154 
Proceedings of the Royal Society of Edinburgh. [Sess. 
But the effect of adding water is quite different, as may be seen from 
the following table and curve. The concentration of the cobalt chloride 
in gm.-mols. per litre is denoted by c v and that of the water in the same 
units by c 2 . The increase of c 1 in the table is due to loss of acetone 
by evaporation. 
Effect of adding Water to a Solution of Anhydrous 
Cobalt Chloride in Acetone. 
Cl. 
A . 
•0508 
•00 
253 
•0508 
•63 
257 
•0523 
1-08 
257 
•0508 
1-68 
252 
•0508 
2*51 
240 
•0496 
4-20 
210 
•0472 
6-46 
77 
It is probable from the shape of the curve that the anhydrous cobalt 
chloride combines with the acetone. We did not expect this result. It 
did not seem worth while to attempt to apply the mathematics of mass 
action to our data. 
Finally, the case of the cobalt and nickel iodides was studied afresh. 
It will be remembered that according to the fourth article these salts 
gave an enormous absorption in the ultra-violet similar to that of an 
aqueous solution of iodine, A for nickel iodide agreeing roughly with its 
