SPECIFIC HEAT OK CASES. 
191 
he specific heat of water being 
- 1 0000 
hat of air is - - 
,iecond experiment gave - . - 
- 0-2dti0 
- 0 2530 
Medium 0’24g8 
§ 2 . 
Si-cond Method. 
Tlie second method cl' ascertaining the proportion of St roud me- 
e specific heat of air to that of water, consiaieJ in deter- **’'*‘^‘ 
lining, by calculation, the real quantity of heat lost in a given 
ne by the calorimeter, when the current of hot air had ren- 
red the temperature stationary.- It is, in effect, evident, that 
len arrived at this point, the calorimeter loses a qiiaiftity of 
:at equal to that communicated by the current. These are 
j bases of the calculation, applied to the experiment made on 
‘i air, and presented in the first table. 
\We know exactly the quantity of copper and tin employed 
ibe composition of our calorimeter, and the quantity of water 
lutch it contained. Its w'hole mass contained as much heat as 
t6‘8 grammes of distilled water. 
(On the other hand, we have ascertained by a very careful 
pjeriinent, that if, after the current of hot atmospheric air has 
Bssed the temperature of the calorimeter to rise to a stationary 
imt, we stop the current and leave the calorimeter to the 
cs air, it will lose, in twenty minutes, a heat capable of low- 
ing its temperature 2°8S7. This number of degrees is not 
quantity sought, because, in that experiment, thequicknest 
I the cooling will decrease every instant. But this experi- 
icit, by means of an e.tsy calculation, may lead us to discover 
quantity of heat lost, if the quickness of the cooling had, 
itig the twenty minutes, been the same as it was in the 
instant. This quantity being repre»cuted by S, we have 
A 
S=A log. hyp. — . 
B 
!■ 
