46 ESSAYS AND OBSERVATIONS 



fequence in fluids, but in folids equally. 

 Here then is a fair dilemma. We mud 

 either acknowledge a prefTure undequaque 

 in fand, powder, and indeed in all loofe 

 bodies, as well as in fluids; or confine 

 this law of the equality of acflion and re- 

 aiflion to fluids. Can we remain a 

 moment in doubt betwixt thefe op- 

 pofites? We are certain that a prefTure 

 undequaque \s not a property of folids. The 

 equality of adlion and readlion is but an 

 aflertion without evidence. What re- 

 mains then, but that we adhere to the 

 former, and rejedl the latter, except as to 

 fluids. And thus our author luckily, 

 though without intention, has furniflied 

 a very convincing argument againft the 

 univerfality of this fuppofed law of ac^- 

 tion and readlion. If an undequaque 

 preflure is an eflecl of tliis law, it follows 

 clearly, that this law takes not place in 

 folids, at leaft: not univerfally, as in' 

 fluids. 



Op 



