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).
Describing a cross-section through a scored mark.
| Identifier | ExFiles\Box 127\3\ scan0128 | |
| Date | 1st October 1935 guessed | |
| M1193. A1493-7 A1500. Cross. section through scored mark. | ||