I have pa.s.sed through so many marvelous experiences since first we met, I would question the reliability of your information."

My guide continued:

"The surface of this lake lies as a mirror beneath both the ocean and the land. The force effect that preserves the configuration of the ocean preserves the form of this also, but influences it to a less extent, and the two surfaces lie nearly parallel with each other, this one being one hundred and fifty miles beneath the surface of the earth. The sh.e.l.l of the earth above us is honeycombed by caverns in some places, in others it is compact, and yet, in most places, is impervious to water. At the farther extremity of the lake, a stratum of porous material extends through the s.p.a.ce intervening between the bottom of the ocean and this lake. By capillary attraction, a.s.sisted by gravitation, part of the water of the ocean is being transferred through this stratum to the underground cavity. The lake is slowly rising."

At this remark I interrupted him: "You say the water in the ocean is being slowly transferred down to this underground lake less by gravity than by capillarity."

"Yes."

"I believe that I have reason to question that statement, if you do not include the salt," I replied.

"Pray state your objections."

I answered: "Whether a tube be long or short, if it penetrate the bottom of a vessel of brine, and extend downward, the brine will flow into and out of it by reason of its weight."

"You mistake," he a.s.serted; "the attraction of the sides of the capillary tube, if the tube is long enough, will eventually separate the water from the salt, and at length a downward flow of water only will result."

I again expressed my incredulity.

"More than this, by perfectly natural laws the water that is freed from the tubes might again force itself upward perfectly fresh, to the surface of the earth--yes, under proper conditions, above the surface of the ocean."

"Do you take me for a fool?" I said. "Is it not self-evident that a fountain can not rise above its source?"

"It often does," he answered.

"You trifle with me," I said, acrimoniously.

"No," he replied; "I am telling you the truth. Have you never heard of what men call artesian wells?"

"Yes, and" (here I attempted in turn to become sarcastic) "have you never learned that they are caused by water flowing into crevices in uplands where layers of stone or of clay strata separated by sand or gravel slant upward. The water conducted thence by these channels afterwards springs up in the valleys to which it has been carried by means of the crevices in these strata, but it never rises above its source."

To my surprise he answered:

"This is another of man's scientific speculations, based on some facts, it is true, and now and then correct, but not invariably. The water of an artesian well on an elevated plane may flow into the earth from a creek, pond, or river, that is lower than the mouth of the well it feeds, and still it may spout into the air from either a near or distant elevation that is higher than its source."

"I can not admit the truth of this," I said; "I am willing to listen to reason, but such statements as these seem altogether absurd."

"As you please," he replied; "we will continue our journey."

INTERLUDE.--THE STORY INTERRUPTED.

CHAPTER XXVIII.

A CHALLENGE.--MY UNBIDDEN GUEST ACCEPTS IT.

The white-haired reader, in whom I had now become deeply interested, no longer an unwelcome stranger, suspended his reading, laid down his ma.n.u.script, and looking me in the face, asked:

"Are you a believer?"

"No," I promptly answered.

"What part of the narrative do you question?"

"All of it."

"Have you not already investigated some of the statements I previously made?" he queried.

"Yes," I said; "but you had not then given utterance to such preposterous expressions."

"Is not the truth, the truth?" he answered.

"You ask me to believe impossibilities," I replied.

"Name one."

"You yourself admit," I said warmly, "that you were incredulous, and shook your head when your guide a.s.serted that the bottom of the ocean might be as porous as a sieve, and still hold water. A fountain can not rise above its source."

"It often does, however," he replied.

"I do not believe you," I said boldly. "And, furthermore, I a.s.sert that you might as reasonably ask me to believe that I can see my own brain, as to accept your fiction regarding the production of light, miles below the surface of the earth."

"I can make your brain visible to you, and if you dare to accompany me, I will carry you beneath the surface of the earth and prove my other statement," he said. "Come!" He arose and grasped my arm.

I hesitated.

"You confess that you fear the journey."

I made no reply.

"Well, since you fear that method, I am ready to convince you of the facts by any rational course you may select, and if you wish to stake your entire argument on the general statement that a stream of water can not rise above its head, I will accept the challenge; but I insist that you do not divulge the nature of the experiment until, as you are directed, you make public my story."

"Of course a fluid can be pumped up," I sarcastically observed.

"However, I promise the secrecy you ask."