London, Taylor & Francis, 1861 ["1860"]. 4to (30.0 x 23.2 cm). 28 pp.; two engraved plates. Later marbled boards with printed label mounted on the front board.

The definitive publication by James Clerk Maxwell (1831-1879) on his theory of colour, in which the mixture of three primary colours are sufficient to account for all perceived hues. "Maxwell contributed to the field of optics and the study of colour vision, creating the foundation for practical colour photography. From 1855 to 1872, he published at intervals a series of valuable investigations concerning the perception of colour, colour-blindness, and colour theory..." (Wikipedia). The two plates a bit foxed in the margin, otherwise a very good, clean copy.