t 1049 ] 
"XLIX. Obfervations and Experiments tending to confirm. 
Dr. Ingenhoufz’s Theory of the Eleclrophorus ; and to 
Jhew the Impermeability of Glafs to Electric Fluid. 
By William Henly, F. R. .S'. 
Read July 9> TT^R, franklin has obferved, “ That 
“ there is a great quantity of the elec- 
“ trical fire in glafs ; that what it has it holds ; and that 
“ it has as much as it can hold : that what is already in 
“ it refufes, or ftrongly repels any additional quantity : 
“ that when an additional quantity is applied to one fur- 
“ face of a phial (for in fiance, by the atmofphere of an 
“ excited tube) a quantity is repelled or driven out of the 
“ inner furface of that fide into the veffel, returning 
11 again into its pores, when the excited tube with its at- 
u mofphere is withdrawn ; and that the particles of that 
K atmofphere do not themfelves pafs through the glafs.” 
The following experiments, I think, remarkably il- 
luftrate this, by fhewing that bodies are very differently 
Vol. LXVIII. 6 P affected 
