THE THEORY OF THE DYNAMO 235 



making it any other shape. Indeed, currents could be more thoroughly 

 eliminated by dividing up the cross-section than by making it of a 

 very elongated form. 



[Discussion by Professor Elihu Thomson.] 



I do not like to rise so often, but I think there is some misapprehen- 

 sion. I have not said anything about large masses of iron. There are 

 the same masses of iron in my method as in any other. The only 

 question is as to making them round or elongated. Of course by 

 dividing this core up it becomes similar to a core of the Euhmkorff 

 coil, and the currents change very rapidly. From Professor Sylvanus 

 Thompson's remarks, I thought that that was desirable. One cannot 

 say that the current is transferred from the core to the wires outside. 

 The same current might take place, and, if the resistances are the 

 same, would take place in the wires outside in both cases. By lengthen- 

 ing the time of action one decreases the electro-motive force or de- 

 creases the external current. If the time is ten minutes one would 

 have one electro-motive force for the external current: if it is five 

 minutes, the electro-motive force would be somewhere near twice as 

 great as before, the whole quantity of electricity passing being the same 

 in both cases. 



