Cover of a document titled 'Spark Plug Logic', featuring an illustration of a spark plug.
| Identifier | ExFiles\Box 33\3\ Scan158 | |
| Date | 9th September 1921 guessed | |
| X1812 C Spark Plug Logic | ||
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).