When you realize that Einstein's Brownian motion paper is really an equipartition theorem argument

Reading the paper reminds me why I dislike historically-driven Modern Physics. How many of us have heard the folk wisdom that Einstein's paper on Brownian motion (translation: http://users.physik.fu-berlin.de/~kleinert/files/eins_brownian.pdf) allowed the first measurement of Avogadro's Number? But wait, what's this?

We tend to get hooked by clean historical narratives of the evolution of science that do not accurately reflect the state of knowledge at the time, or the significance of results as seen by contemporaries.

For what it's worth, the rough size of air molecules (the several-angstrom range) and the number per unit volume had already been estimated in 1865 by Loschmidt, see https://web.archive.org/web/20060207130125/http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Loschmidt-1865.html

Another historical note: the 1926 Nobel for Jean Perrin (who did various measurements of Avogadro's Number) kind of reminds me of precision measurements in particle physics: the best evidence for atomic theory was different measurements of Avogadro's Number gave the same answer.

( https://www.nobelprize.org/prizes/physics/1926/ceremony-speech/)