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author had not been able to say some- 

 thing about the Tesla motor. The first 

 form was hardly a practical alternating 

 motor, because it required three leads ; 

 and if a third lead was run, a direct cur- 

 rent might as well be used, with motors 

 which it was known could work efficiently. 

 But he thought that he had heard some- 

 thing about a lagging transformer, and 

 he should like to know more. The 

 author had called the Mordey alternator 

 an iron- clad machine. He considered 

 the word iron-clad a bad one to use. It 

 was employed some time ago to denote a 

 machine in which the iron was wrapped 

 round the copper ; the idea was that a 

 line integral of the magnetic force of 

 more ihan 0.4 n time the ampere turns 

 could somehow be obtained ; but that 

 fallacy had been dropped, and it was a 

 pity to use the word for the Mordey 

 machine, where the only object was to 

 get the whole field through one exciting 

 coil. The fault of the Kennedy machine, 

 as far as it had any, was the want of ven- 

 tilation. One of the great beauties of the 



