Dating british patent numbers
This confirmed that a design had been registered and gave three year’s copyright protection.
The diamond contained enough information to allow identification from the official records held by the Patent Office.
By shifting the positions of the identifiers, a second series was started and lasted until 1883.
Other letters identified the day and month of registration, the material and bundle number. Small extracts can be used with acknowledgements to 'Oldcopper.org' website. Diamond Registration Marks (Lozenge Marks) Key to Diamond Registration Marks Design Registration Numbers Country of Origin Purchase Tax.