326 
DR. E. H. GRIFFITHS AND MR. EZER GRIFFITHS ON THE 
While it was not possible to compare our thermometers with a standard, the 
observations in liquid oxygen supplied data for calculating c, taking the boiling-point 
of liquid oxygen on the gas scale as —182°'97 C., thus connecting our scale with 
that of the platinum thermometer which Henning had calibrated by means of the 
gas thermometer. 
Table I. below summarises some of the fundamental quantities for the various 
thermometers :—- 
Column I.—The letters designate the various thermometers. 
Column II.—The mean coefficient between 0° C. and 100° C., denoted by a. 
Column III.—The constant of the parabolic formula 
= —} 
r Ivioo / too] 
as determined by the sulphur point. 
Column IV.—Pt (oxygen), the boiling-point of oxygen on the platinum scale. 
Column Y.—The difference between the boiling-point of oxygen by the gas 
thermometer and the value deduced from the parabolic formula 
given above. 
Column YI.—-The constant c of equation 1, connecting the thermometer with 
Henning’s standard. 
Table I. 
I. 
II. 
III. 
IV. 
Y. 
YI. 
Thermometer. 
a x 1CF. 
3. 
Pt (oxygen). 
Difference. 
c x 10 5 . 
Q 
0-38598 
1-514 
- 192-37 
1-56 
+ 0-07 
AA 
0-38591 
1-534 
- 192-60 
1-68 
-0-34 
AB 
0-38899 
1-508 
- 192-63 
1-85 
-0-39 
CD 
0-38888 
1-501 
- 192-71 
1-99 
-0-53 
Henning’s standard platinum thermometer gives a difference of 1°'74 C. from the 
gas scale at the oxygen point. 
The values of the constant c for the different thermometers examined by him vary 
from — 0'68 to +0'11. 
The quantity with which we were most concerned, however, was not the exact 
