Contact goniometer hinged at the 90° graduation

 

Richer à Paris
Contact goniometer hinged at the 90° graduation (silver and steel, outside diameter 8 cm) in green plush-lined and leather-covered case (12.7 cm wide).
Signed "Richer à Paris", first half 19th century.

private collection

Contact goniometer hinged at the 90° graduation,  Richer à Paris