420 HYPOTHESIS OF TWO FLUIDS. 



electrometer are made to diverge by means of 

 an electrified stick of resin, they will collapse 

 on the approach of an excited glass tube ; when 

 all signs of electricity disappear as if annihi- 

 lated. Nothing could be more fallacious than 

 such experiments ; for I have often found, that 

 after the gold leaves were made to diverge by 

 excited glass, they expanded still farther on the 

 approach of excited wax, and vice versa. The 

 result is evidently modified by the degree of 

 friction employed, and by the quantity of elec- 

 tricity thus disengaged. 



It was long since observed by Dr. Watson, 

 that the rubber of a common electrical machine, 

 exhibited the same electricity in all respects as 

 that which had been produced by the friction of 

 sealing wax, sulphur, rosin, &c. and afterwards 

 by Canton, Franklin, Beccaria, and Wilson, that 

 whenever two vitreous bodies were equally elec- 

 trified they repelled each other, but when 

 unequally, they attracted each other ; and that 

 the same was true of resinous bodies. Dr. 

 Franklin also found, that when glass globes 

 were excited by friction, the spark was larger and 

 longer than when a sulphurous globe was used, 

 and made a louder noise ; from which he inferred 

 that the glass contained on its surface more elec- 

 tricity than sulphur ; he therefore denominated 

 that of the glass plus or positive, and that of the 

 sulphur negative terms which are now in ge- 

 neral use. 



