1911-12.] Absorption of Light by Inorganic Salts. No. VI. 57 
value of A for a nonaqueous alcoholic solution is 232, and that the alcoholic 
solutions I, II, and III contain ‘6 grm.-mol. of water per litre. The other solu- 
tions contain correspondingly more water than was stated on pp. 53 and 54. 
The proportion of cobalt chloride existing in the blue phase in any solu- 
A A 
tion is obviously given by 9 ^ 9 , and in the red phase by 1 — where 
A is the maximum value of the red band for that solution. 
I next attempted to apply the law of mass action. That this law is 
applicable is indicated by the fact that where the proportion of alcohol to 
Fig. 2. 
cobalt chloride is constant, as throughout each series, the amount of red 
phase increases with the amount of water, and where the proportion of 
water to cobalt chloride is approximately the same as in Id and 115 and in 
I Id and III6, the amount of blue phase increases with the amount of 
alcohol. It was assumed that the alcohol acted only as a diluent. This is 
open to question, as on bringing alcohol and water together there is a 
shrinkage in volume ; but this does not necessarily mean chemical combina- 
tion, and the assumption seems to be justified by the results. The change 
in the solution is obviously due to hydration, since in the blue phase there 
is no water at all. A question arises about the nature of the red phase. 
Some authorities are of opinion that it is the hexahydrate. But the absorp- 
tion spectrun^ of the hexahydrate crystal is entirely different from that 
of the aqueous solution. The former has two bands, the larger with a 
maximum about A = 550 jUL/m, and the smaller with a maximum about A =■ 
