I had been searching for something geometry-related when I found the Euclid book in the last post so when I found the Public Domain Review I wondered if they had anything else about the subject. Turns out they do, and I found this fascinating and somewhat bonkers book from 1887, Geometrical Psychology. Nothing to do with what I was looking for, but it has some remarkable illustrations in it where the author attempts to diagram the evolution of human consciousness. Some of my favourites:
The back of the book also has several pages of adverts for other works available from the publisher, and just the titles alone are fun to read through. Some of my favourites again:
Lunacy, drugs and booze! I’d imagine this was a rather popular set of publications.