645 
from the curves for ¢ slightly greater than 3 (ay and 4, const), for g=4, 
and for ¢=5 were all found to be relatively small. With the expe- 
rimental material at present available for this gas it is difficult to settle 
the question as to which of these three values gives the best agreement 
(cf. Fig. 1). An extension of the temperature region for which B is 
known for argon, particularly towards the region of lower temperatures, 
as is already contemplated by KaAMERLINGH ONNEs and CROMMELIN, 
will be (ef. Fig. 1) of the greatest assistance in settling the point. 
b. From Fig. 1 5) it is evident that the best agreement is obtained 
for hydrogen below the Boynu-point (see in particular the points 
representing the lowest three temperatures) on putting g = 4. (Compare 
fig. 1 of Suppl. N°. 25, on which may be placed fig. 3 of the same 
o 
2a 2 paper for the argon points so as to 
= ed Er rg exhibit the degree of agreement for ¢ 
Sony En os | jg slightly greater than 3). Hence, as 
KE lt oh on far as Bis concerned, the behaviour 
EE | of hydrogen below the Boyuw-point 
Ae ‘a appears to be in pretty good agree- 
me lie | ment with the assumption of rigid 
AN spheres of central structure with an 
— eB + attraction potential®) proportional to 
& | \ —r-4, 
Sete . If we assume that, as far as B 
22) is concerned, hydrogen behaves in 
Dee a manner similar to the monatomic 
56 Mbyrogen ae not only (as in Suppl. N°. 25 
oon RS § 3d) witbin that region of tempera- 
ae ture corresponding to the respective 
| | - observational region for argon, but 
lore ler lor leg bp a = 
also towards lower temperatures, 
so that the series of argon points 
Seo may be supplemented by means of 
WEES 
(ges) (gr GS) 
the others. As the calculations of the present paper may be regarded as another 
method of adjusting the virial coefficients, it seemed more reasonable to effect a 
direct comparison of the equation with the individual values. Comparison of the 
deviations occurring in this method which are independent of the adjustment to 
the empirical temperature polynomial, with those obtained by the latter method 
can then afford a basis of judging whether the deviations are greater or less than 
the degree of accuracy of the observations (cf. p. 646 note 1). 
1) In this the point log 7 = 2,0, log BN = 6,5 — 10 for H, coincides with the 
point log hu=9,551 —19, Hz = 9,488 —10 when q=4, and with the point 
log hv = 9,815 — 10, Fz = 9,495 — 10 when q =5. 
2) BRAAK, Diss. Leiden 1908, p. 85, finds for Hg at these low temperatures a 
