Roever — Geometrical Properties of Lines of Force. 291 



1. The system having electric charges of unlike signs 



corresponds to the case in which OP has ^ " > 



( left handed > 



rotation and P £> has a motion to the< ° > . Fig. 1. 



d left S ^ 



2. The system having electric charges of like signs 



corresponds to the case in which OP has ^ ^®^* handed > 



C right handed > 



rotation and P D has a motion to the < ^ > . Fij?. 2. 



C left 5 * 



Fig. 6. 



Fig. 6 shows the lines of force proceeding from a sys- 

 tem consisting of an electrified plane AB and an electrified 

 point O. 



