Cardboard Miniature Stereoscopes (various)

very nice collection of seven viewers made of cardboard, (1) French ‘Stéréo Lilliput’ viewer, cardboard box covered in red faux leather, in near mint condition, original box and a set of five extremely rare 'academic studies' slides, showing undressed models in a studio, (2) 'Stéréo-Mondain' viewer concealed in a box in good used condition, comes together with nine original cards, (3) collapsible advertising stereoscope made for the Norddeutscher Lloyd Bremen in perfect condition, (4) small advertising stereoscope for Fritz Homann embossed 'Grösste Deutsche Magarine Werk' in good original condition, (5) 'Perfect-Stéreo' viewer with sliding box focus, rear ground glass is missing, in used condition, (6) unlabeled viewer cover with red linen, ground glass missing, in used condition, (7) 'Phantom Camera' optical toy from 1895, covered with red faux leather, in good condition. (7)