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).
Page stating that Ebonite, or 'Hard rubber', is only used for experimental work.
| Identifier | ExFiles\Box 61b\4\ scan0027 | |
| Date | 15th April 1921 guessed | |
| -2- Contd. Beyond the uses specified above, Ebonite (or 2 "Hard rubber" as it is called here) is not used except for experimental work. | ||