of Edinburgh, Session 1885 - 86 . 
781 
affinity of the positive element of the salt for 0 on the heat of 
solution. The following illustrations will show the effects of the 
affinity of the negative element for H : — 
Compound. 
Heat of Com- 
bination. 
Difference. 
Heat of Solu- 
tion of 
Chlorides, &e. 
Difference. 
[Kj Cl] 
105610 
-4440 
[H,Cl,Aq] 
39315 
66295 
[K,P>r] 
95310 
-5080 
[H,Br,Aq] 
28380 
66930 
-635 
+ 640 
[K,Br] 
95310 
-5080 
[H,Br,Aq] 
28380 
66930 
[K,I] 
80130 
-5110 
[H,i, Aql 
13170 
66960 
-30 
+ 30 
Exactly similar results are obtained with all the soluble chlorides, 
bromides, and iodides for which data are available, with the excep- 
tion of AuC 1 3 and AuBr 3 ; the difference of heats of solution of 
these salts being too great in comparison with above. It is appa- 
rently proportional, however. 
It is pointed out in Muir and Wilson’s book that between the 
heats of formation of soluble chlorides, bromides, and iodides in 
water, there' is a constant difference, no matter what the positive 
element is. Thus we have — 
Salt. 
Heat of Formation. 
Salt. 
Heat of Formation. 
[H,Cl,Aq] 
39315 
[H,C1, Aq] 
39315 
[H ; Br,Aq] 
28380 
[H,I, Aq] 
13170 
Difference, 
10935 
Difference, 
26145 
[K,01, Aq] 
101170 
[K,C1, Aq] 
101170 
[K, Br,Aq] 
90230 
[K,I,Aq] 
75040 
10940 
26130 
