112 
PEOFESSOE KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
I. Experiments with Naphtha A. Glass 3. Temperature of the Air 19 o -0-18°-7. 
T. 
T'. 
t'. 
t. 
M. 
m. 
/• 
y ■ ■ 
X, 
sp.H. 
O 
grins. 
grms. 
grms. 
grm. 
52-5 
20-8 
20-53 
18-21 
26-955 
2-51 
2-445 
0-431 
0-453 
0-186 
52-9 
21-1 
20-84 
18-54 
26-98 
55 
2-565* 
55 
55 
0-156 
51-4 
20-9 
2064 
18-43 
26-94 
„ 
55 
,, 
„ 
0-157 
52-0 
20-9 
20-60 
18-33 
26-99 
55 
2-545f 
„ 
55 
0-168 
Mean 
0-167 
.—Experiments with 
Naphtha 
A. Glass 1. 
Temperature of the Air 
19°-9-20°-0. 
T. 
T'. 
t'. 
t. 
M. 
ra. 
/• 
y- 
oc. 
sp. H. 
o 
O 
0 
o 
grms. 
grms. 
grms. 
grm. 
52-1 
21-9 
21-57 
19-32 
26-94 
2-48 
2-205 
0-431 
0-651 
0-164 
51-7 
22-0 
21-66 
19-45 
26-97 
55 
55 
55 
55 
0-163 
51-5 
22-0 
21-73 
19-54 
26-98 
55 
55 
„ 
0-162 
51-5 
22-0 
21-66 
19‘46 
26-945 
55 
2-19f 
55 
55 
0*167 
Mean . 
0T64 
The average of the means of both these series of experiments, 0T67 and 0T64, gives 
0T66 as the specific heat of iron graphite between 22° and 52°. 
The results previously known in reference to the specific heat of carbon, differ greatly 
for its different conditions, as also do the results obtained by different inquirers and 
by different methods for the same condition. But even leaving out of consideration the 
numbers obtained by De la Rive and Marcet by the method of cooling, there are still 
considerable differences between Regnault’s results, obtained by the method of mixture, 
and my own. Regnault found for animal charcoal 0-261, for wood-charcoal 0-241, for 
gas-carbon 0-209, for natural graphite 0-202, for iron graphite 0*197, for diamond 0-1469 ; 
his experiments gave greater numbers for the same substance than my own. I think that 
exactly for a substance like carbon in its less dense modifications, my method promises 
more accurate results than that of Regnault. Even in mine, the substance, after being 
strongly heated before the experiment, might absorb gases or aqueous vapour, which 
would make the specific heat too great. But in Regnault’s method this source of error 
might also operate, and more especially also the source of error due to the disengage- 
ment of heat when porous substances are moistened by water. These sources of error, 
which affect the determination of the specific heat of the various modifications of carbon 
and make it too high, have the more influence the looser and the more porous the sub- 
stance investigated. I believe that the only certain determination of the specific heat 
of carbon is that of diamond, and all other determinations are too high, owing to various 
circumstances, and in Regnault’s experiments with wood and animal charcoal, &c., 
owing to the heat disengaged when these substances are moistened by water. 
* After some more naphtha had been added. 
t After drying the stopper. 
