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).
Letter concluding that core hardness measurements from 500 to 600 diamond hardness are thoroughly chaotic.
| Identifier | ExFiles\Box 153\1\ scan0224 | |
| Date | 30th March 1939 | |
| -2- Rm{William Robotham - Chief Engineer}/FJH.{Fred J. Hardy - Chief Dev. Engineer}15/JH. 30th. March.1939. Core hardnesses we have so far measured range from 500 to 600 diamond hardness. You will see from the above that the whole position appears to be thoroughly chaotic. Yours faithfully, FOR ROLLS-ROYCE LTD. | ||