220 



Trans. Acad. Sci. of St. Louis. 



through these points) in such a manner that the versines of 

 their angles of inclination to the plane of the axes both increase 

 or both decrease at uniform rates; also, that the charges on the 

 electrified points are, numerically, inversely proportional to 

 the rates of change of the versines. 



Equations (25) and (27) have the same form, and in this 

 case also the primed constants are interchanged. This shows 

 that the curve representing a line of force proceeding from a 

 system consisting of two electrified points, having charges of 

 the same algebraic sign, is the locus of the intersection of two 

 straight lines rotating in the same plane about parallel axes 

 (passing through these points), in such a manner that the 

 versine of the angle of inclination of one of the lines to 

 the plane of the axes, increases or decreases at a uniform rate, 

 while the versine of the angle of inclination to the plane of 

 the axes of the other line, decreases or increases at a uniform 

 rate ; also, that the charges on the electrified points are, 

 numerically, inversely proportional to the rates of change of 

 the versines. 



Fig. 8 shows the lines of force proceeding from a system 

 consisting of two electrified points A and A' having charges 



