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).
Data table for converting speed readings between a proportional scale and a new contract scale.
| Identifier | ExFiles\Box 59\2\ Scan130 | |
| Date | 23th March 1931 guessed | |
| -10- d₀ Original reading in miles per hour on proportional scale. .0006 d₀² d divisional position on the old propor- tional scale at which the division corresponding to d₀ miles per hour on the new contract scale should be placed. 0 0 0 5 .015 4.985 10 .060 9.940 15 .135 14.865 20 .240 19.760 25 .375 24.625 30 .540 29.460 35 .735 34.265 40 .960 39.040 45 1.215 43.785 50 1.50 48.50 55 1.82 53.28 60 2.16 57.84 65 2.53 62.47 70 2.94 67.06 75 3.37 71.63 80 3.84 76.16 85 4.33 80.67 90 4.86 85.14 | ||