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
Wander Johannes de Haas de Haas started paralegal studies in 1895. After completion of two of three parts of the examinations and having worked in a lawyer's office for some time, he decided to change career and become a physicist instead. After passing the qualifications exams for admission to University, he started to study physics at the University of Leiden in 1900 under Heike Kamerlingh Onnes and Johannes Petrus Kuenen. He earned his doctorate in 1912, under Kamerlingh Onnes, with a thesis entitled: "Measurements on the Compressibility of Hydrogen." After getting his degree, de Haas worked in Berlin as a researcher at the Physikalische