o 414 
applied in the manner published in Comm. N°. 97a § 8. For this, the 
temperature distribution along the stem was taken from Comm. N°. 95e. 
That this temperature distribution is approximately correct was 
apparent, moreover, from the time it took pressure equilibrium to 
be established. Cf. Comm. N°. 127a. 
Collecting all these, we may regard the volumes occupied by the 
cooled gas as certain to within 1 in 10000. Allowing for what we 
have already stated regarding the pressure, but not taking tempera- 
ture uncertainty into account, we may expect an accuracy of 0,00002 
in the pv's, or, at the highest pressure to within one fivethousandth, 
and at the lowest pressure, to within */,,,.'° of the value of pug. 
§ 6. Calculation and Results. The quantities of gas were always 
expressed in terms of the normal volume. For this purpose equation 
I of Comm. N°. 127a was used: 
pv A200 == 1.07258 + 0.000667 dyaoor. 
Using, where necessary, an approximate temperature as a correc- 
tion factor for the piezometer, the measurements vielded values of 
d4, the density of the gas in the piezometer under the observed 
pressure. The temperature of the gas in the piezometer for each 
series was obtained from the pv4 itself for that particular series. 
For that purpose values of C4 in 
pug = Ag + Bada + Cada” 
were used in the calculation which were obtained for each (at first 
approximate) temperature from the special reduced equation of state 
for hydrogen VIL.H,.8 given in Comm. N°. 109a equation (16) 
which was deduced from the observations of KAMERLINGH ONNES and 
Braak and adjusted to a temperature of — 217°C. Ay and By 
then follow from our observations and also pra at the same tem- 
perature for the density of the gas in the hydrogen thermometer of 
1100 mm. zero pressure. From this with 
(pv )ts = (pva), (1— 0.0036627 t‚) 
we finally obtain the temperature on our hydrogen thermometer of 
1100 min. zero pressure. 
The temperatures obtained in this way yield a calibration on the 
hydrogen scale of the resistance thermometer whose readings serve 
as a guide to the regulation of the temperature of the bath. This 
resistance thermometer was also calibrated with the hydrogen ther- 
mometer independently. The two calibrations are not quite in agree- 
ment. A subsequent paper by KAMBRLINGH Onnes and Horst will 
return to the question of this difference. 
We obtained (where ¢, is the temperature on our hydrogen ther- 
mometer of zero pressure 1100 mm.): 
