Page:A history of the theories of aether and electricity. Whittacker E.T. (1910).pdf/247

 and

By aid of these and the similar equations with the suffixes 2, 3, 4 the equation for the ponderomotive force may be transformed into the equation

But this is the equation which we should have obtained had we set out from the following assumptions: that the ponderomotive force between two current-elements is the resultant of the force between the positive charge in ds and the positive charge in ds&prime;, of the force between the positive charge in ds and the negative charge in ds&prime;, etc.; and that any two electrified particles of charges e and e&prime;, whose distance apart is r, repel each other with a force of magnitude

Two such charges would, of course, also cxert on each other an electrostatic repulsion, whose magnitude in these units would be ee&prime;c2/r2, where c denotes a constant of the dimensions of a velocity, whose value is approximately 3 x 1010 cm./sec. So that on these assumptions the total repellent force would be