Featured on PDR in the collection Synaesthesia’s Colour Debut (1883)

Victorian polymath Francis Galton is known as the inventor of many things: the world’s first weather and isochronal climate maps; the statistical concepts of correlation and regression toward the mean; the ultrasonic whistle; and — with a more harmful afterlife — many aspects of the field he named “eugenics”, as well as its supposed application to criminology. An indefatigable student of physical appearance, who is remembered (and often reviled) for a fanatical dedication to hegemonic British imperial norms of behavior and appearance, Galton also turned his curiosity to the inner world and its perceptions. Pioneering research into the visual-spatial complex known as “number form” — in which individuals experience numbers as possessing distinct spatial properties — Galton published the very first color plate of synaesthetic…