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).
Laboratory analysis of two samples of Amber Gear Oil, marked A and B.
| Identifier | ExFiles\Box 144\1\ scan0102 | |
| Date | 17th October 1924 | |
| x967 H11/EA171024 Laboratory Re 2 Samples of Oil marked A & B Amber Gear Oil "A" was found to be a pure mineral oil, and "B" to contain 99.171% mineral oil. H1. | ||