50 
Proceedings of Boy al Society of Edinburgh, [jan. 1 7, 
Again, take SrS0 4 , and proceeding exactly in the same way, we 
have the following result: — 
[Sr, O] = 128440 [Sr, S, O 4 ] = 330900 
[S, O 3 ] =103240 
231680 
Difference 99220 = [Sr, S] 99200 
330900 330900 
[SrO, Aq] = 29340 
[SO 3 , Aq] = 39153 
Neutralisation = 30710 
99203 
Now, both these salts are insoluble in water for the same reason, 
viz., that the full affinity of the S for the metal is exercised, and 
nothing is left for the H 2 or O of the water. 
Let us take next CaS0 4 , and we shall find some still more 
remarkable results. In building this compound up 318370 units of 
heat are evolved. Tabulated in the same way as in the other cases 
we have — 
[Ca, 0] = 130930 [Ca, S, O 4 ] 318370 
[S, O 3 ] =103240 
234170 
Difference 84200 
318370 318370 
Now in this case the difference 84200 is not equal to the heat of 
[Ca, S], which is 92000. The S therefore is not held with the 
full strength of its affinity for Ca. There are 7800 units to spare. 
What becomes of them ] Consider the following : — 
[CaO, Aq] = 18330 
[SO 3 , Aq] =39153 
Neutralisation = 31440 
88623 
