SOLUBILITY OF SALTS IN WATER AT HIGH TEMPERATURES. 
31 
Observer. 
Temperature. 
Poggiale (Ann. Chim. 
O 
0 
Phys. [3], viii., 469) 
20 
35 
70 
100, &c. 
T. and S. 
140 
Exp. 1. - 080 
„ 2. -076 
„ 3. -080 
160-165 
„ 1. -056 
„ 2. -056 
175-185 
„ 1. -024 
178-183 
240 
250 
„ 2. -030 
Parts of CaS0 4 in 100 of water. 
•205 
•241 
•254 
■ 0/1,4 
•217, &c. 
Mean - 078 
„ -056 
„ -027 
•018 
•018 
(See Plate 2.) 
This curve is interesting as having considerable resemblance to that of sodium 
sulphate. Experiments at 250° were repeated, but without any indications that the 
solubility was about to increase, and this was the highest temperature at which we 
have been able to work. Calcium sulphate is much less fusible than sodium sulphate, 
and we could not therefore expect that a change would be observable in the direction 
of the curve, unless the temperature were carried much higher than we found it 
possible to go. 
Potassium sulphate.—Melting-point ?. 
Temperature. 
Parts of KoS0 4 in 
100 parts of water. 
Gat Lussac. 
T. and S. 
O 
0 
8-3 
127 
10-5 
16 
976 
20 
10-30 
28 
12-59 
36 
13-28 
39 
14-21 
49 
16-9 
59 
17-39 
63-9 
19-2 
98 
23-91 
101-5 
26 
120 
26-5 
143 
28-8 
170 
32-9 
(See Plate 1.) 
These results give a curve which is nearly a straight line. Our figures are 
uniformly somewhat lower than those of Gay Lussac. Curves constructed with the 
