Martinus van Marum (20.03.1750-26.12.1837) was a Dutch physicist and botanist. He was born in Delft. He graduated from the University of Groningen (1773). In 1776 — 80 he was a physician in Haarlem, and from 1783 director of the cabinet of the devotees of physics and natural history (later Teylers Museum in Haarlem). His research concerned the study of electrical phenomena and of gases. Carrying out a series of experiments to test whether the Boyle–Mariotte law held for all gases and not only for air, and changing only the pressure of gaseous ammonia, he obtained it in the liquid state. Van Marum's experiments were followed by numerous attempts to turn the known gases into liquids by compressing them. He built a large electrical machine and with its help (more exactly, with the sparks from it) decomposed a whole series of substances (in 1785 and later), in particular ammonia into nitrogen and hydrogen. In 1786 he established the connection between heat and the electric spark.
A corresponding member of the Paris Academy of Sciences (1803).