206 PROPERTIES OF AIR 



dered a change from better to worse. Without 

 dwelling upon this particular point, I shall 

 proceed to show, that the particles of which 

 liquid water is composed, in common with 

 those of liquids in general, with relation to each 

 other, subsist in a state of equilibrium, pro- 

 vided those particles are of equal density. 

 The pressure upon the upper part is the same 

 as the pressure on the under one, as well as 

 from side to side. 



If in a column of water, or any other liquid, 

 the particle 2 presses upwards upon the par- 

 ticle 1, as much as the particle 1 presses upon 

 the particle 2 ; and the particle 2 presses upon 

 the particle 3, as much as the particle 3 presses 

 upon the particle 2 ; and so on to an indefinite 

 series : then must it follow, that all the united 

 particles by pressing, as much as they are 

 pressed ; and resisting, as much as they are 

 resisted, subsist, with respect to each other, 

 in a state of perfect equilibrium. If the pres- 

 sure is equal in the particles of which a column 

 of water is composed, then must it follow, that 

 the pressure of the whole column must be 

 equal also. If it were otherwise, if the pres- 

 sure at the bottom, was the sum of the parti- 

 cles altogether, in a regular and increasing 

 series, the whole would be different from the 

 parts. The pressure of the fluid would, in 

 that case, be less upwards and sideways, than 



