"THE WALL DESCENDED PERPENDICULARLY TO SEEMINGLY INFINITE DEPTHS."
"The cycle of the periodic overflow is measured by great intervals," he said; "centuries are required to raise the level of the lake a fraction of an inch, and thousands of years may elapse before its surface will again reach the top of the adamantine wall. Then, governed by the law that attracts a liquid to itself, and heaps the teaspoon with liquid, the water of the quiet lake piles upon this narrow wall, forming a ledge along its summit. Finally the superimposed surface water gives way, and a skim of water pours over into the abyss."
He paused; I leaned over and meditated, for I had now accustomed myself to the situation.
"There is no bottom," I exclaimed.
"Upon the contrary," he answered, "the bottom is less than ten miles beneath us, and is a great funnel-shaped orifice, the neck of the funnel reaching first down and then upward from us diagonally toward the surface of the earth. Although the light by which we are enveloped is bright, yet it is deficient in penetrating power, and is not capable of giving the contour of objects even five miles away, hence the chasm seems bottomless, and the gulf measureless."
"Is it not natural to suppose that a mass of water like this great lake would overflow the barrier immediately, as soon as the surface reached the upper edge, for the pressure of the immense volume must be beyond calculation."
"No, for it is height, not expanse, which, as hydrostatic engineers understand, governs the pressure of water. A liquid column, one foot in width, would press against the retaining dam with the force of a body of the same liquid, the same depth, one thousand miles in extent. Then the decrease of gravity here permits the molecular attraction of the water's molecules to exert itself more forcibly than would be the case on the surface of the earth, and this holds the liquid mass together more firmly."
Fig. 27.