Robert Brown was looking at a CELL NUCLEUS through a microscope.
Robert Brown (1773-1858) was a Scottish botanist. Studying the cells of plants, he called the ovals inside those cells the "nucleus" as he watched the interaction of pollen with the cell nucleus. The small, random oscillations of particles in the fluid of the cell are given the name "Brownian motion" based on the sort of fluctuating movement that Brown observed.
