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).
General magneto specification document featuring two performance curves.
| Identifier | ExFiles\Box 37\1\ scan 295 | |
| Date | 13th September 1924 guessed | |
| General Magneto Specification X3949 | ||