CARVALHO E SAMPAYO, Diogo de (1750-1807). Tratado das Cores que consta de tres Partes Analytica, Synthetica, Hermeneutica. Malta: Joao Mallia, 1787. Rare first edition ' the last recorded auction appearance dates to 1959 (RBH) ' of the Tratado das Cores (1787), the first of two works that Francisco de Carvalho e Sampayo dedicated to colour theory. Written during his stay in Malta, the treatise presents a system based on six generic colours (white, black, yellow, red, blue, and green), combined into linear scales with intermediate degrees. This rational and visual approach to colour classification anticipates 19th-century models and also influenced Goethe, who discussed its theories in his Theory of Colours (1810). 4to (280 x 210mm). 18 hand-coloured copper-engraved plates, of which 2 folding (scattered but light dampstaining and waterstaining). Bound in contemporary half vellum with patterned paper sides (severe water damage). (1)