Heike Kamerlingh Onnes (21.09.1853—21.02.1926) was a Dutch physicist and a member of the Royal Netherlands Academy of Arts and Sciences. He was born in Groningen. He graduated from the University of Groningen (1876). He furthered his studies under G. Kirchhoff and R. Bunsen in Heidelberg. In 1878 — 82 he worked at the Delft Polytechnic, and in 1882—1923 he was professor at the University of Leiden and the founder and director (1894—1923) of the cryogenic laboratory (now the H. Kamerlingh Onnes Cryogenic Laboratory in Leiden). His research was in the field of low-temperature physics and superconductivity. In 1892 — 94 he built a high-output cascade liquefaction plant for oxygen, nitrogen and air. In 1906 he obtained liquid hydrogen. He was the first to reach temperatures close to absolute zero, and he studied the properties of many substances at ultralow temperatures. He developed a method of producing liquid helium, and in 1908 he was the first to obtain liquid helium and to measure its temperature (Nobel Prize, 1913). He went on to carry out a series of measurements to refine this temperature, obtaining the values 4.25 K (1911) and 4.42 K (1922). He measured (1911) the critical point of helium (Tk = 5.20 K, pk = 2.26 atm), and in 1909 he reached a temperature of 1.04 K. He measured the viscosity of liquid helium and found that it is greatest at 2.2 K; he measured the density of liquid helium and of its vapour, its specific heat capacity, and, together with L. Dana, the latent heat of vaporisation. In 1911 he discovered superconductivity in mercury, and then in tin, lead, thallium and other metals. In 1913 he found that superconductivity is destroyed by strong magnetic fields and currents. In 1924 he showed that a persistent current can be set up in a ring made of two different superconductors in contact. He was the first to propose the use of a superconducting winding to produce a very strong magnetic field. He proved himself a major organiser of science who began a new approach to the planning and direction of scientific research, and his laboratory became a model of its kind for the research institutes of the 20th century. In 1901 he founded at the laboratory a school for instrument makers and glass blowers, and the scientific journal “Communications from the Physical Laboratory of the University of Leiden”. A foreign member of the USSR Academy of Sciences (1925).