A discussion is given of Robert Brown's original observations of particles
ejected by pollen of the plant \textit{Clarkia pulchella} undergoing what is
now called Brownian motion. We consider the nature of those particles, and how
he misinterpreted the Airy disc of the smallest particles to be universal
organic building blocks. Relevant qualitative and quantitative investigations
with a modern microscope and with a "homemade" single lens microscope similar
to Brown's, are presented.Comment: 14.1 pages, 11 figures, to be published in the American Journal of
Physics. This differs from the previous version only in the web site referred
to in reference 3. Today, this Brownian motion web site was launched, and
http://physerver.hamilton.edu/Research/Brownian/index.html, is now correc
