Ordinary and Voltaic Electric Fluids. 179 



surface of the cylinder as rapidly as it was received on the 

 outer, as is the case in charging a Leyden jar, a very different 

 condition would have been the result, polarization would have 

 been complete throughout the whole thickness of the cylinder*. 

 It is this state of unrelieved polarization which is required at 

 all times to render electricity sensible; thus in subjecting a 

 tourmalin to the action of heat, or in the excitation of any 

 electric, the fracture of crystals, &c. &c. When electricity is 

 developed it is necessary that each opposing surface should 

 possess an electrical condition of the same kind, or no deve- 

 lopment of free electricity will ensue, and no attraction of 

 light bodies or other sensible effect will be produced. See figs. 

 1 and 2. 



There is another kind of polarization alluded to in my 

 former papers, which increases tension in all modifications of 

 the electric fluid, which I have termed the " reciprocal " po- 

 larization. This occurs in all cases where one polarized body 

 is so placed in the vicinity of a second that the force which 

 each exerts shall mutually assist in exalting the electric con- 

 dition of the other. We have an exemplification of this power 

 exhibited in the experiment of the six jars described in my 

 former paper, where the discharge from the sixth to the first 

 will pass six times as far as from any single jar; also in the 

 combinations of a considerable number of pairs of plates in a 

 voltaic series, and in all magnetic and electro-magnetic phe- 

 nomena. 



Concluding Observations. 



That the tendency of all accumulations of electric fluid, in 

 obedience to the law of " universal equilibrium," is to become 

 dissipated and equally distributed amongst surrounding bodies, 

 which distribution is alone prevented by the interposition of 

 insulating media or electrics. 



By the separation or removal of a duly insulated accumu- 

 lation from its opposing force it assumes the condition of "free 

 charge," and so long as no body or bodies of equal magnitude 



* In charging a Leyden jar or battery, we find that so long as the charge 

 received within has force enough to continually render more and more 

 negative the outer coating, the two forces to a certain extent neutralize 

 each other j but so soon as this ceases, an electrometer (in connexion with 

 the internal) rises rapidly, and displays the augmentation of free fluid for 

 every spark which is added. 



Fig. 1. 

 p n p n p n p n p p 



OOOOOOOOOO free- 

 Fig. 2. 



pnpnpnpnpn 



OOOOOOOOOO neutral. 



N2 



