Traité de la lvmiere, où sont expliquées les causes de ce qui luy arrive dans la reflexion, & dans la refraction. Et particulierement dans l'etrange refraction dv cristal d'Islande
Christiaan Huygens's Traité de la lumière, printed in French by Pieter van der Aa at Leiden in 1690, sets out his wave account of reflection, refraction and the double refraction of Iceland crystal for mathematicians and natural philosophers. The plates are letterpress-scale geometric diagrams in plain line: circles crossed by tangents and chords, lettered points, expanding wavefronts and rhomboid crystal blocks, useful as spare diagrammatic line art.
