.V/A' ll'ILLIAM SIEMENS, F.R.S. 



4OI 



tin- number of incandescent lights which each machine will 

 sustain. Thut is perhaps of little importance to our present 

 I'iKjiiiry ; but in another column, to which I would draw par- 

 ticular attention, you have the relative effect per Ib. of copper wire 

 in the different machines, and the enormous difference in the 



TABLE OP PABTICULABS OP DYNAMO AND ALTERNATE CURRENT 

 MACHINES. 



values shows sufficiently what scope there is for the development 

 of the dynamo machine. For instance, in one machine, 1 Ib. of 

 copper produces only 17 watts, or units of electric energy ; and in 

 another the last which has been produced the effect is 48. 



VOL. Ill 



