IN GASES : HYDROGEN, CARBONIC OXIDE, AND OXYGEN. 
G83 
simultaneously a reverse action took place between the hydrogen and carbonic acid 
resulting in the formation of steam and carbonic oxide. Finally an equilibrium was 
established between the action and reverse action when the amount of each per unit 
of time was equal to that of the other. 
In a paper by Mr. Harcourt and myself, communicated to the Royal Society in 
November, 1865 (Transactions, Yol. 156, p. 217), it is shown that the amount of action 
per unit of time between two substances is proportional to the quantity of each 
substance. In the course of a hitherto unpublished investigation on the reaction of 
hydrogen iodide and peroxide a case of equilibrium occurred in November, 1865, 
precisely analogous to the present case, and admitting of the same explanation. The 
two cases are represented by the following chemical equations 
fI 2 0 2 +2HI=2H 2 0+I 2 
2 n 2 o+1 2 =h 3 o 2 +2 hi 
h 2 o+co=h,+co 2 
h 2 +co 2 =h 2 o+co 
If in general A T , B 1? A 2 , B 2 are substances reacting according to the chemical 
equation 
A 1 + B : =A 2 +B 2 , 
A;3+B 2 = A 1 +B 1 , 
and if cq, a 2 , b 1} & 2 are the quantities of A 1} A 2 , B l9 B 2 respectively in an unit of 
volume, the amount of the first action per unit of time is acqZq, and the amount of the 
second action per unit of time is /3a. 2 b. 2 , so that when equilibrium is established 
a.a l b 1 =fia a b i . 
In the present case, if FLO, CO, H 2 , C0 2 represent the quantities per unit of 
volume of steam, carbonic oxide, hydrogen, and carbonic acid respectively, the ratio of 
HoO X CO to H 2 X C0 2 is a ratio independent of the quantities of substance taking 
part in the reaction, and depending only upon the conditions of temperature, pressure, 
&c. In the experiments which Mr. Dixon submitted to me this constant is 5, and on 
p. 660 the numbers calculated on this hypothesis are compared with those actually 
found. 
The calculation of the steam and carbonic acid ultimately remaining after the 
explosion of given quantities of hydrogen, carbonic oxide, and oxygen is effected in 
the following way:-— 
Let a, b, c be the original quantities of hydrogen (H 2 ), carbonic oxide (CO), and 
oxygen (0 3 ) respectively, and x the ultimate quantity of steam, then the ultimate 
4 s 2 
