Stauroscope

unsigned
Stauroscope for the measurement of extinction angles in crystal sections. Reflecting glass plate polarizer (10.8 x 10.8 cm) on a mahogany base (21 x 13.5 cm); graduated half circle (diameter 9.5 cm) on the lacquered brass body tube (length: 19 cm).
unsigned, but probably Böhm & Wiedemann, München

collection: Museum for the History of Sciences, Universiteit Gent, Belgium (inventory number: MW 93/056-CV)