Miftellanea Curiofa. 87 



dies, which aliimulating into the Form of Air, 

 are kept fufpended therein, as Saks diffolv'd 

 in Liquors* or [Metals in corroding Men fir un \ 

 which Bodies being all of them very much hea- 

 vier than Air, their Particles by their Admix- 

 ture mult needs encreafe the weight of that Air 

 they lie incorporated withal, after the fame man- 

 ner as melted Salts do augment the fpecifick 

 Gravity of Water. The other Confederation 

 is, that the RarifacHon and Condenfetion of 

 the Air is not precifely according to the pro- 

 portion here laid down ; for the Experiment ve- 

 ry nearly agrees thereto, as may be feen in the 

 58th Chapter of Mr. iJoclCs Micrography 9 yet 

 are the Condenfations not poffible beyond cer- 

 tain degrees : For being compreffed into an . 

 Sooth part of the Space ic takes up here, its 

 confidence would be equally denfe with that of 

 Water ' y which yields not to any force whatfb- 

 ever, as hath been found by feveral Experiments 

 tried here, and at Florence, * by the AcddemU 

 del Cimento. Nor can the R.arifac~lion proceed 

 in infinitum j for fuppofing the Spring where- 

 by it dilates it felf, occahon"d by what Tex- 

 ture of Parts you pleafe, yet muft there be a 

 determinate Magnitude of the natural State of 

 each Particle, as we fee it is in Wool, and the 

 like, whofe Bodies being compreflable into a very 

 fmall Space, have yet a determinate bulk which 

 they cannot exceed, when free'd from all manner 

 ofPreflure. 



Thcfe Objections being true, do difturb the 

 Geometrical Accuracy of thcfe ConcluGons, 

 drawn from the fpecifick Gravity of the Air 

 obferv'd at any time y but the Method here 

 fhewn will compute by a like Calculation, the 

 heights of the Quick-filver, and the Rari&&ions 

 G 4 of 



