THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL. 



31'' JULY 1823. 



B 



I. All Essay 07i the Qiiestioji, Whether there be two Electrical 



Fluids according to Du Faye, or one according to Franklin. 



By Robert Hare, M.D. Professor of Chemistry in the 



University of Pennsylvania*. 



Y those who allege the existence of two electrical fluids, 

 much stress has been laid on the fact, that light bodies, 

 when negatively electrified, separate from each other no less 

 than when in the opposite state. The absence and presence 

 of a fluid cannot, it is said, have the same effect of producing 

 repulsion. To this it has been answered, that the separation 

 of such light bodies is not the effect of repulsion, but of an at- 

 traction between them and the surrounding medium ; which 

 must equally ensue whether they be electi'ified minus or plus : 

 since in either case that diversity of electrical excitement be- 

 tween them and the surrounding medium arises, which is al- 

 ways productive of attraction. 



In support of this view of the question I propose to make 

 a few observations. In an electroscope with moveable coat- 

 ings, like the galvanometer of Mr. Pepysf, the divergence of 

 the leaves is facilitated in proportion as the coatings are 

 approximated to them, whether the excitement be resinous or 

 vitreous. In this case it must be admitted that there is an 

 attraction between the coatings and the leaves ; for, were re- 

 pulsion between the leaves tlie cause of their divergence, the 

 approach of the coatings would not increase it. 



It may however be supposed, that the repulsion between 

 the similarly excited leaves, being counterbalanced, more or 

 less, in all cases, by die electric tension of the surrounding 

 medium, the coatings may permit the electric fluid to re- 

 cede through them with greater facility, and thus lessen the 

 electric tension in the direction in which they are situated. 



* Communicated by the Author. f See Phil. Mag., vol. x. p. 38. 



Vol. 62. No. 303. July 1823. A 2 Were 



