BERTHIOT, Lyon, milieu du XIXème siècle Brass ball-jointed graphometer with pinnules and compass. Signed. Length: 22.2 cm. Scratches and minor wear. In a walnut case, numbered 203 and 409 (stains, scratches and dents; slightly off-set lid). Claude François BERTHIOT (1819-1860), mechanical optician, active between 1844 and 1860, at 48 quai des Célestins, Lyon. His widow, Marie GRENIER, continued in business until 1862.