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was a great difference in samples in that 

 respect. He had made transformers 

 which would work with very high induc- 

 tion without heating. One of the most 

 important questions to settle was fre- 

 quency of alternation. It had been stated 

 that in America 16,000 alternations per 

 minute had been taken, and at Rome 

 5,000, and what should be made the 

 standard in England should be carefully 

 considered. In dynamo construction he 

 found that it was easier to make a ma- 

 chine giving a very few alternations. In 

 that way he could construct a larger 

 dynamo for the same amount of money, 

 and make it work more efficiently. The 

 first point to be settled was the number 

 of vibrations per second which could be 

 separated by the eye. Helmholtz, in his 

 " Sensations of Tone as a basis for the 

 Theory of Music," gave 24 per second. 

 Messrs. Crompton were going to try 

 some experiments to ascertain whether it 

 was possible to detect flickering in 100- 

 volt lamps with anything below 24 vibra- 

 tions per second. It was a pity that the 



