โ Scribed by W.H Keesom; Miss A.P Keesom
No coin nor oath required. For personal study only.
The thermal properties of liquid helium are described by means of two diagrams which represent p (pressure) or p (density) as functions of T (temperature). A table is also given for p as a function of T and p.
Diagrams have been derived for the first differential coefficients:
(~p/ap)r, (~p/OT)p and (~p/~T)p. These diagrams clearly show the discontinuities which occur in the differential coefficients when passing the )~-curve. ยง I. Inlroduction. In a couple of previous communications i) we dealt with the results of measurements concerning the isopycnals of liquid helium between 1.15 and 4.2 ยฐ K. and up to 35 atmospheres. It seemed interesting to combine these results, the more so as we so get a complete survey of the thermal properties of a substance in which a transition of the second order 2) occurs. As a result we give in this paper a p,Tand a p,T-diagram (p= density) for the considered region. We add three diagrams for the first differential coefficients, from which the compresibility, the tension coefficient, and the expansion coefficient can be easily derived. ยง 2. Diagrams o/state. From the data of Comm. Nos. 224d and e we first derived isothermals in a p,p-diagram, scale 1 atm = 5 cm, 0.001 g/cm 3 = 2.5 cm. As this diagram does not remain sufficiently clear when reduced for printing we do not reproduce it here. From this diagram a new p,T-diagram (isopycnals) for regular values of the density, and a p,T-diagram (isobars) were derived. By comparing these three diagrams the data could be smoothed. From the p,p-diagram we read the figures collected in Table I.
๐ SIMILAR VOLUMES
The authors determined isotherms of helium at liquid helium temperatures, up to densities near those of the saturated vapour. Table II gives the virial coefficients. The second virial coefficient, B, is compared with the results of computations made by Massey and Bucking ham, by De Boer and Michelsa