OF GASES AND VAPOURS. 197 
By k(1+e?') p 
Sone mars 
and thence 
k(1 + a?) > ee 
oe ae 
t—t= - ik Be pealad Tee (1.) 
en 
a Po 
This formula gives the increase of temperature which originates 
from the compression. The density of the gas may then be cal- 
culated from the formula 
{eos : 
’= Fatal)? 
the degree of the condensation is obtained from 
g _ p(l+at) | 
Ae — pltaty’ OF aie oe! © . ae Bee ve (2.) 
We have for atmospheric air, when py, is made equal to the 
pressure of one atmosphere, 
b= 0267; k=7955; a= 0003668; a= 374. 
On substituting these values in the equation (1.), and at the 
same time substituting Briggs’s logarithms for those of Napier, 
we obtain ' 
0°180 (272°7 + 4) .log 2 
Spot eee ee Pe 
0:267 — 0180. log 
Po 
For ¢ = 0° and p = py = 1, we obtain, according to these for- 
mulz, for the pressures of 2, 3, 4,5 and 10 atmospheres, the 
following increase of temperatures and condensations : 
pi=2p, 3p, 4p, 5p,  10p. 
t!= 694, 129°, 186°, 243°, 563°. 
U 
3 =1:59, 2°04, 2°38, 2°64, 3°26. 
The increase of the temperatures is greater than results from 
the formula given by Poisson. There exist on this subject no 
experiments which are in any degree trustworthy. 
10. When air is compressed and then allowed to cool until it 
has again assumed its former temperature, the quantity of heat 
4 — 7 given off is equal to 
k(1 + at) p 
a iP Regt mii eo @ ee oie: (4:) 
