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 graph with data plotted on a grid with a numbered horizontal axis.
| Identifier | ExFiles\Box 181\M7\ img074 | |
| Date | 1st May 1923 | |
| 2250, 2500, 2750, 3000. Stamped text: ROLLS-[illegible] LIMITED, [illegible] ROOM., 1 MAY. 23 | ||