Sir W. Harris on the Laws and Operation of Electrical Force. 69 



Symbols. 



Let C = electrical charge ; Q= quantity ; E = intensity, or elec- 

 trometer indication ; S = surface, B = boundary extension, or peri- 

 meter ; A = direct induction ; I = reflected induction ; F = force ; 

 D = distance. 



Formula. 



C a S, when S and B vary together. 

 C oc Q, J3 being constant, or equal 1 . 

 C oc \/S, B being constant, or equal 1 . 

 C a ->/B, S being constant, or equal 1 . 

 C oc ^/S . B, when S and B vary together. 



■" a g"^ (Q being constant), for all plane rectangular surfaces. 



E oc _ , S being constant, or equal 1. 

 B 



E oc i B being constant, or equal 1. 

 E a , when S and B varv together. 



Co Ve 



E a Q 2 , S being constant, or equal 1. 



r, Q 2 



Coc 



S 2 

 In square plates, C oc with side of square. 

 In circular plates, C a with diameter. 

 In globes, C a with diameter. 



A, or induction a S, all other things remaining the same. 

 The same for S, or reflected induction. 

 In circular plates, globes, and closed and open surfaces, 



Ea_;oras-. 



F (=E) oc Q 2 . 



F or E oc — , S being constant. 



Q 2 



Generally we have F a ^-. 



12. The author calculates from these laws of charge for circles and 

 globes a series of circular and globular measures of definite values, 

 taking the circular inch or globular inch as unity, and calling, after 

 Cavendish, a circular plate of an inch in diameter, charged to satu- 

 ration, a circular inch of electricity ; or otherwise charged to any 

 degree short of saturation, a circular inch of electricity under a given 

 intensity. In like manner he designates a globe of an inch in dia- 

 meter a globular inch of electricity. 



In the following Table are given the quantities of electricity con- 



