324 Theory of two Kinds of Eleftricity. [Book IT* 



of the vitreous electricity, and a fingle globular mafs 

 of light diftinguiHied the refmous kind. The hand or 

 body alfo, which approached the vitreous or glafTy 

 fubftance, when excited, appeared to receive the mat- 

 ter from the electric ; but when one of the refmous 

 kind was excited, the electrical matter appeared to pro- 

 ceed from the hand or other approaching body. 



Notwithftanding, however, the names by which thefe 

 different forms of electricity were diftinguifhed, as the 

 vitreous and refmous, it was at length difcovered, that 

 >the different phenomena depended rather upon the 

 furface, than upon the nature and compofition of the 

 electric j for a glafs tube, when the polifhed furface 

 was deflroyed, by being ground with emery, and be- 

 ing rubbed with a fmooth body, exhibited all the proofs 

 of the refmous electricity, as much as fulphur or feal- 

 ing wax ; yet afterwards, when it was greafcd and rub- 

 bed with a rough furface, it refumed its former pro- 

 perty. It feems, therefore, to be a rule, that the 

 imootheft of two bodies, upon friction, exhibits the 

 phenomena of the vitreous electricity, for baked wooden 

 cylinders with a fmooth rubber are refinoufly electri- 

 fied, but with a rubber of coarfe flannel exhibit the 

 appearances of the vitreous kind, and even polilhed 

 glafs will produce the phenomena of the rcfinous 

 electricity, if rubbed with the fmooth hair of a cat's 

 fkin. 



Amidft this embarraffing variety of experiments, 

 thofe philofophers who applied to this branch of fci- 

 ence, were eagerly employed in inventing theories to 

 account for thefe phenomena, and electricians are ftill 

 divided with rclpect to the caufe. 



The eld theory of vitreous and refmous electricity, 

 or two diftinct, pofitive, and active powers, which 

 equally and ftronely attract and condenfe each other, 



has 



