PROFESSOR KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
97 
25. I first attempted to test my method by some experiments in which water or 
mercury was placed in the calorimeter. For the specific heats of these liquids the fol- 
lowing numbers were obtained, calculated by the formula 
tt_ M (t' — t)—X (T — T') 
P* /(T-T') 
in which the signification of f is manifest from what follows, that of the other letters 
from what has been given before. 
In the experiments in which a readily vaporizable liquid was contained in the glass, 
such as water, or coal-tar naphtha, a sensible formation of vapour took place, although 
the temperature did not exceed 50°. If the glass containing the liquid was heated 
in the mercury-bath (compare fig. 7), vapour was formed in the empty space below 
the cork which served as stopper; if the glass was then brought into the water of 
the calorimeter, this vapour condensed and settled partially on the stopper. The 
stopper did not act materially on the water of the calorimeter (see fig. 5). The 
quantity of liquid in the glass which acted directly on the water of the calorimeter, 
decreased somewhat in each experiment ; but this decrease is very inconsiderable. In the 
following experiments y denotes first the weight of the liquid in the glass at the com- 
mencement of the experiment, and at last its weight at the end of the experiments, that 
* is, after subtracting the liquid which had vaporized and condensed on the stopper. 
After the end of the experiment the stopper was dried to remove the liquid, and by 
another weighing of the glass, together with its contents and stopper, the weight of the 
liquid still contained in the glass was obtained. The decrease of weight of the liquid 
in the glass was always found to be inconsiderable, and might without any harm have 
been neglected ; for the last experiment of a series I have always taken the diminished 
weight of the liquid into account, but for those between the first and the last I have 
neglected the diminution of the weight of the liquid in the glass. What I have here 
said explains a remark of frequent subsequent use, “ after drying the stopper.” In re- 
ference to the influence of the formation of vapour on the accuracy of the results obtained 
for the specific heat of the individual substances, compare §38. 
Two series of experiments in which water was contained in the glass, gave the fol- 
lowing results for the specific heat of this liquid : — 
Experiments with Glass 1. Temperature of the Air 19 o, 0. 
T 
T'. 
t\ 
45*2 
20-9 
20-62 
46-6 
21-2 
20-92 
47-4 
21-3 
20-96 
t. M. 
o grms. 
16- 83 26-945 
17- 03 26-935 
17-03 26-965 
* After drying the stopper. 
/• 
sp. H. 
grms. 
grin. 
3-43 
0-651 
1-035 
1-013 
3-42* 
0-997 
P 
q 
