The Mystery of the Unceasing Motion: Brown, Einstein, Perrin

Abstract

The Scottish botanist Robert Brown (Fig. 3.1) was a naturalist of the type that appeared frequently in the eighteenth and nineteenth centuries: a scientific traveller venturing to little-explored regions, just like, 30 years later, the Englishman Charles Darwin or the Prussian Alexander von Humboldt. At the age of 27, Brown sailed on board the research ship ‘Investigator’ on behalf of the renowned British botanist Sir Joseph Banks to New Holland, the present Australia, where until 1805, he collected 4,500 plant species, 1,700 of them hitherto unknown. Brown remained widely known beyond his field, not because of that collection but rather through an observation he made 20 years later.