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).
Visual and descriptive log of different electrical spark characteristics.
| Identifier | ExFiles\Box 63\4\ scan0021 | |
| Date | 26th May 1918 guessed | |
| (21) (103) ZR6/C/2000/5/R/A Sparks and pseudo - arc. slight bushiness to arc. (104) ZR6/C/2000/5/R/B Spark & straggly. sparks. (105) ZR6/C/2000/7/A/A No spark (106) ZR6/C/2000/7/A/B Thick and thin spark. (107) ZR6/C/2000/7/R/A Single or two sparks Missing. (108) ZR6/C/2000/7/R/B No spark. | ||