(164 ) 
» from the zero point to the surface of the meniscus in the gras 
duated leg of the U-tube ') 
B the pressure on the outer meniscus of U-tube 
H the height of the top of the meniscus in the outer above the 
top of that in the graduated limb 
expressed in cms of mercury at 0.0° C. at Leiden. 
h,h' the capillary depressions of the menisci in the graduated and 
outer limbs of the U-tube 
A the pressure of 1 atmosphere. 
Then neglecting the differences in PV, due to the difference 
between the pressure at the mercury meniscus in the graduated limb 
of the U-tube and A, and also the difference between this pressure 
and the mean pressure of the gas together with the change in the 
mean expansion coefficient ay from 0.0° C to the various tempera- 
tures we have 
ae ee est V; | V's a 
(ltaynt, 1+ enit's 
5 a Ee A Viste | 
+ant's 1 + ants} 
which is more convenient for calculation when written 
Boa = en Vs Ho He") 
=S | 4 —v)— 
Vee a ea oe 
where: Va, Var 45 Z are the volumes of the various parts at 
17° C. found by calibration and 
n= Vi ant), t5 = 11 Veen, 14 = Vianty, 0 = Vak (ts Tijn 
where k is the expansion coefficient of the glass and 
n= ll) he EPMO 
The last corrections can be fone tabulated. 
2. The measurements at higher pressure. In this calculation we 
may neglect the corrections for the capillary depression in the gra- 
duated tube 5, (the inner diameter is about 0.6 c.m.), and for the 
pressure of the gas due to its own weight, which corrections can 
easily be applied to the result if necessary. 
The volume of gas under the pressure p at the surface of the 
meniscus in b4 is divided into four parts each at its own temperature 
1) The volume of the supplements of the menisci used are all determined after 
Comm. N° 67, I. 
