Chemical Combination of Gases. 261 



— = the time an oxygen atom remains free from 

 71 another oxygen atom. 



— = the time an oxygen atom remains free from a 



hydrogen molecule. 



To 



~ = the time an oxygen atom remains free from a 

 carbonic oxide molecule. 



M = the total number of hydrogen molecules, whether 

 free or in the water molecule. 



N = the total number of oxygen atoms, whether free 

 or in oxygen molecules, or in water, or carbonic 

 acid molecules, but not counting the oxygen 

 atoms in the carbonic oxide molecule. 



P = the total number of carbonic oxide molecules, 

 whether free or in the carbonic acid molecule. 



Then, by the same reasoning as before, we get the follow- 

 ing equations : — 



ra + s = M 



"" 



n + 2p + s + u = N 





r -f u = P 





dp __n 2 

 dt t x 





ds_nm 

 dt t 2 



s 



du _ nr 



u 



dt t 3 



h . 



(26) 



when things are in equilibrium ^, ^, ^ are a U zero . 



so that 



ri 2 _ p 



*1 



t. 



nm 



s 



T 2 ~ 



V 



nr _ 



T 3 



u 



V 



