Die Theorie des Sehens und räumlichen Vorstellens, vom physikalischen, physiologischen und psychologischen Standpunkte
Carl Sebastian Cornelius's 1861 treatise on vision and spatial perception, published in Halle by Schmidt for German readers in physics, physiology and psychology. The 117 wood-engraved figures are line diagrams: ray bundles converging through lenses, cross-sections of the eyeball with labelled focal points, and geometric constructions on plane grids, usable as sparse technical linework.
