1^6 >^;/ ESSAY conceding the Chap. 4. 



than Radiant manner, through the Rays and 

 Beams of Light, as before raention'd. Be 

 it which it will, I fay, the Sun is the Prime 

 Agent in this Aftair :, and the whole Procefs 

 is either Attradion, Pulfion, or Refpiration, 

 forwarded by its Virtual Power. 



That the Rarefaftion of Air by Heat, is a 



great help to Attradion, or Pulfion, is dif- 



coverable by Mr. Savory's Fire-Engine, where 



the Heat cannot be faid either to force or 



attract the Water ^ but by its Rarefying 



Quality lightens the Air that is in the Pipe 



to fuch a degree, that the Equilibrium is 



loft, and the Impulfe or PreJflTure of the Air 



Without, forces the Water to that great Height 



that is obferved in the Operation. 



In like manner a common Drinking- Glafs, 

 with a little fcrip of Paper burning and fuming 

 put into It, turn'd up immediately and put 

 upon a Plate of Water, will, as one wou'd 

 think, fuck it up into the Glafs 5 when in- 

 deed 'tis only the Outward PrefTure, and the 

 Inward Weaknefs of the Air to refift, ( being 

 purilied by Heat ) that is the truth of this 

 Experiment : For, on the contrary, if the 

 fame Drinking- Glafs were to be plung'd into 

 a Bafon of Water as high as the very Foot 

 of it, yet the Water that is in the Bafon fhall 

 not enter into the Glafs, 'till the Air, lofing 

 its own ftrength, or rather infinuating and 

 incorporating itfelf with the Water, lofes its 

 own force : So forcible is Air ^ which yet 

 the Unthinking part of Mankind fcarce ever 



fpend 



