to verify your present sense faculty. This you must do as opportunities present, and with different devices, so that no question may arise as to what will follow when others repeat our experiments. To-morrow evening I will call again, but remember, you must not tell others of this experiment, nor show the devices to them." [Illustration: FIG. 23. A, brine. B, sand and brine mixed. C, sand and water.] "I have promised," I answered. He gathered his manuscript and departed, and I sat in meditation watching the mysterious fountain. As he had predicted, finally, after a long time, the flow slackened, and by morning, when I arose from my bed, the water had ceased to drip, and then I found it salty to the taste. The next evening he appeared as usual, and prepared to resume his reading, making no mention of the previous test of my faith. I interrupted him, however, by saying that I had observed that the sand had settled in the cylinder, and that in my opinion his experiment was not true to appearances, but was a deception, since the sand by its greater weight displaced the water, which escaped through the tube, where there was least resistance. "Ah," he said, "and so you refuse to believe your own eyesight, and are contriving to escape the deserved penalty; I will, however, acquiesce in your outspoken desire for further light, and repeat the experiment without using sand. But I tell you that mother earth, in the phenomena known as artesian wells, uses sand and clay, pools of mineral waters of different gravities, and running streams. The waters beneath the earth are under pressure, induced by such natural causes as I have presented you in miniature, the chief difference being that the supplies of both salt and fresh water are inexhaustible, and by natural combinations similar to what you have seen; the streams within the earth, if a pipe be thrust into them, may rise continuously, eternally, from a reservoir higher than the head. In addition, there are pressures of gases, and solutions of many salts, other than chloride of soda, that tend to favor the phenomenon. You are unduly incredulous, and you ask of me more than your right after staking your faith on an experiment of your own selection. You demand more of me even than nature often accomplishes in earth structure; but to-morrow night I will show you that this seemingly impossible feat is possible."