Moses Harris (15 April 1730 – 1787) was an English entomologist and engraver. Life and work Harris was encouraged in entomology from a young age by his uncle, a member of the Society of the Aurelians. In 1762 he became secretary of a second Society of Aurelians. He was a skilled artist, displaying some of his insect drawings at the Royal Academy in 1785. He drew and engraved illustrations for books including Dru Drury's Illustrations of Natural History (3 volumes, 1770–1782) and John Coakley Lettsom's The Naturalist's and Traveller's Companion (1772). Colour theory In "The Natural System of Colours" published in 1766, Harris discussed the multitude of colours that can be created using three "grand or principle" colours: red, yellow and blue. As a naturalist and an engraver, Harris focussed on the relationships between colours and how they are coded and created. He explained how three colours can be íntermixed, tinted and shaded to create 660 colours "materially, or by the painters art". Harris referred to red, yellow and blue as "Primitives" and attempted to link these to Isaac Newton's colour theory by making reference to colours "seen in the rainbow refracted by the prism". "The Natural System of Colours" features two illustrations and the first of these is Harris' 'Prismatic' colour wheel which features red, yellow and blue as the key principle colours. These colours sit at the centre of the colour wheel surrounded by variations of 'Mediate' colours, orange, green and purple. The second illustration in "The Natural System of Colours" is Harris' 'Compound' colour wheel which features orange, green and purple at the centre surrounded by variations of tertiary colours between each of the 'Mediate' colours. Harris conflated the creation of colour using pigments with the creation and appearance of colour in respect to light-waves in two ways. Firstly, in his attempt to deal with black and white. He suggested that the admixture of opposing colours create "a dirty unmeaning colour" and he contended that the admixture of red, blue and yellow "in equal force and in the strongest powers which by violently opposing each other and in very unequal contest are all three continually defeated, causing a total confusion and obscurity in darkness", thereby suggesting that these three colours create black. In reference to this claim, the centres of each colour wheel feature three overlaid colours (red, yellow and blue, and orange, green and purple) outlined