274 On the Alleged Luminosity of the Magnetic Field. 



More important was the possibility of indications being 

 afforded by the act of magnetization and demagnetization, 

 which might give notice to the observer and suggest to the 

 imagination the conversion of an illusion into a fancied reality. 



Of these indications the so-called " magnetic tick " at once 

 suggested itself. Knowing precisely what to listen for, and 

 therefore more keenly alive to the sound than Mr. Smith, 

 who presumably knew nothing of this molecular crepitation, 

 I failed to detect the faintest sound on the "making " of the 

 circuit; and a barely audible tick on "breaking" contact 

 was heard only when my ear was in close contact with the 

 magnet or its support. This was due to the massive cha- 

 racter of the magnet and stand, which also prevented any 

 other discernible movement when the magnet was excited. 

 Further, I satisfied myself that, at the distance at which 

 Mr. Smith stood from the magnet, it was impossible to 

 discover when the circuit was completed or interrupted by 

 the attraction of any magnetic substance about one's body ; 

 as a precaution, however, Mr. Smith emptied his pockets 

 beforehand. At the same time it is quite possible a skilful 

 operator, bent upon deceiving us, might be able to detect the 

 moment of magnetization and demagnetization by feeling the 

 movement of a concealed compass-needle. Against this hy- 

 pothesis must be placed the fact that no information was given 

 to Mr. Smith beforehand of the nature of the experiment; and 

 he had no object to serve by professing to see what he really 

 did not see. Ultimately all scientific observation rests upon 

 the good faith of the observers; and there was nothing to 

 arouse the smallest suspicion of the good faith of the observer 

 in the present instance. 



Similar experiments were made on another evening with 

 the boy Wells, with fairly satisfactory results. In the case 

 of Wells the luminosity, from his description, must have 

 appeared to be brighter and larger ; and on the interruption 

 of the circuit it was not instantly extinguished, but rapidly 

 died away*; his frequent exclamation on breaking the cur- 

 rent was " Oh, you are spoiling it." 



Wells was also tried in the dark chamber with two permanent 

 horseshoe magnets, and saw the luminosity clearly on both. 

 Unknown to Wells, I silently changed the position of the two 

 magnets; he at once detected where they were placed. Holding 

 one of the magnets in my hand, Wells told me correctly 

 whether I moved the magnet up or down or held it stationary; 

 this was repeatedly tried with success. In this case the poles 



* There was a considerable amount of residual magnetism in the elec- 

 tromagnet. 



