The theory of colouring: being an analysis of the principles of contrast and harmony in the arrangement of colours, with their application to the study of nature, and hints on the composition of pictures, etc (1872)
Bacon, J · London, G. Rowney · leaf 9
DIA&RAM or COLOUR ^Y.OffiN CrB£EM
Color
Internet Archive · Cornell University Library · Public domain (published before 1931). Free to use for anything.