Abstract
IN the Physical Review of January 15, p. 303, S. G. Sydoriak E.R. Grilly and E. F. Hamel report that on October 13, 1948, they succeeded in condensing pure helium-3. This is especially interesting, since several physicists, F. London, Tisza, and others, have expressed doubts that helium-3 would liquefy, Twenty c.c. (measured at S.T.P.) of helium-3 were used, and condensation took place at the bottom of a 1·2-mm. bore stainless steel capillary immersed at a depth of 5-10 mm. in the liquid helium well. Condensation was assumed to be taking place when the equilibrium pressure in the capillary was independent of the volume of helium which remained in the mercury manometer connected to the room-temperature end of the capillary. From the data obtained, 3·34°K. was chosen as the. critical temperature of helium-3. The vapour pressure measurements showed that at 1·2°K. the vapour pressure of helium-3 was thirty-five times that of helium-4 ; helium-3 was suitable for thermometry at low temperatures down to 0·5° K. and perhaps lower ; the normal boiling point of helium-3 was 3·2°K., and by extrapolation to the critical temperature the critical pressure was 875 mm. of mercury. A value of 0·O41 gm./c.c. for the critical density was deduced.
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Liquid Helium-3. Nature 163, 477–478 (1949). https://doi.org/10.1038/163477d0
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DOI: https://doi.org/10.1038/163477d0