Advertisement for the SEI Exposure Photometer.
| Identifier | ExFiles\Box 168a\3\ img519 | |
| Date | 1st May 1950 guessed | |
| SEI Exposure Photometer | ||
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).