246 Proceedings of Eoyal Society of Edinburgh . [sess. 
A first series of experiments with a constant quantity of magnesia, 
viz., 0'4 gram, and a constant volume of solution, viz., 25 c.c., 
resulted as follows, the numbers being in terms of decinormal 
iodine solution. 
Iodine taken. 
Iodine remaining. 
Iodine absorbed. 
27-0 
23*60 
3-40 
13-5 
10-85 
2-65 
675 
4-60 
2-15 
3*37 
1-85 
1-52 
Here, as in the case of aqueous solutions, the concentration of 
iodine in magnesia diminishes with the concentration of the 
chloroform solution, but less rapidly than the latter. The actual 
amount of iodine absorbed is much smaller than before, being in 
the first experiment 047 I 2 in lOMgO, compared with about 
3 0 I 2 in lOMgO from a corresponding aqueous solution. The 
hydroxide is thus much more capable of absorbing iodine than 
the ignited oxide. 
A set of experiments in which the ratio of magnesia to iodine 
was kept constant, the amount of chloroform alone being varied, 
was also made, with the following results : — 
Magnesia. 
Volume. 
Iodine taken. 
Iodine 
remaining. 
Concentration. 
Iodine 
absorbed. 
0-4 g. 
25 c.c. 
26-82 
24*56 
24*56 
2-26 
9 9 
50 „ 
9 9 
25-26 
12-63 
1-56 
9 9 
100 „ 
9 9 
25-70 
6-42 
1-12 
> 9 
o 
o 
9 9 
26*80 
335 
0-02 
Again the amount absorbed by the magnesia falls off as the 
concentration of the solution diminishes, the decrease being very 
marked and comparable with the decrease when the total volume 
remained constant and the amount of iodine was varied. The 
second set of experiments cannot he compared directly with the 
first, as it was necessary to reignite the magnesia. Other series 
with varying proportions were made, and although the numbers 
