80 ELEMENTS OF STATIC ELECTRICITY. 



This construction for the outer coatings makes them 

 durable, gives the jars a firm attachment, and adds 

 greatly to the neatness and beauty of the instrument. 



The E. M. F. of a Leyden battery is the same as that 

 of a single jar having the same amount of coated sur- 

 face. There can be no increase of intensity from any 

 special arrangement of the jars, as such a battery is 

 merely an accumulator, and not a generator "of electric- 



Fig. 22 Leyden Battery. 



ity. But when great E. M. F. is required it is generally 

 more convenient to use a battery than a single jar of 

 equal energy. And, in case of fracture from an over- 

 charge, a small jar can be replaced at less expense than 

 a larger one. 



In charging or discharging a battery, it is immaterial 

 which jar is selected : for all the inner coatings being 

 connected together, as well as all the outer coatings, 

 each is practically the same as a single coating of equal 



