1174 PROFESSOR M. BELLATI AND DR. R. ROMANESE ON THE SPECIFIC 
and between 13° C. and 148° C. 0'0686. The increase for temperature is therefore 
very little. 
PbI 2 .AgI. 
From 0° to 118° C., expansion. 
„ 118° „ 124° C., neither expansion nor contraction. 
„ 124° ,, 139° C., contraction, more rapid between 130° C. and 133° C. 
,, 139° „ 144° C., neither expansion nor contraction. 
„ 144° „ fusion, expansion. 
Our determinations gave the following results :— 
PbI a .AgI. 
T. 
Q. 
Difference. 
No. 
t. 
Observed. 
Calculated. 
r. 
42 
°C. 
12-65 
°C. 
65-82 
2-566 
2-558 
+0-008 
11*7 
43 
10-75 
62-56 
2-484 
2-491 
-0-007 
9-9 
44 
11-93 
113-0 
4*909 
4-904 
+ 0-005 
10-2 
45 
13-45 
112-9 
4-815 
4-823 
-0-008 
11-8 
46 
13-75 
171-1 
10-531 
10*529 
+ 0-002 
10-2 
47 
15-66 
171-4 
10-455 
10-456 
-0-001 
12-2 
48 
15-09 
242-4 
14-52 
14-51 
+0-01 
10-5 
49 
13-90 
242-0 
14*52 
14-54 
-0-02 
9-3 
c=0 - 047458+0'00000839 (T + 0 
c 1 =0 - 0567 
X=2‘556. 
The following table recapitulates our results. 0 1 and 0 a are the temperatures at 
which the structure-change commences and ends according to Mr. IIodwell’s 
experiments. 
Composition 
of the substance. 
Percentage 
of Agl. 
% 
c. 
Ci. 
Agl 
CtioX,.12AgT 
Cn 2 I 3 .4Ag-I 
Ctic,I 0 .3AgI 
Cu 2 I 3 .2AgI 
Cu 3 I 3 .AgI 
Pblg.Agl 
100 
88-1 
71-2 
65-0 
55-3 
88-2 
33-8 
°C. 
142 
95 
180 
194 
221 
256 
118 
°c. 
156-5 
228 
282 
280 
298 
324 
144 
0-054389+0-0000372 (T +£) 
0-05882 (from 16° to 89°) 
0-056526+0-0000410 (T+0 
0-059624+0-0000280 (T + f) 
0-061035 + 0-0000295 (T +t) 
0-063099+0-0000260 (T + i) 
0-047458+0-00000839 (T+t) 
0-0577 
0-0580 
0-0702 
0-0726 
0-0567 
6- 25 
8-31 
7- 95 
7-74 
7- 88 
8- 67 
2-556 
From these data we may deduce the following conclusions. 
V 
I. The specific heat of the bodies we experimented on, below the point at which a 
change of structure commences, increases with the temperature. 
