GEOMETRICAL PROPERTIES OF THE LINES OF 

 FORCE PROCEEDING FROM 

 (a) A SYSTEM CONSISTING OF AN ELECTRI- 

 FIED PLANE AND AN ELECTRIFIED 

 LINE PARALLEL TO THE PLANE. 

 {b) A SYSTEM CONSISTING OF AN ELECTRI- 

 FIED PLANE AND AN ELECTRIFIED 

 POINT.* 



Wm. H. Roever. 



(a) The curve representing a line of force proceeding from 

 a system co7isisting of an electrified plane and an electrified 

 line parallel to the plane, is the locus of the intersection of 

 two straight lines having motions in a plane which is perpen- 

 dicidar to the electrified line; one line having a motion of 

 uniform rotation about the electrified line as an axis, and the 

 other a motion of uniform translation perpendicular to itself 

 and parallel to the electrified plane. 



The force at a distance r from an electrified straight line 



2X 

 whose charge is X per unit length is f = — . The flow of force 



2X 

 from a unit length of line is — X 27rr = 47rX. Hence the 



flow of force from a unit length of line between two planes 

 which intersect in the line and make an angle cu with each 

 other is 



iV= 47rX — = 2\a). 

 2'Tr 



The force at a finite distance from an infinite electrified plane 

 whose charge is a per unit area is jP= 27ra. Hence the flow 



* Read before The Academy of Science of St. Louis, December 7, 1896. 



(273) 



