126 Br. Perchal on the different ^antUies 



at York, at the time when there were fmall 

 drizzling rains, with thick mifts, in the ftreets 

 below.* 



The Memoir, of which I have here given a 

 brief view, was diftributed amongft my literary 

 correfpondents, and procured me many curious 

 and interefting obfervations on the fubjedl. And, 

 I truft, my friend Dr. Franklin will forgive the 

 liberty 1 take, in communicating, to the fociety, 

 the following letter, with which I was honoured 

 by him, on this occafion. The opinions and 

 conjectures of fo eminent a philofopher may, 

 almoft, be deemed common property; and on 

 the point in queflion, they are of peculiar value 

 and ayihority. 



Extract of a Letter from Benjamin Franklin, 

 LL. D. &c. /o Dr. Percival. 



** ON my return to London I found your 

 favour, of the fixteenth of May ( 177 i). I wi(h 

 I could, as you defire, give you a better expla- 

 nation of the phjenomenon in queftion, fince 

 you feem not quite fatisfied with your own ; but 

 I think we want more and a greater variety of 

 experiments in diiferent circumftances, to enable 

 us to form a thoroughly fatisfaftory hypothefis. 



• Hunter's Georgical EfTays, p. 112. 



Not 



