In 1766, Moses Harris published The Natural System of Colours to demonstrate that one could create the full spectrum of colors by combining three primitives: red, yellow, and blue. As a design exercise, Nicholas Rougeux recreated the color wheels using digital tools. The full color palette as hexadecimals is available at the end.
The Library of Congress has scans if you want to check out the original.
Tags: color, Moses Harris, Nicholas Rougeux, recreation