Graphometer. The graphometer is in two pieces. Half of the shaped leather case and the tripod mounting cup with articulated joint are NAV1407.1-2 and the other half of the case is marked NAV1407.3 They can be found via the Whole/Part toggle.
Graduations-Semi-circle graduated 0-90-0 and inscribed "OCCIDENT" "SEPTENTRION" "ORIENT" and carries a diagonal scale. The alidade 11" (28cm) long is inscribed with parallel lines. A small suspension lug is attached to upper part of semi-circle and a straight edge 14.3" (36.9cm) long to lower part, inscribed "TABLE DES SINVS" with a table. On reverse of straight edge is inscribed "TABLE FECONDE" "PERPENDICVLARE" "HIPOTEMVSE" with a table. Fitted with a ball and socket head.
Sights-Two sight vanes 1.9" (4.8cm) long, mounted on straight edge, each having a vertical slit. Two sight vanes 1.9" (4.8cm) long, mounted on alidade, each having a vertical slit.
Compass-Dia. 1.6" (4.1cm) mounted at left end of straight edge. Fitted with a blued steel needle 1.25" (3.2cm) long, with a brass pivot cap at centre. Graduated to 32 points.
In shaped case covered with dark red /gold tooled leather and lined with crimson velvet.