ESOTERIC ART - HEIDELBERG An engraving from Robert Fludd's Utriusque Cosmi Maioris: Tractatus Secundus, 1618, depiting an device designed to aid painters or draghtsmen attain accurate rendering of views. The eye is fixed at a single point, and the artist looks through a grid, into which he draws the scene beyond. It has been suggested by Yates that the castle on the horizon is Heidelberg, the main centre of the Rosicrucian enlightenment, in Europe.