﻿Elect viral Resistance of Alloys. 607" 



wave -form of the current used was not known, but the 

 second term in the bracket was made small by using- wires 

 of small diameter. Were any skin effect present, only the 

 difference between that in lead and in the alloy would be 

 given by the experiment. 



For the same frequency the value of this term depends 

 on Z/E, and this is greatest for the pure metal, and hence 

 if fi=l, the skin effect, when it first becomes appreciable, 

 would make the alloy appear to decrease in resistance when 

 referred to copper or Jead as standard. 



All the coils in the bridge were made of wire 0*33 mm. in 

 diameter, formed after the manner given by Chaperon, by 

 first winding a definite number of turns in the right-handed 

 direction and then an equal number the opposite way. The 

 resistance of each was 3 ohms approximately ; the induction 

 in the arms by this method was rendered very small, but was 

 still large enough, with these low resistances, to oiye a flat 

 minimum in the telephone. With an ordinary set of coils 

 out of a resistance-box it. was impossible to obtain a balance. 

 In order to render the minimum sharper the method of 



