don, and challenged to find beneath the soil of this field the very same plate which he had previously detected in Mr. Dilke's desk at the Adelphi; but, having nothing to guide him even to a guess, he was completely at fault. Mr. Dilke's impression was that he was not an impostor, but a sincere believer in his own power, as the "dowsers" of mining-districts seem unquestionably to be. The test of blindfolding the diviner, and then leading him about in different directions, so as to put him completely at fault in regard to his locality, is one that can be very readily applied, when the diviner is acting in good faith; but, as I shall show you in the next lecture, it requires very special precautions to blindfold a person who is determined to see; and, in some of the cases which seem to have stood this test, it seems not improbable that vision was not altogether precluded.
An additional reason for attributing the action of the divining-rod to the muscular movements called forth by a state of expectancy (perhaps not always consciously entertained) on the part of the performer seems to me to be furnished by the diversity of the powers that have been attributed to it; such as that of identifying murderers and indicating the direction of their flight, discovering the lost boundaries of lands, detecting the birthplace and parentage of foundlings, etc. The older writers do not in the least call in question the reality of the powers of the hazel-fork, but learnedly discuss whether they are due to natural or to diabolic agency. When in the last century the phenomena of electricity and magnetism became objects of scientific study, but had not yet been comprehended under the grasp of law, it was natural that those of the divining-rod should be referred to agencies so convenient, which seemed ready to account for anything otherwise unaccountable. But, since physicists and physiologists have come to agree that the moving power is furnished by nothing else than the muscles of the diviner, the only question that remains is. What calls forth its exercise? And the conclusive evidence I have given you that the definite oscillations of suspended bodies depend on involuntary movements unconsciously determined by states of expectancy, clearly points to the conclusion that we have in the supposed mystery of the divining-rod only another case of the same kind. It is well known that persons who are conversant with the geological structure of a district are often able to indicate with considerable certainty in what spot, and at what depth, water will be found; and men of less scientific knowledge, but of considerable practical experience, frequently arrive at a true conclusion on this point, without being able to assign reasons for their opinions. Exactly the same may be said in regard to the mineral structure of a mining-district; the course of a metallic vein being often correctly indicated by the shrewd guess of an observant workman, where the scientific reasoning of the mining-engineer altogether fails. It is an