Roever — Geometrical Properties of Lines of Force. 291 



1. The system havino; electric charges of unlike signs 



1 ^ ^1 - • I- I. r\m. fright handed 



corresponds to the case in which UJ^ has < " , , , 



C left handed 



rotation and P D has a motion to the < ,°^ i . Fig. 1. 



C left ) 



2. The system having electric charges of like signs 



corresponds to the case in which OP has s , , , f 



C right handed > 



rotation and P Z) has a motion to the < ,^, 



I left 



Fig. 2. 



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. 



