NATURE OF SOLUTION. 609 
phenomenon appeared in an earlier set of experiments, and indeed the chlorine 
was in each case passed through the solution for about two hours before any 
determinations were made. An explanation of this and other maxima, occurring 
without formation of hydrate, will be suggested further on. 
Calcium, strontium, and barium form a series, the solubility of chlorine in 
solutions of their chlorides decreasing with increase of atomic weight. 
Magnesium Chloride.—With this solution no chlorine hydrate was obtained 
even at —7°°5, and a maximum of solubility appeared at about 2°. 
Mg(Cl, . 
t p Na,S,0, a 
—7°5 #69 11-2 10059 
—5'6 14:1 1:2664 
—4°7 16:2 14550 
—32 17-4 15627 
—08 17°7 15897 
+14 18:1 16256 
3°5 17°8 15987 
57 174 1:5627 
85 16:2 1:4550 
12'8 15°7 14101 
1917 13°8 12394 
26:1 11°9 1:0688 
31'3 10°6 0:9520 
37°3 8°7 07814 
1 cc. =0°010337 iodine. 
Ferric Chloride.—A neutral solution of this salt was obtained by dissolving 
pure iron wire in hydrochloric acid, keeping the iron in excess, estimating the 
iron and diluting to the required strength. The solution did not allow the 
formation of chlorine hydrate, but on the contrary decomposed it when previ- 
ously formed (Cf Calcium Chloride). As ferric chloride slowly sets free iodine 
from iodide of potassium, the usual method of estimating the dissolved chlorine 
was varied. The solution was poured into excess of Mohr’s salt, and the 
excess titrated with permanganate of potash. It was found extremely difficult 
to prevent loss of chlorine unless an enormously large excess of Mohr’s salt 
was used. The results are, however, sufficiently accurate to show that there is 
a maximum also in this case, although not very well defined. 
He Cl... 
i ay 
— 6:0 1:2748 
—54 1:3038 
—3°0 1:33.28 
