Cazenave (Fréderic) L'Optique, or "The Optical Viewer", after Louis Léopold Boilly, etching and engraving with stipple, a good early impression with little wear to the plate, sheet 535 x 435 mm (21 x 17 in), under glass, presumably trimmed to image without lettered margin, minor surface dirt, framed, [circa 1794]; together with an original Zograscope, a device for looking at Vues d'Optique, wood, glass, reflective mirror, the spindle broken, [late 18th or early 19th century] (2)*** The Zograscope, as shown in the engraving after Boilly's painting of Louise Gély, is an optical viewer for prints, where the print is laid flat on the table and reflected in an angled mirror and observed through a vertical lens.