One of my bots (firstname.lastname@example.org) recently surfaced this beautiful French book published in 1839 on the topic of color perception. "De la loi du contraste simultané des couleurs" by Michel Eugene Chevreul.
You can browse the whole thing at the Internet Archive:
terry died one year ago today, proceeds from hats go towards the national alliance of mental illness and the BBRFoundation
theres a bunch of hats too you dont have to copy me