ON THE MEASUREMENT OF TEMPERATURE. 
l(i:j 
6, The Vapour Pressures of Liquid Hydrogen on the Constant-Volume Hydrogen 
Scale. 
(I.) Thermometer A (12 cul). centims. bulb). 
Ice-Point of Thermometer, May 7th, 1902. 
Pressm-e on gas 
in thermometer. 
Temperatiu’e of 
dead-space. 
Constant. 
Main thermometer .... 
minims. 
953-05 
°C. 
15-85 
43-679 
The auxiliary thermometer was already filled with helium (Part II., § 11, II.), it 
was not refilled with hydrogen, for when the bulb of the main thermometer was 
cooled in liquid hydrogen boiling under reduced pressure, hydrogen might condense 
in the bottom of the bulb of the auxiliary thermometer. 
Vapour Pressures of Liquid Hydrogen. 
May 28th, 1902. 
Pressm-e on gas 
in thermometer. 
Temperature of 
dead-space. 
Temperature 
of stem. 
Vapour pressures 
of hydrogen. 
Temperature 
i 
Found. Calculated. 
1 
unilims. 
° C. 
° He. scale. 
millims. 
° n. scale. 
° H. scale. 
72-04 
18-3 
40 
757-2 
20-17 
20-21 
66-35 
18-6 
51 
458-6 
18-57 
18-56 
62-40 
18-6 
50 
309-0 
17-45 
17-44 
62-80 
18-6 
45 
321-8 
17-56 
17-55 
58 - 40 
18-8 
56 
198-0 
16-33 
16-35 
(II.) Thermometer B (26 cub. centims. biilli). 
Ice-Point of Thermometer, June 4th, 1902. 
Pressure on gas 
in thermometer. 
Temperature of 
dead-space. 
Constant. 
millims. 
°C. 
Main thermometer .... 
952 - 55 
17-55 
91-9.30 
Auxiliary thermometer. 
954 
17-55 
8-093 
Y 2 
