Part 13 (1/2)
”So you admit that the a.s.sertion governing the surfaces of liquids is true only when the liquids are connected from beneath. In other words, your thought is one-sided, as science thought often is.”
”Yes.”
[Ill.u.s.tration: FIG. 18. E, water surface. F, brine surface.]
”Now as to the beds of salt deep within the earth. You are also mistaken concerning their origin. The water of the ocean that runs through an open channel from the one side may flow into an underground lake, that by means of the contact action (suction) of the overlying and surrounding strata is being continually emptied of its water, but not its salt. Thus by absorption of water the brine of the lake becomes in time saturated, starting crystallization regularly over the floor and sides of the basin. Eventually the entire cavity is filled with salt, and a solid ma.s.s of rock salt remains. If, however, before the lake becomes solid, the brine supply is shut off by some natural cause as by salt crystals closing the pa.s.sage thereto, the underground lake is at last drained of its water, the salt crystallizing over the bottom, and upon the cliffs, leaving great crevices through the saline deposits, as chances to have been the case with the salt formations through which I pa.s.sed with my guide, and have recently described to you.”
”Even now I have my doubts as to the correctness of your explanations, especially concerning the liquid surfaces.”
”They are facts, however; liquids capable of being mixed, if connected by porous arches (bibulous paper is convenient for ill.u.s.trating by experiment) reverse the rule men have accepted to explain the phenomena of liquid equilibrium, for I repeat, the lighter one rushes into that which is heavier, and the surface of the heavier liquid rises. You can try the experiment with alcohol and water, taking precautions to prevent evaporation, or you can vary the experiment with solutions of various salts of different densities; the greater the difference in gravity between the two liquids, the more rapid will be the flow of the lighter one into the heavier, and after equilibrium, the greater will be the contrast in the final height of the resultant liquid surfaces.”
”Men will yet explain this effect by natural laws,” I said.
”Yes,” he answered; ”when they learn the facts; and they will then be able to solve certain phenomena connected with diffusion processes that they can not now understand. Did I not tell you that after the fact had been made plain it was easy to see how Columbus stood the egg on its end? What I have demonstrated by experiment is perhaps no new principle in hydrostatics. But I have applied it in a natural manner to the explanation of obscure natural phenomena, that men now seek unreasonable methods to explain.”
”You may proceed with your narrative. I accept that when certain liquids are connected, as you have shown, by means of porous substances, one will pa.s.s into the other, and the surface of the lighter liquid in this case will a.s.sume a position below that of the heavier.”
”You must also accept,” said he, ”that when solutions of salt are subjected to earth attraction, under proper conditions, the solids may by capillary attraction be left behind, and pure water finally pa.s.s through the porous medium. Were it not for this law, the only natural surface spring water on earth would be brine, for the superficial crust of the earth is filled with saline solutions. All the spring-fed rivers and lakes would also be salty and fetid with sulphur compounds, for at great depths brine and foul water are always present. Even in countries where all the water below the immediate surface of the earth is briny, the running springs, if of capillary origin, are pure and fresh. You may imagine how different this would be were it not for the law I have cited, for the whole earth's crust is permeated by brine and saline waters. Did your 'philosophy' never lead you to think of this?”
Continuing, my guest argued as follows: ”Do not lakes exist on the earth's surface into which rivers and streams flow, but which have no visible outlet? Are not such lakes saline, even though the source of supply is comparatively fresh? Has it never occurred to you to question whether capillarity a.s.sisted by surface evaporation (not evaporation only as men a.s.sert) is not separating the water of these lakes from the saline substances carried into them by the streams, thus producing brine lakes? Will not this action after a great length of time result in crystalline deposits over portions of the bottoms of such lakes, and ultimately produce a salt bed?”
”It is possible,” I replied.
”Not only possible, but probable. Not only probable, but true. Across the intervening brine strata above the salt crystals the surface rivers may flow, indeed, owing to differences in specific gravity the surface of the lake may be comparatively fresh, while in the quiet depths below, beds of salt crystals are forming, and between these extremes may rest strata after strata of saline solutions, decreasing in gravity towards the top.”
Then he took his ma.n.u.script, and continued to read in a clear, musical voice, while I sat a more contented listener than I had been previously.
I was not only confuted, but convinced. And I recalled the saying of Socrates, that no better fortune can happen a man than to be confuted in an error.
MY UNBIDDEN GUEST CONTINUES READING HIS Ma.n.u.sCRIPT.
CHAPTER XXI.
MY WEIGHT DISAPPEARING.
We halted suddenly, for we came unexpectedly to the edge of a precipice, twenty feet at least in depth.
”Let us jump down,” said my guide.
”That would be dangerous,” I answered; ”can not we descend at some point where it is not so deep?”
”No; the chasm stretches for miles across our path, and at this point we will meet with the least difficulty; besides, there is no danger. The specific gravity of our bodies is now so little that we could jump twice that distance with impunity.”