554 



ELECTRICAL ATTRACTION, 



electrified body. Fig. 302 B shows the mode of suspend- 

 ing the glass rod. The hand may be simply brought 

 near to one end of the excited glass rod, and the latter 

 will follow the hand as the cork in the previous experi- 

 ment, and may similarly be made to revolve. A long 



FIG. 302 (an. proj. ; A I, B % real size). 



stick of sealing-wax, made by fixing together two sticks 

 at the ends, when rubbed with flannel and similarly sus- 

 pended, may be set in rotatory motion by the hand or 

 any other non-electric body, for example, a piece of 

 wood, a metal spoon, a hammer, &c. 



For rotatory motion these bodies are best suspended by a thread 

 of untwisted silk or a horse hair ; with a common twisted thread 

 it takes too much time before a suspended body comes to rest. A 

 twisted thread may, however, be used by first holding the rod by the 

 middle after placing it in the bent wire, and then releasing it ; as 

 soon as the direction in which the thread turns the rod is seen, the 

 electrified body is quickly brought near the bar on the side opposite 

 to that in which it is moved by the thread, and it will now be 

 moved in a contrary direction by the electrical attraction. Without 

 this precaution the motion produced by electrical attraction could 

 not be distinguished from the motion produced by the twist of the 



