Experiments upon Heat. 
65 
The bulb of the thermometer surrounded by 
0 
176 grains of fine 
1 7 6 grains of fine 
1 p tj grains of 
307 grains of 
powder of char- 
powder of char- 
lampblack. 
pure dry wood 
QJ 
coal. 
coal. 
ashes. 
Exp. No. 24. 
Exp. No. 25. 
Exp. No. 26. 
Exp. No. 27. 
0 0 
O O 
79" 
91" 
124" 
96" 
5°° 
95 
91 
ll8 
92 
40° 
100 
10 9 
134 
107 
3°° 
1 39 
133 
164 
I36 
20° 
196 
i9 2 
* 237 
185 
io° 
33 1 
321 
394 
311 
Total times. 
940 
937 
1171 
927 
The experiment, N° 25, was simply a repetition of that 
numbered 24, and was made immediately after it; but, in 
moving the thermometer about in the former experiment, the 
powder of charcoal which filled the globe was shaken a little 
together, and to this circumstance I attribute the difference in 
the results of the two experiments. 
In the experiments with lampblack and with wood ashes, 
the times taken np in cooling from 70° to 6o° were greater 
than those employed in cooling from 6 o° to 50° ; this most 
probably arose from the considerable quantity of heat con- 
tained by these substances, which was first to be disposed of, 
before they could receive and communicate to the surrounding 
medium that which was contained by the bulb of the thermo- 
meter. 
MDCCXCII. 
K 
