GEOMETRICAL CONSTRUCTIONS OF THE LINES 

 OF FORCE PROCEEDING FROM 

 (a) TWO PARALLEL ELECTRIFIED LINES, 

 (&) TWO ELECTRIFIED POINTS.* 



Wm. H. Roever. 



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

 a system consisting of two parallel electrified lineSy is the locus 

 of the intersection of two straight lines^ rotating in the same 

 plane about these two parallel lines as axes, with uniform but 

 different angular velocities. 



The number of lines of force proceeding from an electrified 

 point having a charge dm is Airdm. The number proceed- 

 ing from an electrified straight line, made up of an infinite 

 number of points, is 47rm = ^irXl, in which I is the length of 

 the line, and X the charge per unit length. The mass or 

 charge included between two planes perpendicular to the 

 electrified line and separated by a distance I \s XI = m. The 

 flow of force between these two planes is ^irm; and if we 

 pass through the electrified line 47rm planes equally spaced, 

 each of the 47rm dihedral angles thus determined constitutes 

 an orthogonal tube in which the flow of force is unity. The 

 flow of force corresponding to an angle o) is then 



n = 4^'irm — = 2m(u. 

 27r 



Read before Tbe Academy of Science of St. Louis, April 6, 1896. 



(201) 



