Blcctrical flfceasuremcnt. 87 



answer. If we want a very strong current of 

 great volume, so to speak, for electric light or 

 power, and use a galvanic battery, we should 

 have to have cells of large surface and lower 

 resistance both inside and outside the cells. 



When dynamos are used they are so con- 

 structed that a given number of revolutions 

 per minute will give the right voltage. In 

 fact, the dynamo has to be built for the amount 

 of current that must be delivered through a 

 given resistance. The same holds good for a 

 dynamo as for a galvanic battery. If any one 

 factor is fixed, we must adapt the others to 

 that one in order to get the result we want. 

 There are many other units, but to introduce 

 them here would only confuse the reader. The 

 advanced student is referred to the text-books. 



With this much as a preliminary we are pre- 

 pared to take up the applications of electricity, 

 wlii eh to most people will be more interesting 

 than what has gone before. 



