22 On the Absorption of Gases 



or repfiilsive power amongbt their own particlesj just the same 

 in the water as out of it, the intervening water having no 

 other influence in this respect than a mere vacuum. 



3. Each gas is retained in water by the pressure of gas of its 

 own kind incumbent on its surface abstractedly considered, 

 no other gas with which it may be mixed having any per- 

 manent influence in this respect. 



4. When water has absorbed its bulk of carbonic acid 

 gas, &C. the gas does not press on the water at all, but 

 presses on the containing vessel just as if no water were in. 

 Wlien water has absorbed its proper quantity of oxygenous 

 gas, &c. that is, -^ of its bulk, the exterior gas presses on 

 the surface of the water with -irf of its force, and on the in- 

 ternal gas with -j-y of its force, which force presses upon the 

 containing vessel and not on the water. With azotic and 

 hvdrogenous gas the proportions are |-|- and -^-V respectively. 

 When water contains no gas, its surface must support the 

 ■whole pressure of any gas admitted to it, till the gas has, in 

 part, forced its way into the water. 



5. A particle of gas pressing on the surface of water is 

 analogous to a single shot pressing xipon the summit of a 

 square pile of them. As the shot distributes its pressure 

 equally amongst all the individuals forming the lowest stra- 

 tum of the pile, so the particle of gas distributes its pressure 

 equally an.pagst every successive horizontal stratum of par- 

 ticles of water downwards till it reaches the sphere of influ- 

 ence of another particle of gas. For instance, let any gas 

 press with a given force on the surface of water, and let the 

 distance of the particles of gas from each other be to those 

 of water as 10 to 1; then each particle of gas must divide 

 its force equally amongst 100 particles of water, as follows: — 

 It exerts its immediate force upon 4 particles of w^atcr j those 

 4 press upon 9, the 9 upon 16, and so on according to the 

 order of square numbers, till 100 particles of water have the 

 force distributed amongst them ; and in the same stratum 

 each square of 100^ having its incumbent particle of gas, the 

 water below thi.- siralum is uniformly pressed by the gas, 

 and consequently has not its equilibrium disturbed by that 

 pressure. 



When 



