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The permanence of either kind of electricity i'& 

 the clouds, or the length of time in which neither 

 can be difcovered, is uncertain > fometimes the fame 

 electricity has returned, and at other times has been 

 fucceeded by the contrary ; whilfr either generally 

 came on, and went off gradually. Rut changes were 

 often made, very fuddenly, by a flam of lightning, 

 efpecially if the thunder-ftorm happened to be in 

 the zenith. A branch of it, over-head, has fre- 

 quently occasioned flronger electricity than I could 

 difcover, when the greateft part of the iky had been 

 overcaft ; which, perhaps, might be accounted for, 

 from this coniideration, that one kind of electricity 

 acting alone, mud exert more powerful effe&s than 

 when counteracted by the other. 



I once obferved in a thunder-florm, during: which 

 I faw no lightning, that the balls, which hung 

 from the tin tube, repelled and attracted each other, 

 very rapidly, for the fpace of ten or twelve feconds j 

 at the fame time, Mr. Canton* s electrometer, which 

 I held at fuch a diflance from the tube, as to have its- 

 balls opened to the difrance of an inch, continued quiet 

 in that (fate, and were not affected ccnvulfively like 

 the others. Hence I imagined, that the fame kind 

 of electricity went off, and came on, without being 

 changed in contrarium; for when that circumftance 

 happened, they were very evidently affected in the 

 fame manner. And here I mud obferve, that 

 I have found it more eafy to difcover the kind of 

 electricity prefent in the tube, by approaching ex- 

 cited wax to the balls of an electrometer, which I 

 held at a proper diftance from the tube, than by ap- 

 plying it near the balls which hung from the tube $ 



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