ELECTRICAL APPARATUS. 



273 



the balls will cease. Again produce separation of contact, 

 and they will again diverge ; and thus, for a considerable 

 time, the alternate action will be kept up, even indeed for 

 days and weeks. Price, $0.75. 



Electrical Bells. (Fig. 296, previous page.) The electri- 

 cal bells furnish a pleasing illustration of the attraction and 

 repulsion of the electric matter. They are variously con- 

 structed, but the form exhibited in the figure is one of the 

 simplest. The two outer bells are suspended by brass 

 chains ; the middle bell and the two clappers by fine silk 

 threads. When the bells are attached to the conductor, 

 and the machine is turned very slowly, the fluid will pass 

 along the chains to the two outer bells, but will not pass 

 along the silk to the clappers and middle bell. Thus the 

 outer bells being charged with an extra quantity of electri- 

 city, will attract the clappers, but the moment they touch 

 the bells they become charged, and are repelled with such 

 force as to cause them to strike against the middle bell, on 

 which they deposit their electricity, and are again attracted. 

 By this means a constant ringing is kept up while the 

 machine is turned. From the inside of the middle bell a 

 brass chain passes to the table, for the purpose of convey- 

 ing away the fluid deposited on it by the clappers. 



Price, $2.00. 



Fig. 297. 



Set of two Electrical Bells. (Fig. 297.) 

 This is the simplest form of the experiment, 

 one of the bells communicating with the 

 prime conductor, and the other with the 

 ground ; they are made to ring by the alter- 

 nate blows of a small brass ball suspended 

 between them. Price, $1.25. 



Chime of five Bells. Fig. 298, next page, 

 represents a more elegant form of mounting 

 the electrical bells. It consists of a swelled 

 glass pillar, on the top of which is cemented a cap, bearing 

 a brass cross ; the four outer bells are affixed to the ends 

 of this by wires, and the clappers are suspended from the 

 middle by silk cords ; the middle bell communicates with 

 the ground by the mahogany foot which supports the 



