Heike Kamerlingh Onnes a "Kamerlingh Onnes Laboratorium" named after him, as well as a plaque and several machines used by Kamerling Onnes in the main hall of the physics department. The Kamerlingh Onnes Award was established in his honour, recognising further advances in low-temperature science. The Onnes effect referring to the creeping of superfluid helium is named in his honor. The crater Kamerlingh Onnes on the Moon is named after him. Onnes is also credited with coining the word "enthalpy". Onnes' discovery of superconductivity was named an IEEE Milestone in 2011. Heike Kamerlingh Onnes Professor Heike Kamerlingh Onnes FRSFor HFRSE FCS ( ();
Leiden scale Leiden scale The Leiden scale (°L) was used to calibrate low-temperature indirect measurements in the early twentieth century, by providing conventional values (in kelvins, then termed "degrees Kelvin") of helium vapour pressure. It was used below -183°C, the starting point of the International Temperature scale in the 1930s (Awbery 1934). The Leiden scale probably goes back to around 1894, when Heike Kamerlingh Onnes' cryogenic laboratory was established in Leiden, Netherlands. It has been reported that the scale is the kelvin scale shifted so that the boiling points of hydrogen and oxygen become zero and 70 respectively, but this is unlikely