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only part of the copper conductor con- 

 veying electricity was a thin shell or tube 

 on the outside. If that theory was true, 

 the lower the frequency, the greater 

 the efficiency of the conductor. Another 

 reason for less frequency was that meters 

 could work with greater accuracy. 



Professor George Forbes congratula- 

 ted the author on the many points of 

 interest he had brought forward, and 

 especially on the happy way in which he 

 had taken in hand the theoretical inves- 

 tigation of alternate-current machines. 

 He had been one of the first to discuss 

 the theory of continuous- current machines 

 in the proper fashion, and since he read 

 his paper on the subject before the 

 Institution two years ago, the progress 

 had been marked, so that now the design 

 of continuous-current machines was as 

 straightforward work as any mechanical 

 designs. He had taken up the subject of 

 alternate-current machines in the same 

 spirit. On the occasion when the author 

 read a paper on continuous-current 

 machines. Professor Forbes had occasion 



