PROFESSOR KOPP ON THE SPECIFIC HEAT OF SOLID BODIES. 
95 
a second, B, showed that of the calorimeter water. If the glass filled with the warmer 
water is immersed in the cold water, the following circumstances are observed*. A sinks 
very rapidly, while B rises more slowly ; if B shows the maximum temperature for the 
water of the calorimeter (this temperature being called ^'), A gives a higher temperature 
(T) for the contents of the glass. B then slowly sinks and A follows it, while the difference 
between if and T' always becomes smaller. In the two following series of experiments I 
have endeavoured to determine by how much, under certain conditions, the temperature 
T' of the water in the glass exceeds the maximum temperature if of the water in the 
calorimeter when this maximum temperature as such is observed. I obtained the 
following results: the temperature of the air in the experiments was 13°-2-13°-5. 
Experiments with Glass 1. Experiments with Glass 2. 
T'. 
t\ 
Difference. 
T'. 
?. 
Difference. 
15-51 
15-13 
d-38 
15-71 
15-50 
0-21 
14-96 
14-72 
0-24 
15-96 
15-65 
0-31 
16-11 
15-94 
0-17 
15-16 
14-91 
0-25 
15-56 
15-36 
0-20 
14-76 
14-47 
0-29 
14-24 
14-05 
0-19 
14-66 
14-33 
0-33 
15-96 
15-64 
0-32 
15-56 
15-24 
0-32 
A closer agreement in 
the numbers 
expressing the difference between T' and if is 
difficult to attain, 
since a 
certain time 
is necessary to 
observe the 
occurrence of the 
maximum temperature, and during the time in which the thermometer B remains con- 
stant, the thermometer A still sinks ; according to the moment at which the maximum 
temperature is considered to be established, this difference may be obtained different, 
and the smaller the later the observation is made. Moreover the magnitude of this 
difference between T' and if depends on the difference between t and the temperature 
of the air. I have always endeavoured to work under the same circumstances, and 
especially to arrange the experiments so that the maximum temperature of the water 
in the calorimeter did not exceed by more than 2° the temperature of the air f. For 
these experiments and the apparatus which I used, I assumed, on the basis of the 
preceding experiments, that if the water of the calorimeter had assumed its maximum 
temperature t', the contents of the glass were 0 o- 3 higher ; that is, I put throughout T', 
the temperature to which the contents of the glass immersed in the calorimeter had 
fallen, =tf'4-0°-3. 
24. It is a matter of course that, in introducing this correction for obtaining the tem- 
* In these experiments, in order to ensure uniformity in the temperature of the water, the stirrer was kept 
in continual motion, and the same process followed as in ascertaining the specific heat. 
t A preliminary experiment shows how cool the water in the calorimeter ought to he. Water which is 
somewhat cooler than the surrounding air, may he kept in stock for such experiments by placing it in a cylin- 
drical flask covered externally with filtering paper, and standing in a dish of water, so that the paper is always 
moist. To warm the water in the calorimeter, it was merely necessary, with apparatus of the dimensions I 
used, to lay the hand on it for a short time. 
MDCCCLXV. P 
