14 Chant — Experimental Investigation into the 



By referring to Table I, it will be seen that for every fre- 

 quency mentioned there gold and silver leaf are decidedly 

 thinner than the " skin " as there given ; while, in the case of 

 the lowest frequency (that of the cylinders), beside the gold 

 and the silver leaf, the metallic portion of cylinders numbered 

 11, 12, 13, 14 and 16 was thinner than the calculated " skin." 

 One would expect, therefore, that if the efficiency of the 

 oscillator depends on the thickness of the metal constituting 

 it, that dependence would manifest itself in the use of these 

 cylinders ; but extended and careful observation failed to 

 detect any evidence whatsoever of such an effect. 



The manner of experimenting was as follows : The cylinders 

 were placed in position in the zinc reflector, and the connec- 

 tions and sparking-distance carefully adjusted. Then the 

 magnetized detector was hung in the other reflector, which 

 was placed directly before the first reflector with a certain dis- 

 tance (usually 30 cms at first) between the focal lines of the two. 

 The key was then depressed while the pendulum made ten 

 swings, after which the detector was placed in its pocket 

 behind the magnetometer and the change noted in the scale 

 reading. The detector was then magnetized again and the 

 same work performed with the mirrors at a greater distance 

 apart. This was continued until readings at a sufficient num- 

 ber of distances had been secured. Then another pair of 

 cylinders was taken and a similar set of readings obtained. 



Rutherford reported that in his experiments no difference 

 could be detected whether the first semi-oscillation in the 

 receiver tended to magnetize the core or the reverse, but in 

 my experiments this w T as very evident. For instance, on put- 

 ting the detector in place at 30 cms from the oscillator, a scale 

 reading of 57 mm was obtained. Next, after re-magnetizing, 

 the detector was hung up so that the face presented to the 

 oscillator was the reverse of that in the former case ; in other 

 words, if the detector were now raised out of its mercury 

 cups, turned through 180° about its axis and then dropped into 

 its cups again, its first position would have been recovered. 

 With the detector in this second position a deflection of but 

 37 mm was obtained. The oscillator is very dead-beat, and 

 with the detector in the first position, the first (and greatest) 

 pulse received by it was in the direction to demagnetize the 

 core ; in the second position this first pulse was in the opposite 

 direction in the helix, and the total resulting demagnetization 

 was not so great. This difference in reading gradually dimin- 

 ished as the detector was withdrawn from the oscillator, and 

 at about 60 cms it disappeared. In Table III is given a series of 

 readings at distances between 30 and 90 cms , the two positions 

 of the detector being denoted by 1 and 2. 



