Leiden University at the university. The learning and reputation of Jacobus Gronovius, Herman Boerhaave, Tiberius Hemsterhuis and David Ruhnken, among others, enabled Leiden to maintain its reputation for excellence down to the end of the 18th century. At the end of the nineteenth century, Leiden University again became one of Europe's leading universities. At the world’s first university low-temperature laboratory, professor Heike Kamerlingh Onnes achieved temperatures of only one degree above absolute zero of −273 degrees Celsius. In 1908 he was also the first to succeed in liquifying helium and can be credited with the discovery of the superconductivity in metals. The
Einstein's Sink Einstein's Sink Einstein's Sink is an antique sink that has been in use by the physics faculty of Leiden University since 1920. Originally the sink stood in the large lecture room of the old Kamerlingh Onnes Laboratory. It was taken to the new building when the physicists moved to the Leiden Bioscience park in 1977. Here it still stands in the current large lecture room (The De Sitterzaal of the J.H. Oortgebouw), continuing the tradition of washing the hands of visiting famous scientists. A short list of 'sink users' consists out of Paul Ehrenfest, Heike Kamerlingh Onnes, Hendrik Antoon Lorentz