27'8 Mr. M^noA^^h Experiments, &c. 



and was for fome time difpofed to believe the contrary of what 

 1 am now convinced to be the^^^truth. Indeed, if we reafon 

 a priori, I think we cannot luppofe a perfect vacuum to be a 

 perfect condudor Vv^ithout fuppofing an abfurdity: for if this 

 were the cale, eitlier our atmofphere muft have long ago been 

 deprived of all its eledlric fluid by being every where fur- 

 rounded by a boundlels condu6lor, or this fluid muft pervade 

 every part of infinite fpace, and confequently there can be no 

 fuch thing as a perfeft vacuum in the univerfe. If, on the 

 contrary, the truth of the preceding experiments be admitted, 

 it will follow, that the conducing power of our atmofphere in- 

 creafes only to a certain height, beyond which this power be- 

 gins to diminifh, till at laft it entirely vanlflies ; but in what 

 part of the upper regions of the air thefe limits are place i, I 

 will not prefume to determine. It would not, perhaps, have 

 been difficult -to have applied the refults of fome of thefe ex- 

 periments to the explanation of meteors, which are probably 

 owing to an accumulation of eledtricity. It is not, however, 

 my prefent deflgn to give loofe to my imagination. I am {qi\^ 

 iible, that by indulging it too freely, much harm is done to, 

 real knowledge ; and therefore, that one fa6t in philofophy well 

 afcertained is more to be valued than whole volumes of ipecu- 

 latlve hypothefes. 



dhatham-Place, Feb. 12, 1785. 





