160 
PROFESSOR KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
II. — Experiments with Water. Glass 1. Temperature of the Air 17 0, 5-17°‘4. 
T. 
T'. 
t'. 
t. 
M. 
m. 
/• 
y- 
X. 
sp. H. 
O 
O 
0 
o 
grms. 
grms. 
grm. 
grm. 
50-2 
19-8 
19-54 
15-54 
26-955 
3-525 
1-995 
1-000 
0-651 
0-256 
50-1 
19-6 
19-33 
15-31 
26-94 
55 
55 
55 
jj 
0-257 
50-5 
19-7 
19-36 
15-24 
26-96 
V 
55 
55 
„ 
0-272 
49-2 
19-7 
19-43 
15-52 
26-97 
„ 
55 
55 
w 
0-263 
47-8 
19-7 
19-36 
15-62 
26-99 
5,5, 
1-965* 
55 
„ 
0-277 
Mean . . . 0-265 
I should not have hesitated to take the number 0 - 27, the mean of the averages of both 
these series of determinations, as the normal specific heat of sesquichloride of carbon, and 
to consider it as sufficiently below the melting-point (according to Faraday this is at 
160°), if the connexion between the specific heat of solid bodies and their composition, 
discussed in § 96 et seq., had not been known to me; but the specific heat of sesqui- 
chloride of carbon calculated therefrom is 0-177. This deviates from the number found 
in a manner which at first I could not understand. The idea that the specimen was im- 
pure was inadmissible f. To try whether the porcelain-like mass of sesquichloride which 
solidified on fusion had an essentially different specific heat from that not fused, I re- 
crystallized the substance from ether, washed the crystals (which showed very distinctly 
the characteristic form of the body as described by Brooke and Laurent) with a little 
ether, and dried them at 100°. Dried at this temperature, without being melted, they 
were white, like porcelain, and gave now the following results. 
III.— Experiments with Water. Glass 3. Temperature of the Air 18°*4-18°-7. 
T. 
T'. 
t'. 
t. 
M. 
m. 
/ 
y • 
X. 
sp. H. 
49-2 
20-6 
20-34 
16-53 
grms. 
26-935 
grms. 
3-835 
grms. 
2-06 
1-000 
grm. 
0-453 
0-280 
49-2 
20-7 
20-42 
16-62 
26-94 
55 
55 
55 
55 
0-281 
49-0 
20*8 
20-53 
16-81 
26-95 
2-05* 
55 
5 5- 
0-274 
Mean . . . 0-275 
That is essentially the same specific heat as my earlier experiments gave. If now it 
was improbable that the specific heat of sesquichloride of carbon did not differ much 
from 0 - 27, I might, on the other hand, also consider it improbable that this compound 
would make an exception to the relation which I had found between specific heat 
and composition — a relation which holds good in hundreds of cases of solid bodies. 
Sesquichloride of carbon would be the only exception to the validity of this relation ; 
but this single exception would be sufficient to disprove its universal applicability, 
* After drying tlie stopper. 
t In the specimen I investigated, Mr. Dehx found 90T9 per cent, chlorine ; the quantity calculated from 
the formula C 2 Cl a is 89-88 per cent. 
