8 



SCWJVCU. 



[Vol. VIII , No. 178 



for he had only a choice between two things, one 

 of which was right and the other wrong. The 

 number of correct answers above one-half the total 

 number of answers would measure the magnetic 

 sensibility. 



Experimenting in this way, we were surprised 

 to find that considerably more than one-half the 

 answers were correct. Apparently the magnetic 

 sense was there. But it was soon observed that 

 we more or less consciously judged by the sound 

 that the turning of the dynamo transmitted along 

 the wire, and thus to the magnet. When the at- 

 tention was once directed to this point, the doings 

 of the operator could be correctly told every time. 

 After many failures, we succeeded in eliminating 

 this sound by cutting the wires, and inserting one 

 end of each into a mercury-cup, and connecting 

 the other by a binding-screw with the cup. The 

 wires were suspended from the ceiling by silk 

 threads, and inserted freely in the mercury: in this 

 way the sound-vibrations were transmitted to the 

 mercury, and only very weakly taken up again by 

 the wire. This arrangement was inserted in the cir- 

 cuit once in the basement room, and again on the 

 sill of the window, as the wires passed the second 

 floor of the building. The turning of the dynamo 

 was thus rendered inaudible ; and for a time the re- 

 sults were negative, the number of correct answers 

 being just about one-half of the total number of 

 experiments. But soon the correct answers be- 

 came more and more frequent. This time 

 the indications were more subtle. As is well 

 known to physicists, the magnetization and de- 

 magnetization of a powerful magnet produce 

 a molecular crepitation throughout its mass, 

 which gives rise to a very faint but audible click. 

 It was this click, and not the magnetic sense, that 

 told us when the current was being turned on, and 

 when off. It is remarkable that we used this click 

 as an indication of the condition of the magiiet 

 long before we were distinctly conscious of its 

 existence. This click could not be heard every 

 time, but, with the attention sharply focused, 

 almost every time. But it will be objected, as the 

 click accompanied each 'change,' it could not 

 guide the judgment of the subject. This objection 

 would hold were it not that the click accompany- 

 ing demagnetization is much more pronounced 

 than that accompanying magnetization. In fact, 

 the latter could rarely, if ever, be distinctly heard. 

 These difficulties were obviated by a slight al- 

 teration in the mode of experimentation. At the 

 beginning of each experiment the current was off ; 

 at the signal of 'Change,' the current was either 

 turned on or left off. The subject had then simply to 

 decide whether, on the whole, something had been 

 going on duriag the experiment, or whether the 



dynamo had not been turned at all. In this way, 

 only the magnetization, and never the demagneti- 

 zation, occurred in the experiments, and the click 

 was thus avoided. Moreover, to completely guard 

 against the very slight click of magnetization, the 

 current was not made as formerly, by the closing 

 of a key ; but, with a key always closed, the 

 dynamo was turned with gradually increasing 

 speed. It is the suddenness of the magnetization 

 that produces the click. It is evident, that, as be- 

 fore, the chances of a correct guess are just one- 

 half. The opportunities for judging are perhaps 

 not as favorable when only one change is made, 

 but it is doubtful v/hether even this difference is 

 appreciable. It is this latter method that was iised 

 throughout the rest of the experiments. In all, 

 ten persons, all students in good health, were ex- 

 perimented upon, including Dr. Nuttall and the 

 writer. The results are given in the following 

 table : — 



Subject. 



J. J 



G. H. F. N 



M.S 



L. B 



C. F. H... 



D. B 



M. E.C... 

 W. H. B.. 

 E.C. S.... 

 fl. B. N... 



No. of correct 



answers by 



the action of 



chance. 



275 

 275 

 75 

 50 

 50 

 50 

 50 

 50 

 50 

 50 



Diver- 

 gence. 



+ 11 



+ 12 



+ 1 

 



- 3 



- 3 



This table makes it evident, that, in the case of 

 those experimented upon, no sensibility for a mag- 

 netic field existed. This stUl leaves the question 

 open, whether there may not be a morbid sensi- 

 bility for such an effect ; but it makes such a pos- 

 sibility less probable, because the sensibility for 

 a magnetic field ascribed to ' sensitives ' is so 

 intense, that some slight remnant of it might be 

 expected to exist in normal persons. It was in- 

 tended to test persons who were good hypnotic 

 subjects both in the normal and the hypnotic con- 

 ditions, but no opportunity offered itself. Our 

 conclusions refer only to the question of a normal 

 magnetic sense. 



On what ground the alleged magnetic phe- 

 nomena are to be explained is another and more 

 deUcate question : that the imagination is a pow- 

 erful and important factor is beyond doubt ; and 

 when, as is generally the case, morbidly sensitive 

 patients, especially hysterical girls, are experi- 

 mented upon, the merest trace of a suggestion, 

 unconsciously given, of the desired or expected 

 effect, is enough to bring about aU the phenomena 

 of ' transport,' etc., for which the magnet has 

 been held accountable. Only when tested under 



