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
Pieter Rijke 1836. The title of his Ph.D. thesis was "De origine electricitatis voltaicae". In 1835 he was appointed professor of physics at the Royal Athenaeum in Maastricht. In 1845 he became extraordinary professor and in 1854 he was promoted to full professor of physics at the University of Leiden. There he started a physics laboratory with a large collection of scientific instruments. His most important students were H.A. Lorentz and J.D. van der Waals. He retired in 1882, and was succeeded by Heike Kamerlingh Onnes as professor of experimental physics at the University of Leiden. Rijke became a member of the