Six inch brass gunners callipers, c 1770.

Image number: 10302788

Six inch brass gunners callipers, c 1770.

These callipers were used for measuring the diameter of cannon balls, or by crossing the arms, the bore of a cannon. They were made by Henry Gregory (fl 1750-1792), mathematical and navigational instrument maker.

Image number:
10302788
Credit:
Science Museum/Science & Society Picture Library
Date taken:
20 October 2003 13:36
Image rights:
Science Museum