ELECTRIC GENERATORS. 119 



The surfaces of the plates, on which the carriers and 

 inductors are mounted, assume the same potential as 

 the carriers and inductors attached to them, while their 

 opposite surfaces have the reverse. Opposite parts of 

 the same surface are also in opposite electric states : the 

 section L M H, for instance, having a potential oppo- 

 site to that of V M K; change of potential on these 

 surfaces following that of the carriers and inductors, 

 already described. 



It will be noticed that the office of the brushes, E and 

 F, is the reverse of that of H and F". E and F generate 

 by friction, while H and V discharge by contact. And, 

 while the combs, K and L, aid in creating a difference 

 of potential, the combs, H and F", aid in restoring equi- 

 librium. 



When the difference of potential between the inner 

 coatings of the jars becomes sufficient to overcome the 

 resistance of the air, a discharge from the inner coating 

 of D to that of C takes place between the terminals of 

 the sliding electrodes R and P ; and, at the same 

 instant, a discharge from the outer coatings takes place 

 through the switch and connections, from to D, to 

 restore equilibrium between them, and thus complete 

 the circuit. 



A spark and snap, from the resistance of the air, 

 accompanies the discharge between the inner coatings ; 

 and the same will occur between the outer coatings if 

 the switch is open ; but, if closed, the discharge takes 

 place silently. The plates and other parts being, at the 

 same instant, relieved of strain, there is a restoration of 

 equilibrium in the whole machine. 



The above explanation applies to the machine when 

 it is put in operation from a state of absolute rest ; but 



