t 121 3 
IX. Obfervations on the Manner in which G/afs is charged with 
the eledlric Fluid , and difcharged. By Edward Whitaker 
Gray, M. D. F. R. S. , 
Read January 17, 1788. 
D R. Franklin, in various parts of the firft volume 
of his Experiments and Obfervations, aflerts, That 
the natural quantity of eleftric fluid in glafs cannot be 
increafed or decreafed ; and that it is impoflible to add any 
to one furface of a plate or jar, unlefs an equal quantity be, at 
the lame time, given out from the other furface *. This error 
has been adopted by fucceeding eleftricians ; among others, by 
the late Mr. Henly, who in one of his lafl: Papers, printed 
in the Philofopliical Tranfa&ions for the year 1777, has 
the following words : 44 According to Dr. Franklin’s theory, 
44 the fame quantity of the electric matter which is thrown 
44 upon one of the furfaces of glafs, in the operation of charg- 
44 ing it, is at the fame time repelled or driven out from the other 
“ furface; and thus one of the furfaces becomes charged plus, 
46 the other minus; and that this is really the cafe is, I 
44 think, fatisfadtorily proved, See. -f.” 
Becc ari A alfo has adopted the fame opinion, faying, “ That 
*( a quantity of excelfive fire cannot be introduced into one 
* “ The quantity proportioned to glafs it flrongly and obftinarely retain?, and 
“ will have neither more nor lefs.” Experiments and Obfervations, Vol. I. p. 26 . 
See alfo p. 75 81. et alibi. 
-j- Philosophical Tran factions, Vol. LXVII. p. iOO. 
Vol. LXXVI 1 I. R 
“ furface, 
