This is a 19th century monocle made of concave glass with brass frame and gallery. Galleries are designed to help secure the monocle in place by raising it out of the eye orbit slightly. The delicate chain is connected to the monocle by a ring. At the end of the chain is an ear mount. Diopter is -5.0 The monocle is in a hexagonal leather covered case with brown felt lining. Provenance: Viennese collector.