“Further experiments with liquid helium.”

Abstract

In most of the experiments that one would like to make at helium temperatures, it is necessary to transfer the liquid helium from the apparatus in which it has been prepared to another — the helium cryostat — more suitable for holding the apparatus arranged for these special experiments. In Comm. N°. 112 (June 1909) it was mentioned that this was going to be tried; and in the Jubilee book presented to J. M. van Bemmelen it was further stated that the transference had, in fact, been once successfully accomplished. Although the success which attended this operation allowed immersion in the protected helium bath of the apparatus with which it was shown that even at a vapour pressure as low as 0.15 mm. helium is still a liquid, it was nevertheless evident that this desirable result had been obtained only by accident. A method that promises to be more efficient is now being developed, and I hope to be able to make a communication in the near future concerning it.

(Communicated to the Meeting of Dec. 24, 1910).

A. Isotherms of monatomic gases etc. VIII. Thermal properties of helium.