156 
PROFESSOR KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
74. Crystallized Sulphate of Magnesia, Mg S0 4 +7 H 2 G. Air-dried crystals of Epsom 
salt. I have made two series of experiments with this salt. In one the temperature 
did not exceed 40°, and in the other did not attain 50°. In both cases the crystals 
remained transparent and unchanged. 
I. — Experiments with Naphtha A. Glass 3. Temperature of the Air 19°-8-19° -9. 
T. 
T'. 
t'. 
t. 
M. 
m. 
/• 
y- 
X. 
sp. H. 
O 
O 
0 
o 
grms. 
grms. 
grm. 
grm. 
38-5 
21 6 
21-29 
19-77 
26-96 
3-175 
1-845 
0-431 
0-453 
0-371 
39-3 
21-6 
21-32 
19-73 
26-945 
,, 
55 
55 
5J 
0-369 
38*7 
21-6 
21-34 
19-83 
26-98 
55 
55 
55 
0-357 
37-7 
21-6 
21-27 
19-85 
26-935 
„ 
1-835* 
55 
„ 
0-356 
Mean . . . O’ 363 
II. — Experiments with Naphtha A. Glass 1. Temperature of the Air 16°T. 
T. 
T'. 
t r . 
t. 
M. 
m. 
/• 
y- 
X. 
sp. H. 
o* 
o 
o 
0 
grms. 
grms. 
grm. 
grm. 
47-6 
18-3 
18-04 
15-42 
26-97 
2-775 
1-81 
0-431 
0-651 
0-353 
47*9 
18-4 
18-12 
15-43 
26-985 
55 
55 
55 
55 
0-371 
45-2 
18-3 
17-96 
15-53 
26-94 
„ 
55 
55 
55 
0-361 
43-9 
18-3 
17-96 
15-67 
26-975 
55 
1-795 
* 
55 
55 
0-356 
Mean . . . 0-360 
These determinations give as the mean of the two series 0 - 362 for the specific heat of 
crystallized sulphate of magnesia below 50°f . 
Crystallized Sulphate of Zinc, Zn S0 4 +7 H 2 0. Transparent crystals of white vitriol, 
dried in the air. In the determinations a heat but little over 50° could be employed; 
towards 50° the crystals undergo decomposition in the coal-tar naphtha J. 
Experiments with Naphtha A. Glass 1. Temperature of the Air 13°-4. 
T. T'. t'. t. M. m. /. y<. x. S p. H. 
ooo o grms. grms. grm- grm. 
28-7 14-6 14-33 12-93 26-945 3-55 1-655 0-431 0-651 0*369 
30-7 14-9 14-62 13-13 26-95 „ „ „ „ 0-332 
This series of experiments had to be interrupted here. I subsequently made another set. 
* After drying the stopper. 
f Above 50° the salt with 7 at. water of crystallization undergoes decomposition. A series of experiments 
in which the temperature exceeded 50° gave the following results. 
Experiments with Naphtha A. Glass 3. Temperature of the Air 20°-3-21°-l. 
T. 
T'. 
t'. 
t. 
M. 
m. 
f- 
y- 
X. 
sp. H. 
o 
51-5 
22-6. 
22:32 
1061 
grms. 
26-995 
grms. 
3-43 
grm. 
1-57 
0-431 
grm. 
0-453 
0-409 
51-4 
22-8 
22-52 
19-55 
26-93 
„ 
„ 
)} 
0-475 
51-0 
23-0 
22-71 
19-73 
26-945 
„ 
„ 
„ 
0-507 
500’ 
23-0 
22-71 
19-81 
26-93 
„ 
1-56* 
„ 
99 
0-515 
The results are as if more and more water in the free state had been eliminated.. After the experiments the 
crystals were swollen, and externally milk white, still containing a clear nucleus inside. 
% In the following series of experiments, in which a heat of towards 50° was employed, the crystals of white 
