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 comparing the horsepower curves of various car models.
| Identifier | ExFiles\Box 180\M4\M4.2\ img026 | |
| Date | 25th February 1923 guessed | |
| HORS 30 20 MARMON CAR. - H.P. CURVE. 10 BUICK CAR. - H.P. CURVE. HUMBER CAR. - H.P. CURVE. DODGE CAR. - H.P. CURVE. HUP CAR. - H.P. CURVE. 0 500 750 | ||