348 Reflections on the Inadequacij of the principal Hypotheses 



for supposing such states as plus and minus : they are scarcely 

 applicable to anv facts, and they perplex some ; the following 

 which I accidentally observed, affords an instance. A pair of 

 gilt pith-balls are suspended by gilt strings from a brass insu- 

 lated socket. When a stick of excited sulphur is brought in 

 contact with the socket, the balls diverge iicgati\ely. If the 

 contact of the sulphur and socket be continued without stirnng 

 the sulphur, the balls will nevertheless in some time come to- 

 gether. If now the sulphur be suddenly withdrawn, the balls 

 will separate to perliaps a greater distance t'lan before ; but they 

 have diverged v/ilh a contrary state of electricity, they are now 

 positive*. The first effect of the sulphur was, according to the 

 Franklinians, to deprive the balls and surrounding air of their 

 natural electricity, the balls then separated being negatively 

 electrified. At length still retaining the negative state, they 

 come together, the sulphur is then removed, and at the time 

 when the balls and air have lost even their natural portion of 

 electricity, they manifest tlie appearance of an excess ! 



V/ith regard to the position that the Leyden^ phial is under 

 the same circumstances after the discharge as before charging, 

 the following facts afford some doubts. Beccaria charged two 

 glass plates, each coated on one side onlv, and applied them 

 closely together witji the uncoated sides facing : the whole re- 

 sembling one coated charged plate. When a communication 

 was formed between both surfaces, an explosion took place, but 

 the plates cohered with great force. 



I coated a glass plate on cue side, within an inch of the edge, 

 thus leaving an uncoated margin all round. The uncoated side 

 opposite the foil was rubljcd with an amalgamated leather. When 

 the glass was well excited, 1 placed a corresponding metallic 

 coating, by its glass handle, on the surface of the plate, and, 

 by making my finger and thumb the circuit between the sur- 

 faces, I received a slight shock. By touching the metallic coat- 

 ing and raising it by its glass handle, a large spark was obtained : 

 and by continuing this proces;s, a considerable number- of 

 sparks were drawn, which for a long time seemed to increase in 

 strength. The same appea.rance but in a less degree may be 

 produced by charging the plate from an electric machine, and 

 afterwards using it as an electrophorus. Do not these experi- 

 ments indicate that after the discharge^ the natural state was 

 not resumed ? 



From all the preceding considerations it would appear, that 



* This experiment requires attention, and will not succeed in all states 

 •fthe weather. The same may be said of some of the forcf^oing experi- 

 ments. If two balls do not succeed one will in a less striking manner an- 

 swer. Its change 0/ state may be ascertained iu the usual manner. 



positive 



