Engraved brass plate, originally proposed by Gould in September 1921, and engraved and fitted to he backplate of H1 after the completion of the first cleaning of the timekeeper at the end of that year. The engraving is filled with black and red engravers wax. The plate was removed during the 1931-33 restoration and fitted to the present mahogany sloping block, to be exhibited alongside the timekeeper when on display in the Science Museum and subsequently in the NMM. The block with samples of the corrosion from the timekeeper (see ZAA0862) was also displayed in this way and was designed as a pair to this one.