Gunner's Protractor

[fernando]

Guys, the person in question is William Deane (first half 18th century) ... and apparently not from the Deane & Dean gun traders family.
He was an expert in precision devices, like gunner's calipers and other.
The following id the description of a device of one of those:

A brass pair of William Deane gunner's callipers, English, first half 18th century, signed William Deane Fecit, the callipers with inset steel points slide over each other to allow both internal and external measurements to be taken, the upper face with geometrical shapes, scales of quantity measures, proof and service, and sector scales 0-100 the reverse with scales for 'cubic feet of metal &c in pounds and Decimals Adverdupois & Inches of ye same in Ounces and Decimals 12inch linear scale, size and weight of guns scale. The hinge with direct reading scales for the width of the opening in inches and degrees together with a 19th century 6-inch ivory yellowed sector., length closed 15.2cm 6in