304 Mijcellanea Curidfa. 



miftaken the Caufe for the Effect: ; it being 

 from undoubted Principles plain, that the At* 

 mofphere has no other Preffure but what it de- 

 rives from its Gravity j and that the . Weight of 

 the upper Parts of the Air, prefling on the low- 

 er Parts thereof, do fo far bend the Springs of 

 that Elaftick. Body, as to give it a Force equal 

 to the Weight that comprefs'd it, having of k 

 felf no force at all: And fuppofing it had, it 

 will be very hard to explain the Modus^ how 

 that Preffure fhould occafion the Defcent of a 

 Body circumlcribed by it, and preffed equally 

 above and below, without fbme other Force to 

 draw, or thruft it downwards. But to demon- 

 ftrate the contrary of this Opinion, an Experi- 

 ment was long fince (hewn before the Royal So- 

 ciety, whereby it appeared, that the Atmofphere 

 was (b far from being the Caule of Gravity, that 

 the Effects thereof were much more vigorous, 

 where the Preffure of the Atmofphore was taken 

 off ; for a long Glafs-Receiver having a light 

 Down-feather included, being evacuated of Air, 

 the Feather, which in the Air would hardly fink, 

 did in vacuo defcend with nearly the fame Velocity , 

 as if it had been a Stone. 



Some think to illuftrate this Defcent of Hea- 

 vy Bodies, by comparing it with the Vertue 

 of the Loadftone j but fating afidc the diffe- 

 rence there is in the manner of their Attracti- 

 ons, the Loadflone drawing only in and about 

 its Poles, and the Earth near equally in all 

 Parts of its Surface, this Comparifon avails 

 no more than to explain ignotum per aaut 

 ignotum. 



