348 DR. S. CHAPMAN ON THE LAW OF DISTRIBUTION OF MOLECULAR VELOCITIES, ETC. 
Sutherland’s constant S. —These values are those given in the same table of my 
former memoir (what is called S in this paper was there, and is usually, denoted by C), 
where references to sources may be found. The value for krypton was there given 
incorrectly ; I am indebted to Dr. G. Rudorf for the correction. 
van der Waals’ b .—The values for helium (Kamerlingh Onnes), hydrogen, 
nitrogen, air (Rose-Innes), and carbon-dioxide (van der Waals’) are taken from 
Jeans’ ‘Dynamical Theory of Gases,’ 2nd edition, § 194. Those for argon, krypton, 
and xenon (R-amsay and Travers), from Rudorf, ‘ Phil. Mag.,’ June, 1909, 
p. 795, are not direct experimental values, however, but are calculated from critical 
data. 
Diameter 2 v 1 from viscosity .—These are practically twice the values for the radii 
given on pp. 476, 481 of my former memoir, where, however, errors of calculation 
(here corrected) were made in the case of argon and krypton (as Dr. G. Rudorf kindly 
indicated to me). 
Diameter 2 a 2 from van der Waals’ b .—-The value for oxygen, and the second 
values for nitrogen and carbon-dioxide (as well as 2 <r l for the latter) are from Table 7 
of Eucken’s paper ; he does not give his authorities, but his values are probably the 
most recent and reliable. The value for hydrogen, he says, is doubtful. 
PRESENTED 
v sJUiiiaiS 
