1S4 ESSAYS AND OBSERVATIONS 



obferved amongft the diftant bodies of the 

 Iblar fyftem. 



When a heavy body lies upon a table, 

 and confequently adts upon it with its 

 whole weight, there muft be an equal re- 

 a<5lion from the power of cohefion of the 

 parts of the table, in order to fupport the 

 burden. In the fame manner, if the bot- 

 tom of any vefTel fuflains the weight of a 

 certain quantity of fand, it muft readt 

 with a force equal to that weight ; other* 

 ways it muft break or give way. The 

 power of cohelion may indeed greatly 

 exceed the particular weight which it hap- 

 pens to countera(5l at any time: And the 

 fame table, at different times, may fup- 

 port very difterent degrees of weight. But 

 ftill it is true, that the force exerted by 

 this power upon the body can neither be 

 greater nor lefs than its weight, fince the 

 readlion barely fupports the body without 

 beginning motion in it. If this needs 

 anv illuftration, we may fuppofe a mian 

 to have a weight hanging at his hand, 

 while at the fame time he prelles that hand 

 upwards againft any fixed body, the force 



■with 



