Chemical Combination of Gases. 

 dm __ 2n r _^ 2m g _jmp 



dt ti t 3 T X T 2 



249 



dn 

 dt 





^ 2j , r _2p 2 _mp 



dt 



7-3 7-2 



> 



(7) 



rfy _ p 2 (7 



5? 



To £ a 



Let us first consider the case when things have got into a 



, , . , . ., . dm dn dp da dr „ 



steady state; in this case -y ^, £, g, g are all zero, 



and the above equations may be written: — 



mp r 



(8) 



These, with the equations 



m+2n+r=M } 



p + 2q + r=~N, 

 will be sufficient to determine the five quantities ?n, n,p, q, r. 

 We shall get much simpler equations if we suppose, as is 

 nearly always the case, that the number of free atoms of 

 hydrogen or chlorine is very small compared with the number 

 of hydrogen or chlorine molecules respectively. Making this 

 assumption, we may write 



» = i(M-r), 



q = i(N-r). . 

 Multiplying the first two equations of (8) we get 



ng 



m 2 p 2 



T lT"3 hh ' 



Using the third equation of (8) we get 



t 2 / 2 



Phil Mag. S. 5. Vol 18. No. 113. Oct. 1884, 8 



