Folding Stereoviewers (various)

collection of three early folding Brewster viewers in embossed linen or leather, all in very good condition, (1) large viewer of black cloth with square lenses, folds into a linen covered wooden box, (2) smaller viewer of a similar construction with round lenses, covered in of grey cloth, (3) very elegant scope made of embossed oxblood leather with two flat circular lenses, folds into a slim sheath. These kind of folding viewers were very popular especially in France and England around 1860 - very hard to find in such good condition. (3)