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the flight fri Elion of the breath , as enables it to de- 
Aroy the ballance and overcome the ref fiance at the 
Jurface of the wood, in that part, where it is joined to 
the amber. 
Th t Leyden experiment depends alio upon a certain 
ballance , which obtains between the mediums at the 
oppoiite furfaces of the glafs, by the power of re- 
pulfion * : but this enquiry, being of a very exten- 
flve nature, would lead me too far for the bulinefs 
of a letter ; I mud therefore refer you to the works 
quoted laA. In feleddng the experiments above re- 
lated to prove ref fiance, I have purpofely confined 
myfelf to a few, and thofe fucli as appeared to be the 
mod Ample and mod worthy of attention. You 
will therefore do me the honor to examine, and 
confider carefully thefe experiments and obfervations, 
as I think they have fufficiently eflablijhed a ref (lance 
appertaining to bodies, independent of the grofs 
matter they contain : and that it arifes from the fame 
elajhc medium which we before proved to exift 
between the convex glafies. 
London Dec. 20, 1763. I am, &c. 
B. Wilfon. 
* The confideration of this experiment was particularly at- 
tended to, in a former work, by Dr. Hoadly and myfelf. Sec 
alfo the Phil. Tranf. Vol. LI. Part II. and Pages 898, 899. 
Expla- 
