Ocular goniometer

Negretti & Zambra, London
Ocular goniometer (nickel plated brass), with engraved scale and vernier read-out, ocular and cross wires (height 10.2 cm). In blue plush-lined leather-covered case (width 11.5 cm, height 10 cm).
Unsigned but with an etiquette on the inside of the cover that states "NEGRETTI & ZAMBRA | 122, REGENT ST. | LONDON.W.I.", last quarter of 19th century.

private collection