Robert Brown

Robert Brown was born in 1773 in Montrose, Scotland, the son of an episcopalian minister. He studied medicine at Edinburgh but his passion was botany, and in 1801 he sailed as naturalist aboard the Investigator on Matthew Flinders's survey of the Australian coast. He returned with some 3,400 plant species, most new to science, and spent years classifying them, establishing himself as the foremost botanist of his age.

Brown made lasting contributions to botany proper: he was among the first to recognise the fundamental distinction between gymnosperms and angiosperms, and in 1831, while examining orchid cells, he identified and named the cell nucleus, a structure now central to all of biology.

In 1827, peering through his microscope at pollen grains of the plant Clarkia suspended in water, Brown noticed that tiny particles ejected from the grains danced about ceaselessly and irregularly. Suspecting he might be seeing some life force, he tested the idea rigorously — and found that pollen from plants dead for a century jittered just as much, as did fine particles of ground glass and even rock. The motion, he concluded, was physical, not biological, though he could not say what caused it.

Brown never explained the motion that bears his name; that fell to Einstein and Perrin three generations later. He served as keeper of the botanical collections of the British Museum and as president of the Linnean Society, and died in London in 1858.