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).
Two negative prints of oscillograph traces comparing different levels of vibration.
| Identifier | ExFiles\Box 25\3\ Scan102 | |
| Date | 16th April 1923 guessed | |
| [Illegible text on film strip] | ||