HEAT AND HEAT OF TRANSFORMATION OF IODIDE OF SILVER. 1173 
Cu 2 I 2 .2AgI. 
From 0° to 221° 0., expansion. 
„ 221° „ 233° C., neither expansion nor contraction. 
„ 233° „ 298° 0., contraction. 
„ 298° „ 496° 0,, expansion. 
We obtained :— 
CugIg.2AgI. 
T. 
Q. 
Difference. 
No. 
t. 
Observed. 
Calculated. 
T. 
31 
°C. 
11-70 
°0. 
63-86 
3-299 
3-300 
-0-001 
°c. 
10-6 
32 
13-10 
64-06 
3-227 
3-226 
+ 0-001 
12-0 
33 
13-36 
209-4 
13-23 
13-26 
-0-03 
8-7 
34 
15-12 
209-3 
1317 
13-14 
+ 0-03 
10-5 
35 
20-85 
305-7 
27-99 
28-01 
-0-02 
11-3 
36 
18-24 
306-9 
i 
28-29 
28-27 
+ 0-02 
8-5 
c=0-061035+0-0000295 (T+£) * 
X=7*88. 
Cu 2 I 2 .AgI. 
From 0° to 256° 0., expansion. 
„ 256° „ 284° 0., neither expansion nor contraction. 
„ . 284° ,, 309° 0., contraction. 
„ 309° „ 324° 0., neither expansion nor contraction 
„ 324° „ 514° 0., expansion. 
Our results are as follows :— 
Cu 3 I 3 .AgI. 
No. 
t. 
T. 
Q. 
Difference. 
Observed. 
Calculated. 
r. 
37 
°C. 
11-66 
°C. 
63-59 
3-378 
3-378 
10-4 
88 
15-05 
231-1 
15-05 
15*02 
+ 0-03 
9-2 
39 
15-46 
229-2 
14-81 
14-85 
-0-04 
9-7 
40 
20-19 
333-0 
31-29 
31-28 
+ 0-01 
8-1 
41 
22-26 
332-7 
31-11 
31-12 
-o-oi 
10-3 
c=0-063099+0-0000260(T+ 1) 
\=8-67. 
Some experiments were also made with Ou 3 I 3 , but this substance, when heated, emits 
iodine vapour, and is therefore slowly decomposed. Its surface was covered by some 
oxide. The mean specific heat between 13° C. and 65° C. would be found 0*0684, 
