- Leiden scale
The Leiden scale was used to calibrate low-temperature indirect measurements in the early twentieth century, by providing conventional values (in
kelvin s, then termed "degrees Kelvin") ofhelium vapour pressure . It was used below -183°C, the starting point of theInternational Temperature scale in the 1930s (Awbery 1934).It probably goes back to around 1894, when
Heike Kamerlingh Onnes ' cryogenic laboratory was established inLeiden ,Netherlands .It has been reported [Hubbard, Joanna; [http://tea.armadaproject.org/hubbard/4.3.2000.html Are icebergs made of salt water or fresh water?] (
April 3 ,2000 )] that the scale is the kelvin scale shifted so that theboiling point s ofhydrogen andoxygen become zero and 70 respectively, but this is unlikely to be true. Oxygen under astandard atmosphere boils at a temperature in the 90.15 to 90.18 K range. For hydrogen, it depends on the molecular variety. The boiling point is 20.390 K for "normal" hydrogen (made up of 75%orthohydrogen and 25% parahydrogen) and 20.268 K for pure parahydrogen. Under the purported definition,absolute zero would lie at -20.15 ÐL ["Leyden scale" at [http://temp-scales.org/obsolete.html Temp-scales.org] ] .External links and references
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- Berman, A.; Zemansky, M. W.; and Boorse, H. A.; [http://prola.aps.org/abstract/PR/v109/i1/p70_1 "Normal and Superconducting Heat Capacities of Lanthanum"] , Physical Review, Vol. 109, No. 1 (January 1958), pp. 70-76. Quote:
#:« The 1955 Leiden scale13 was used to convert helium vapor pressures into temperatures [...] (13) H. van Dijk and M. Durieux, in "Progress in Low Temperature Physics II", edited by C. J. Gorter (North-Holland Publishing Company, Amsterdam, 1957), p. 461. In the region of calibration the 1955 Leiden scale, "TL55", differs from the Clement scale, "T55E", by less than 0.004 deg. » (emphasis added)
# Grebenkemper, C. J.; and Hagen, John P.; [http://prola.aps.org/abstract/PR/v80/i1/p89_1 "The Dielectric Constant of Liquid Helium"] , Physical Review, Vol. 80, No. 1 (October 1950), pp. 89-89. Quote:
#: « The temperature scale used was the 1937 Leiden scale. » (emphasis added)
# Awbery, J. H.; [http://ej.iop.org/links/rBN0TrIu4/oMvHcjH_2xGtgmnTav5vpA/rpv1i1p161.pdf "Heat"] , Rep. Prog. Phys. 1934, No. 1, [http://www.iop.org/EJ/abstract/0034-4885/1/1/308/ pp. 161–197] doi:10.1088/0034-4885/1/1/308. Quote:
#: « It should be mentioned that below -183°C, the Leiden workers do not entirely agree with some of the other cryogenic laboratories, but use a scale of their own, generally known as the Leiden scale. » (emphasis added)- Berman, A.; Zemansky, M. W.; and Boorse, H. A.; [http://prola.aps.org/abstract/PR/v109/i1/p70_1 "Normal and Superconducting Heat Capacities of Lanthanum"] , Physical Review, Vol. 109, No. 1 (January 1958), pp. 70-76. Quote:
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