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).
Conversion table with corresponding values for 'H' and 'h' based on logarithmic formulas.
| Identifier | ExFiles\Box 77\5\ scan0149 | |
| Date | 26th April 1917 guessed | |
| Log H = 1.1868 + h/10 h = 10 log H - 11.868 H.{Arthur M. Hanbury - Head Complaints} h.{Arthur M. Hanbury - Head Complaints} H.{Arthur M. Hanbury - Head Complaints} h.{Arthur M. Hanbury - Head Complaints} 15 -.11 90 7.67 16 +.17 92.5 7.79 17 .43 95 7.91 18 .68 97.5 8.02 19 .92 100 8.13 20 1.14 105 8.34 21 1.35 110 8.54 22 1.55 115 8.74 23 1.75 120 8.92 24 1.93 125 9.10 25 2.11 130 9.27 26 2.28 135 9.43 27 2.44 140 9.59 28 2.60 145 9.74 29 2.75 150 9.89 30 2.90 160 10.17 31 3.04 165 10.31 32 3.18 170 10.43 33 3.31 175 10.56 34 3.44 180 10.68 35 3.57 185 10.80 36 3.69 190 10.92 37 3.81 195 11.03 38 3.93 200 11.14 39 4.04 205 --- 40 4.15 210 11.35 42 4.36 215 ===11.55== 44 4.57 220 11.55 46 4.76 230 11.75 48 4.94 240 11.93 50 5.12 250 12.11 52.5 5.33 260 12.28 55 5.53 270 12.44 57.5 5.73 280 12.60 60 5.91 290 12.75 62.5 6.09 300 12.90 65 6.26 310 13.04 67.5 6.42 315 12.11 70 6.58 320 13.18 72.5 6.73 325 13.25 75 6.88 330 13.32 77.5 7.02 335 13.38 80 7.16 340 13.45 82.5 7.29 345 13.51 85 7.42 350 13.57 87.5 7.55 | ||