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).
Test results comparing the performance of different brands of grease.
| Identifier | ExFiles\Box 145\1\ scan0019 | |
| Date | 25th May 1933 guessed | |
| Of all brands of greese tested the R.R type proved to be the best. Types tested Mobilgrease No 6. 75% used on 10hr run. Wakefield's White Compound. 90% " " " " RR 50% " " " " | ||