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).
Diagrammatic analysis of different types of sparks and their characteristics.
| Identifier | ExFiles\Box 63\4\ scan0018 | |
| Date | 26th May 1918 guessed | |
| (18) (85) ZR6/C/600/2/A/A Short sharp bluish white sparks Tiny red sparks fly of disintegrated material. (86) ZR6/C/600/2/A/B Single or two short, sharp sparks. (87) ZR6/C/600/2/B/A Short sharp sparks Long straggling sparks of diminishing intensity towards point. (88) ZR6/C/600/2/B/B Several short sharp sparks (probably representing oscillations). (89) ZR6/C/600/5/A/A Single sharp spark only. Missing. (90) ZR6/C/600/5/A/B No spark. | ||