A Military Gunter's Rule, With Indian Navy Connection

English, c.1855, engraved 'Elliot Bros, London', and engraved with a military Arrow with an I for India, complete with a second steel rule of similar dimensions but unmarked except for an identical I, scales on both sides of the brass rule, in addition to usual navigation, trigonometric and calculating scales, and scale rule, there are gunner's scales for 'Diameter of Guns', & 'Shot' for various mortars and guns, in the original fitted mahogany case 65.5cm long

Note: the edges to the brass Gunter rule are heavily dinged and dented