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).
Lookup table of values for 'P' and 'Z' based on two logarithmic formulas.
| Identifier | ExFiles\Box 77\5\ scan0147 | |
| Date | 26th April 1917 guessed | |
| Log P = 1.7000 + Z / 40 Z = 40 log P - 68 P Z P Z 50 -.04 70 5.80 50.5 .13 70.5 5.93 51 .30 71 6.05 51.5 .47 71.5 6.17 52 .64 72 6.29 52.5 .81 * 72.5 6.41 53 .97 73 6.53 53.5 1.14 73.5 6.65 54 1.30 74 6.77 54.5 1.46 74.5 6.89 55 1.62 75 7.00 55.5 1.77 75.5 7.12 56 1.93 76 7.23 56.5 2.08 76.5 7.35 57 2.25 77 7.46 57.5 2.39 77.5 7.57 58 2.54 78 7.68 58.5 2.69 78.5 7.80 59 2.84 79 7.90 59.5 2.98 79.5 8.02 60 3.13 80 8.12 60.5 3.27 80.5 8.23 61 3.41 81 8.34 61.5 3.56 81.5 8.45 62 3.70 82 8.55 62.5 3.84 82.5 8.66 63 3.97 83 8.76 63.5 4.11 83.5 8.87 64 4.25 84 8.97 64.5 4.38 84.5 9.08 65 4.52 85 9.18 65.5 4.65 85.5 9.28 66 4.78 86 9.38 66.5 4.91 86.5 9.48 67 5.04 87 9.58 67.5 5.17 87.5 9.68 68 5.30 88 9.78 68.5 5.43 88.5 9.88 69 5.55 89 9.98 69.5 5.68 89.5 10.07 | ||