1062 
a comparison of the net of isothermals of neon with that of argon. 
The values then found by a comparison with argon viz. — 228°.2 C. 
and — 227°.9 C. were, however, obtained using the result of a 
somewhat rough determination of the critical pressure of neon, viz. 
29 atm. '). Repeating these calculations utilising the value now found 
for the critical pressure, the results come out a little lower, namely 
—228°.9 C and --228.°6 C, which values appear to agree very 
satisfactorily with the experimental value. Our supposition expressed 
at the time, which was rendered probable by the course of the 
vapour-pressures in connection with that of the isothermals, that 
argon and neon, looked upon from the point of view of the law 
of corresponding states, differed but little from each other, is thereby 
contirmed in a very satisfactory manner. 
The estimate of the critical temperature of neon obtained at the 
time by a comparison with hydrogen (—231°.2C) deviated much 
more from the observed value. In this comparison use was made, 
however, of the critical temperature of hydrogen, as determined by 
Burre ®), —241°.14 C and, moreover, of our rough determination of 
the critical pressure of neon above referred to: these values have 
now to be replaced by those found by ourselves (for hydrogen as 
will be shown in Comm. N°. 151c we have found 77, = 33°.18 K, 
Or = — 239°.91 C, pr = 12.80 atm). 
The calenlation when corrected in this way gives — 2380°.2 C 
for the critical temperature of neon, a value which deviates much 
less from the result of direct experiment than before. 
Physics. — “The viscosity of liquefied gases. VI. Observations on 
the torsional oscillatory movement of a sphere in a viscous 
liquid with finite angles of deviation and application of the 
results obtained to the determination of viscosities.” By J. E. 
VERSCHAFFELT. (Communication N°. 151d from the Physical 
Laboratory at Leiden). (Communicated by Prof. H. KAMERLINGH 
ONNEs). 
(Communicated in the meeting of February 24, 1917). 
1. In a previous communication *) the theory of the oscillatory 
rotation of a sphere in a viscous liquid was developed on the sup- 
position of the rotation taking place with such small angular velocities, 
1) H. KAMERLINGH ONNes, Proc. XII, 1, p. 175. Comm. N°. 112. 
2) F. Bunur, Phys. Zeitschr. 14, p. 860. 1913. 
3) Comm. N°. 1485. Proc. XVIII 2. p. 840. 
