Ispired by another other thread about race, I tried without success to locate a qoutation I once read.
Before the development of the idea of neutrons and atomic number, there was a great deal of research going on, trying to determine the atomic weight of elements.
This research was giving mixed results, and odd ratios, because scientists didn’t know that they were working with mixtures of isotopes.
“In retrospect, it was like trying to determine the weight of a collection of partially filled jars of water”.
Or something like that — it’s such a lovely image, was it a famous quotation? Ring any bells?