"Yes, when they observe the facts," he replied, "it is very simple. They can now tell, as I have before remarked, how Columbus stood the egg on end; however, given the problem before Columbus expounded it, they would probably have wandered as far from the true solution as the mountain with its edgewise layers of stone is from the disconnected artesian wells on a distant sea coast where the underground fresh and salt water in overlying currents and layers clash together. The explanation, of course, is simple. The brine is of greater specific gravity than the pure water; the pressure of the heavier fluid forces the lighter up in the tube. This action continues until, as you will see by this experiment, in the gradual diffusion of brine and pure water the salt is disseminated equally throughout the vessels, and the specific gravity of the mixed liquid becomes the same throughout, when the flow will cease. However, in the earth, where supplies are inexhaustible, the fountain flows unceasingly." CHAPTER XXIX. BEWARE OF BIOLOGY, THE SCIENCE OF THE LIFE OF MAN.[6] (The old man relates a story as an object lesson.) [6] The reader is invited to skip this chapter of horrors.--J. U. L. "But you have not lived up to the promise; you have evaded part of the bargain," I continued. "While you have certainly performed some curious experiments in physics which seem to be unique, yet, I am only an amateur in science, and your hydrostatic illustrations may be repetitions of investigations already recorded, that have escaped the attention of the scientific gentlemen to whom I have hitherto applied." "Man's mind is a creature of doubts and questions," he observed. "Answer one query, and others rise. His inner self is never satisfied, and you are not to blame for wishing for a sign, as all self-conscious conditions of your former existence compel. Now that I have brushed aside the more prominent questionings, you insist upon those omitted, and appeal to me to--" he hesitated. "To what?" I asked, curious to see if he had intuitively grasped my unspoken sentence. "To exhibit to you your own brain," he replied. "That is it exactly," I said; "you promised it, and you shall be held strictly to your bargain. You agreed to show me my own brain, and it seems evident that you have purposely evaded the promise." "That I have made the promise and deferred its completion can not be denied, but not by reason of an inability to fulfill the contract. I will admit that I purposely deferred the exhibition, hoping on your own account that you would forget the hasty promise. You would better release me from the promise; you do not know what you ask." "I believe that I ask more than you can perform," I answered, "and that you know it."