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).
Telegram detailing the location of a test coil and the plan to measure its temperature.
| Identifier | WestWitteringFiles\J\November1922\ Scan36 | |
| Date | 20th November 1922 | |
| Roycar Derby. Clarke test coil located Base two inches above ignition power face centre 4 1/2 inches further out than Power and opposite wheelcase joint endeavour to find Temperature of coil in this and standard royce Position | ||