that connects the Volume of a Liquid with its Temperature, 407 
By the formula, 
r= 24745, 
g=611°28, 
also 5=101; hence ph= "=", and log wh=2'56247. Thus 
we obtain 
T—247-45 1 5 _ 
[256247] f 
the general expression for the weight in grains of a cubic inch 
of the saturated vapour of mercury at T° (C. A. G.), temperature 
reckoned by Centigrade Air-thermometer from the zero of 
Gaseous tension. 
§ 12, The weight of a cubic inch of mercury at 0° is 87544 
grains, hence 
| 
37544 _ § 3811-05 — (T—273:89) | 480 ; 
v tL Mx8811:05 —? 
1°489 
and M= (aera) ; hence 
Ree cit ate 
[8:25857 | a el 
the weight of a cubic inch of mercury in grains at T° 
(C. A. G. temperature). 
We may thus find the temperature at which a=W, or that at 
which liquid and vapour would be of equal density if the laws 
were maintained. 
With alcohol, ether, and sulphate of carbon, transition occurs 
a few degrees below the theoretical temperature of equal density. 
II. Alcohol. 
— § 18. M. Regnault’s observed tensions of saturated vapour :— 
At 40° C. the tension is 134°1 millims.; at 70°, 589°2 millims. 
40 +. 0°48 + 27389 =314'37 C.A.G.=T, | logh= 2°15392 
70+ 0:41 + 27389 = 34430 =T,f  g=190-70 
ao = 3:5892 
This gives 78°83 C. A. as boiling-point at pressure 760 millims. 
M. Pierre’s observations on the expansion of aleohol were made 
on a specimen that boiled at 78°°63 C. A. under pressure 758 
millims., and its specific gravity at O° was 0°8151. 
The following are his second series of observations computed 
with the above index, 3°5392 :— 
