ai6 ESSAYS AND OBSERVATIONS 



ance for feveral days before this llorm ; 

 and, for feme nights after it, the ftre.ime- 

 ry vapour appeared equally difFuled, 

 muddy, inert, and languid, and not -vi- 

 brating any variety of colours j as if the 

 more volatile parts had been confumed. 

 It is highly probable that lightning and 

 the aurora borealis are of the lame mate- 

 rials. In hot countries dreamers are not 

 feen, or but rarely ; becaufe they are 

 kindled into thunder and flaflies of light- 

 ning: In cold countries flrealners abound, 

 and it feldom thunders. The ftrcamers 

 have ferved to predial thunder to follow 

 next day, in fummer j and they have 

 been alfo feen to break out into flaflies 

 pf lightning. Thunder difturbs the mo- 

 tion of the magnetic needle j and it has 

 been lately found in Sweden, that ftream* 

 ers do the fame. Thus thunder, electri- 

 city, magnetifm, and the aurora borealis^ 

 appear all wonderfully related ; and ma- 

 ny things remain undifcovered in this 

 vaft field> which is but jufl newly open- 

 ed. 



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