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had the advantage of having a single 

 current for the field magnet, and a single 

 current for the induced armature. He 

 would only say a word on the subject of 

 the speed of alternations. Why was it 

 that in America 16,000 alternations per 

 minute were used, and in Europe at the 

 greatest number of stations 5,000 ! One 

 reason was, that in America high-speed 

 machines were in favor, and in Europe 

 low speed. Another reason was that, in 

 America, the object aimed at was to get 

 the greatest output from the plant. 

 Those reasons were sufficient for having 

 high-speed alternations. Unless it was 

 wished to work in parallel, it could not 

 be doubted that working with the high- 

 est-speed alternations was best ; but for 

 working in parallel there could be no 

 doubt that the lowest speed was the 

 most easy mode. That was one reason 

 why the Qanz machines at Rome were so 

 suitable. In this country there was a 

 general belief that converters had an 

 efficiency of 95 or 96 per cent, on full 

 load ; but the greater number of con- 



