Granting this to be true, I concluded that I had not only a philosophical but a mathematical problem to solve. I, however, never met any one having any information on this latter point, nor in my readings did I find any allusion to the possibility of ascertaining the depth below the surface of any concealed stream or mineral. On the contrary, I found the general impression to be that the whole thing was a superstition of ignorant minds. The doubters frequently met me, and with some show of reason, with this personal argument: "I cannot believe this thing, because the switch does not turn in my hand." It is quite true that every hand does not have the power of giving the motion to the switch; but this does not disprove the fact of its turning. I have heard that the evidence of one man who heard a bell is worth that of a dozen who did not hear it. The testimony is, therefore, to my mind, clearly in favor of the "dowsers." All men are not the same conductors of electricity. I have known persons who could light the gas by running across the floor, rubbing their feet upon the carpet, and pointing a finger at the jet. I never saw this done, but I have no doubt that there are many who can do it, and also many who cannot. Now, although the switch may not turn in the hands of all, this is no proof that the current producing the movement does not pass through the persons just the same--the effect is only less perceptible in some, than in others. I had made a very large number of experiments, from time to time, before I had an opportunity to make one which satisfied me that I was on the right track. I had in these experiments exploded the superstition of the "witch-hazel," and learned that peach, apple, willow, dog-wood, beech, maple, iron, steel, copper--in fact, that even an old barrel hoop possessed all of its virtues, and so concluded that after all this relic of the necromancer's art of former days was a very simple matter, if we could but find the clue to it. A few years ago it happened that I wanted to get water at a place called Coloma, upon the Chicago, Michigan & Lake Shore Railroad, of which I was then chief engineer. I concluded to test my electric theory here. I found that it was necessary to dig a well upon the depot grounds--the point was to see if I could find water where I needed a tank. I took a switch and found water near the desired spot; then, with my theory in view, I made a second experiment. I bought four ink bottles, adjusted them to a pair of wooden sandals, which I fastened to my feet. Thus insulated, I walked over the ground, my switch in hand, but, as I had anticipated, there was no movement--the diviner's rod was powerless. I therefore assume that I am right in ascribing the phenomenon to electricity. I continued my experiments, having yet the mathematical point unsettled. Upon walking over the ground again and again, I found that the switch commenced always to turn at the same places, equally