What Brown saw and you can too

TL;DR

This paper revisits Robert Brown's original observations of pollen particles, analyzing their nature and misinterpretations, using modern and homemade microscopes to provide new insights into Brownian motion.

Contribution

It offers a detailed comparison of Brown's original observations with modern microscopy, clarifying the nature of the particles and correcting historical misconceptions.

Findings

Brown's particles are not universal organic building blocks.

Modern microscopy confirms the particles' nature and behavior.

Brown's interpretation of the Airy disc was a misinterpretation.

Abstract

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.