Liquid helium of liquid water. Helium was first liquefied on July 10, 1908, by the Dutch physicist Heike Kamerlingh Onnes at the University of Leiden in the Netherlands. At that time, helium-3 was unknown because the mass spectrometer had not yet been invented. In more recent decades, liquid helium has been used as a cryogenic refrigerant, and liquid helium is produced commercially for use in superconducting magnets such as those used in magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), Magnetoencephalography (MEG), and experiments in physics, such as low temperature Mössbauer spectroscopy. The temperature required to produce liquid helium is low because
Museum Boerhaave to me in 1921. P. Ehrenfest. ' Museum Boerhaave Museum Boerhaave is a museum of the history of science and medicine, based in Leiden, Netherlands. The museum hosts a collection of historical scientific instruments from all disciplines, but mainly from medicine, physics, and astronomy. The museum is located in a building that was originally a convent in central Leiden. It includes a reconstructed traditional anatomical theatre. It also has many galleries that include the apparatus with which Heike Kamerlingh Onnes first liquefied helium (in Leiden), the electromagnet equipment used by Wander Johannes de Haas (a Leiden physicist) for his low-temperature