From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Blueprint showing the correct graduation for a gauge marked in Gallons.
| Identifier | ExFiles\Box 175\6\ img005 | |
| Date | 11th February 1929 guessed | |
| E-77064 ALL OTHER DIMENSIONS UNALTERED CORRECT GRADUATION 60° 16° 5° 13° 12° ¾ Gals. 1 Gal. 1¼ Gals. 1½ Gals. AL | ||