Corrections of the Nitrogen Scale. 537 
experiments on nitrogen, and the numerical equation is 
/' 147-95 
K= J (0-001410- ±*™) 
(23) 
The unit of pv is here taken to be the value that pv 
approaches at the ice point as the pressure approaches zero, 
and # is taken equal to 273'2. 
7. Constant- Volume Corrections for Nitrogen, 
Equations (20) and (23) have been used to compute the 
difference of the two nitrogen scales and thence the thermo- 
dynamic corrections of the constant-volume scale. In this 
latter process the constant-pressure corrections given in 
Table V., column 5, were used. A comparison of results is 
given in Table VI. and, graphically, in Plate XVII. Carve A' 
represents Berthelot's values ; curve B/, those just computed ; 
curve C, Callendar's values. If B 2 had been used as a basis 
instead of B b we should have had another curve B 2 ' lower 
than B/ by the same amount as B 2 is lower than B : . 
Table VI. 
Constant-Volume corrections for Nitrogen at high 
temperatures. p o =1000 mm. 
(The corrections are to be added to the constant-volume reading 
t°C. 
Callendai 
Berthelot. 
Buckingham 
(equ. 14). 
200 
400 
450 
600 
800 
1000 
1200 
055 
0489 
: 646 
0046 
0-194 
0-56 
077 
0-024 
0439 
0-306 
0-514 
0734 
0-961 
We have thus, for each of the two nitrogen scales, the 
independent results of three writers using different methods 
of computation. The various values of the thermodynamic 
corrections show an agreement, for each scale, which is closer 
than has been attained in independent determinations of high 
temperatures with the gas thermometer, and it seems probable 
that the means of the values represented by curves A, B,, and 
C, or A', Bx' and C of Plate XVII. give very nearly the true 
values of the corrections in question. 
