Universiteit Leiden LION


A visit to the coldest place on earth

Harm Kamerlingh Onnes, 1921 (Museum de Lakenhal, Leiden)

The physics laboratory in Leiden became the "coldest place on earth" under the direction of Heike Kamerlingh Onnes (1853-1926). Helium was first liquefied there in 1908 and three years later mercury became the first metal to be cooled to the superconducting state. The old liquefactor (shown below in a photograph from 1919) can still be admired as you enter our building. The painting above (by Heike's nephew Harm) depicts a more abstract view of the apparatus.

Heike Kamerlingh Onnes (far right) shows his helium liquefactor to three theoretical physicists: Niels Bohr (visiting from Kopenhagen), Hendrik Lorentz, and Paul Ehrenfest (far left)

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