248 THE SCIENTIFIC PAPERS Of 



In the discussion of the Paper 



"ON ELECTRICAL RAILWAYS AND TRANSMISSION 



OF POWER BY ELECTRICITY," 



By MR. ALEXANDER SIEMENS, 



DR. C. W. SIEMENS, F.R.S.,* said he would only make a few 

 remarks that evening, and speak more at length when the discus- 

 sion was resumed next week. Professor Ayrton had remarked 

 that the dynamo machine would be superseded by the magneto 

 machine, or by a dynamo machine with a separate exciter, and he 

 confessed that he went a long way with him in his argument ; 

 indeed, last year he communicated a paper to the Royal Society in 

 which he showed certain defects in the dynamo machine, and sug- 

 gested certain remedies. The dynamo laboured under this defect, 

 that, with an increase of work, the power to overcome the resist- 

 ance diminished. The current produced -by the rotation of the 

 coils in the magnetic field had to excite the coils of the magnet 

 itself, and the current then passed on to the second machine or to 

 the light, to the place where the work was to be performed. Now 

 if that work should present increased resistance, the machine 

 which had to overcome it should increase in energy, whereas the 

 greater resistance caused a weakening of the current and a falling 

 off in the power of the magnets by which the current was pro- 

 duced, thus causing those fluctuations which were so troublesome 

 in electric lamps, but which, by different arrangements, had been 

 almost overcome, and would be entirely overcome by the aid of 

 further experience. It was quite true that in the City they were 

 working with dynamo machines having separate exciters, but the 

 dynamo machine could be so arranged that a portion only of the 

 current was set aside to excite its own magnet, and if that arrange- 

 ment were properly applied, he believed all the advantages of a 

 separate exciter could be secured with a single machine. The 

 subject especially before them, however, was the application of 



* Excerpt Journal of the Society of Arts, Vol. XXIX. 1880-81, p. 574, and 

 pp. 588, 589. 



