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 of a line graph plotting data on a grid with numerical axes.
| Identifier | Morton\M4.2\ img029 | |
| Date | 19th May 1921 | |
| M.{Mr Moon / Mr Moore} 40 30 20 10 2000 2250 ROLLS-ROYCE, LIMITED PRINT ROOM. 20 MAY 1921 DERBY 19. 5. 21. | ||