on certain Theoretical Opinions. 47 



endeavour to return to their natural state, if nothing be su- 

 peradded to them, it must be supposed that they have poles 

 capable of existing in two different positions. In one of these 

 positions, dissimilar poles coinciding, are neutralized ; while 

 in the other position, they are more remote, and consequently 

 capable of acting upon other matter. 



12. But I am unable to imagine any change which can ad- 

 mit of gradations of intensity, increasing with remoteness. 1 

 cannot figure to myself any reaction which increase of distance 

 would not lessen. Much less can I conceive that such ex- 

 tremes of intensity can be thus created, as those of which you 

 consider the existence as demonstrated. It may be suggested 

 that the change of polarity produced in particles by electrical 

 inductions, may arise from the forced approximation of reci- 

 procally repellent poles, so that the intensity of the inductive 

 force, and of their effort to return to their previous situation, 

 may be susceptible of the gradation which your electrical 

 doctrines require. But could the existence of such a re- 

 pellent force be consistent with the mutual cohesion which 

 appears almost universally to be a property of ponderable 

 particles ? I am aware that, agreeably to the ingenious hy- 

 pothesis of Mossotti*, repulsion is an inherent property of the 

 particles which we call ponderable; but then he assumes the 

 existence of an imponderable fluid to account for cohesion; 

 and for the necessity of such a fluid to account for induction 

 it is my ultimate object to contend. I would suggest that it 

 can hardly be expedient to ascribe the phenomena of electri- 

 city to the polarization of ponderable particles, unless it can 

 be shown, that if admitted, it would be competent to produce 

 all the known varieties of electric excitement, whether as to 

 its nature or energy. 



13. If I comprehend your theory, the opposite electrical 

 state induced on one side of a coated pane, when the other is 

 directly electrified, arises from an affection of the intervening 

 vitreous particles, by which a certain polar state caused on 

 one side of the pane, induces an opposite state on the other 

 side. Each vitreous particle having its poles severally in op- 

 posite states, they are arranged as magnetized iron filings in 

 lines ; so that alternately opposite poles are presented in such 

 a manner that of all one kind are exposed at one surface, 

 and all of the other kind at the other surface. Agreeably to 

 this or any other imaginable view of the subject, I cannot 

 avoid considering it inevitable that each particle must have 

 at least two poles. It seems to me that the idea of polarity 



* [See Scientific Memoirs, vol. i., p. 448. EDIT.] 



