Bericht über Liesegangs Universal-Projektions-Apparat
A German trade catalogue and manual issued by Ed. Liesegang of Düsseldorf in 1913, describing the firm's universal projection apparatus for teachers, lecturers and laboratory demonstrators. Halftone photographs show lantern housings, bellows, condensers and polarising attachments mounted on optical benches, with dotted lines tracing light paths — useful for silhouettes of scientific instruments and diagrammatic ray overlays.
