CASTEL, Louis B. L'Optique des Couleurs, Fondée Sur Les Simples Observations, & Tournée Surtout À La Pratique De La Peinture, De La Teinture & Des Autres Arts Coloristes. , xviij, 487,  pp. Illustrated with 2 leaves of plates. 12mo., 165 x 92 mm, bound in contemporary speckled calf, gilt spine, red edges. Paris: Chez Briasson, 1740.
First Edition. A fine copy of this important early book linking colour and music by the French mathematician Louis Castel, whose main claim to fame is the clavecin oculaire. This ocular harpsichord had sixty small coloured glass panes, each with a curtain that opened when a key was struck. A second, improved model of the harpsichord was demonstrated for a small audience in December of 1754. Pressing a key caused a small shaft to open, in turn allowing light to shine through a piece of stained glass Castel thought of color-music as akin to the lost language of paradise, where all men spoke alike, and he claimed that thanks to his instrument's capacity to paint sounds, even a deaf listener could enjoy music.
Item nr. 147167