72 



Mr. W. Morris Jones on the most Effective 



o£ L 21 , caused by removing turns from the secondary coil, 

 is applied, the curves take the form shown by the broken 

 line. The curves show that if V , L 21 , and L x are constant, 

 the maximum secondary potential increases as k 2 diminishes. 



Fig-. 4. 



This result also might be anticipated from the theory. By 

 (1) the amplitude of the potential waves in the secondary 



coil is in this case proportional to — -i- -. For 



</\(l-m) 2 + 4;k 2 m\ 

 any value of k this expression has, when m = l— 2k 2 , a 



maximum value of , — -. Within the range of the 



present experiments this quantity increases as k diminishes. 



In fig. 5 the curve shows the variation of the maximum 

 tube-distance d with the primary capacit}^ GV In this 

 experiment the coils and their coupling coefficient were 

 kept constant, k 2 being 0*348 — nearly equal to the value 

 recommended by Drude. The curve shows a maximum 

 tube-distance near the value m = 0'3, i. e. at a primary 

 capacity much greater than the resonance value given 

 bv m=l. 



