A rather ornate black painted wooden base of several tiers supports a screw that can clamp down on an object to determine its thickness. The screw is turned by a large handle with a pointer that moves over a set of paper scales. These could probably have once been turned independently. One is calibrated linearly from 0 to 100, and the others differently and non-linearly from 0 to 36. The whole is on a circular base that would have been covered by a glass dome. An associated card from a Miss Griffiths dated 18.4.46 reads ‘This instrument belonged to Mr Edward Gilbert Senior (1810-1881) of Bath Row, Birmingham and was used in the early days of silver electroplating.’