280 



ON ELECTRICAL CHARGES AND DISCHARGES. 



experiment 

 when two non- 

 conductors 

 charged with 

 opposite elec- 

 tricities come 

 together, the 

 electricities dis' 

 appear. 



But it is not 

 destroyed. 



presents itself in this branch of electrical science, is the fol- 

 lowing. When two insulating bodies, or one insulating and 

 one conducting body, the surfaces of which are endued with 

 opposite electricities, come to be applied to each other by 

 then- surfaces, the electricity of both seems to disappear. 

 We no longer find any signs of it, or at least if any sign of 

 either kind of electricity remain, they may easily be deprived 

 of this surplus: but then if we endeavour to separate these 

 two bodies, we find, that they adhere together, which proves, 

 that all their electricity wa^ not really destroyed; and if we 

 overcome this resistance, and actually separate them, we 

 shall find, that each of l^hess bodies again exhibits signs of - 

 that kind of electricity, which it possessed before'they were _ 

 brought together. These phenomena however are not to be 

 observed in all their simplicity, except with insulating bo- 

 dies of a texture sufficiently thin tp be incapable of an elecr 

 trie charge; and such as have a kind of communication be^- 

 tween their surfaces, as with two ribands for instance, or 

 two silk stockings, or one of these and a piece of Insulated 

 tin foil. I shall not here enter into the particulars of these 

 experiments, which may be seen in Priestley's History of 

 Electricity, Mr, Syramer's communications to the Royal 

 Society, Mr. Cigna's paper in the 3d vol. of Miscellanies of 

 the Royal Society of Turin, &c. 

 Only a particu- Before I introduce this fact into the examination, that 

 lar case of an constitutes the principal object of this paper, it may not be 

 generallaw^*^ amiss to show, that it is merely a consequence of the known 

 principles of electricity, a particular case of a law, the gene- 

 rality of which is at present acknowledged. 

 The thinner ^^ ^^ known, that one kind of electricity is capable of be- 



the interposed jng so much the more condensed on a surface in proportion 

 the ^® ^^^ proximity of another surface endued with the con- 

 trary electricity, the attraction between the two kinds of 

 electricity in this case surmounting with more advantage the 

 repulsive power, which opposes this condensation in each 

 kind of electricity. It is known likewise, that for this rea- 

 son the coatings of ^ Leyden phial a i acquire much 

 greater quantities of electricity than bpdies of equal surfa- 

 ces electrified in the air ; and it is a pract.cal truth long 

 known, and depending on the same principle, that the 



strong' 

 opposite elec 

 tricities. 



I-eyden phiah 



