[ 144 ] 



negatively, unlcfs the contrary eledn'city can take place on other 

 bodies contiguous to it. Prop. 2. There is fomething on the fur- 

 face of bodies, which prevents the fudden incorporation of the two 

 eledricities, viz. of that pofleffed by the eledrified body with 

 the contrary eledricity poffefTed by the contiguous air, or other 

 furrounding bodies. Prop. 3. Suppofing that every particle of a 

 fluid has an attradion towards every particle of a folid ; if the 

 folid be left at liberty in a certain quantity of that fluid, it will be 

 attraded towards the common centre of attraction of all the par- 

 ticles of the fluid. To this laft propofition he has fubjoined the 

 two following corollaries: i.* the fame thing muft happen, when 

 the quantity of fluid is fmaller than the bulk of the body ; 2. if the 

 attradion of the particles of the fluid be exerted only towards the 

 furface of the folid, the efFed will be the fame when the body is 

 of a regular fhape ; but the difference will in any cafe be inconfi- 

 derable. 



With regard to the folution founded upon thefe principles it 

 muft be remarked, that it is not derived fimply from a confidera- 

 tion of the fuppofed nature of the eledric fluid ; but from a mixed 

 flatement of that nature and of properties afl!umed merely from 

 experiments as matters of fad. The firft and fecond propofitions 

 exprcfs tbofe properties, and, though the experiments to which 

 the former refers, may be explained by afcribing the phasnomena 

 to the repu'five nature of the fluid, yet the latter is afl"umed 



" without 



• Of this corollary Mr. Cavallo does not appear to make any diftinft application. 



