probably made in London
Gunner's callipers were used for making shot measure and artillery calculations. These brass callipers were made in the late 18th century, probably by George Adams, a scientific instrument maker based in London.
This side is marked with scales for 'Shot/ Quantity of Powder for ye Chamber of/ Brass Mortars & Howitzers'. Scales at the hinge give diameters in inches (concealed) and the corresponding weight of iron shot.
The callipers consist of two flat brass blades hinged so that they slide freely over each other, allowing the steel tips to point either inwards to indicate take the diameters of shot, or outwards to measure the bore of a gun.
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