in Combustion, and in the Condensation of Vapours. 297 
__The naphtha was burned in the same small lamp which 
I had. employed in my experiments made with alcohol and 
sulphuric ether; but as I had not been able to succeed in 
burning the naphtha without smoke, I cannot rely impli- 
citly upon the results of these experiments. Perhaps with 
pure oxygen gas we might succeed in burning it entirely. 
Ihave met with the same difficulty in burning oil of 
turpentine and colophon ; and for this reason I thought, it 
would be useless to detail my experiments with these two 
substances. 
©§ VIII. On the Quantity of Heat developed in the Com- 
. bustion of Tallow. 
_ Having procured tallow candles of a good quality, those 
which are ealled six in the pound, I burned one under the 
calorimeter, taking care to keep it well snuffed, in order to 
avoid smoke. 
The following are the details and results of two experi- 
ments made on the same day (16th of November 1811), 
with one of these candles. 
The capacity of the calorimeter for heat was equal to that 
of 2371 grammes of water. 
f 
re) 
£ 
& 
perature o 
Calorimeter 
y of Water heated 
180° with the Heat de- 
veloped in the Combus- 
Time while the Candle was 
burning under the Calorimeter 
the Water in the 
Quantity of Tallow burned. 
Elevation of the Tem 
| tion of 1 lb. of Tallow, 
| Quantit 
M. S. | Grs.|D.F. 
Ist Experiment .....¢..2.416 2/1°6 |102/84°385 Ib. 
2d Experiment........+++416 50|1°7 |104.82-991 
| 
Mean Result’. .....2.. 83°687 lb. 
We have seen that with ‘ 
white wax the result ve rane 
With purified oil of colsa... 93:073 
- |And with oil of olives...... 90°439 
§ IX. Quantity of Heat developed in the Combustion of 
Charcoal. 
If we could burn under the calorimeter some pieces of 
wood 
