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Brown was born at Montrose, Scotland, on 21 December 1773, the son of an Episcopalian priest. He studied medicine at Edinburgh University but did not obtain his degree. He subsequently held the position of assistant-surgeon in a Scottish infantry regiment, but soon revealed that his true interest lay in botany. In the late 1790s he was introduced to the well-known English botanist Joseph Banks, who allowed him the free use of his library and collections. Shortly afterwards Brown resigned from the army in order to accept the post of naturalist on an expedition under Captain Matthew Flinders, on the Investigator, to survey the coast of the lately discovered Australian continent. He voyaged from 1801 to 1805 and on his return to England published, in 1810, the first part of his studies on the flora he had discovered on his Antipodean journey. The poor sales of the book discouraged him and he left the rest unpublished. In the same year, he was appointed Librarian to Joseph Banks, a post which he held until Banks's death in 1820. Banks bequeathed to Brown the full use of the library and its collections for life. In 1827, in compliance with the stipulations of Banks's will, he agreed to the transfer of the books and specimens to the British Museum and was appointed Curator of the botanical collections there. He died in London on 10 June 1858.

In 1791 Brown submitted his first paper to the Natural History Society. It was a highly detailed classification of the plants he had collected in Scotland, with accompanying notes and observations. This list was to win him many introductions in the scientific world of his day. It was not until 1828, however, that he made one of his greatest contributions to science, published in the Edinburgh New Philosophical Journal. The paper was entitled A brief account of Microscopical Observations made in the months of June, July and August 1827 on the particles contained in the pollen of plants, and on the general existence of active molecules in organic and inorganic bodies and it was in this paper that Brown set out his observations on 'Brownian movement', or 'motion', which perpetuates his name. The concept arose from his observation that very fine pollen grains of the plant Clarkia pulchella when suspended in water move about in a continuously agitated manner. This phenomenon is true for any small solid particles suspended in a liquid or gas and can be viewed in a bright light through a microscope. Brown was able to establish that the constant movement was not purely biological in origin because inorganic materials such as carbon and various metals are equally subject to it, although he could not find the cause of the movement. During his lifetime there was no shortage of theories to explain his discovery, but it was not until the twentieth century that the question was answered.

Brown also published papers on Asclepiadaceae (1809) and on Proteaceae (1810), wrote on the propagatory process of the gulf-weed and on the anatomy of fossilized plants. He also described the organs, and mode of reproduction in orchids. In 1831, while investigating the fertilization of both Orchidaceae and Asclepiadaceae, he discovered that a small body which is fundamental in the creation of plant tissues, occurs regularly in plant cells - he called it a 'nucleus', a name which is still used. Another significant revelation Brown made was the identification of the difference between gymnosperms and angiosperms.

Brown's various papers on his findings and opinions in every division of botanical science made him the outstanding authority on plant physiology of his day, and he did much to improve the system of plant classification by describing new genera and families. His observation of Brownian movement was important in showing how molecular motion forms the basis of kinetic theory.

Author not available, Brown, Robert (1773-1858). , The Hutchinson Dictionary of Scientific Biography, 01-01-1998.

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