( 324 ) 
Equation (4) after division by 2 p yields: 
1 1 
Phy bh, PEED +g) $k, DEGO ELD GP) (5) 
0 
where for completeness I have not regarded the order of the differ- 
ent terms. Also taking equation (3) once for v, and once for v, and 
adding together, yields: 
Phy bh, PEAP? +e") +h, DD HIG) HD" +6 DD HP") +...(6) 
and subtracting and dividing bij 2 @ gives 
O=k, HP HAB PHP) HAL DPL) . . . (YD 
while the, at least to a first approximation simpler equation: 
1 
0 Sh + Rhy Dak, Cs ; 7) EEE 
follows from (5) and (6). 
The equations (6), (7) and (8) now determine the quantities P,‚p 
and p,—pk; for we find: 
bo 
Bed hy, nn ry 
=O ©) 
80 
D 1 1 k 2 ky, Pe T Ti) 1 (10 
C — == a —_— - — . . . 
"30 3 : 5 kyo ; 
PPE Re (TT) ee 
Along the border curve v = vr + ®+ p‚ so that we may write the 
equation of the border curve: 
0 = (v—»)? — (ver) B+ B*—g’,. . . . (12) 
and to the first approximation this represents a parabola ’). 
1) Just as v. p. Waats (Arch. Néerl. (1), 28, 171) from the reduced equation 
St aelt 
ob SEP fan es has derived 3 (v,—v,) = 2 V2 (1—+), I have also 
~ 
derived 4 (eg +v)) from the same equation by means of the reduced formula (10) 
and have found for it: 
3 (v9 + 4) =1 47,2 (14), 
whence, if p; and s, stand for the liquid and vapour densities : 
4 (po + 6s) = pe [1 +0,8 AH] 
From Amacar’s data for carbon dioxide I find: 
A=} (92 + py) = 0,464 4- 0,001181 (Te — T), 
or reduced 1 + 0,775 (1—t), and for isopentane (S. Youne’s data) 
A= pr [1 + 0,881 (1—1)]. 
The above equation of state, therefore, represents the diameter numerically in a 
satisfactory manner. 
2) The same problem with regard to » has been treated by v. p. Waats (loc. cit.) 
in a somewhat different way; only p is determined accurately by his method and 
the border curve can be derived from his formulae only to a first approximation. 
— ET 
a 
