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).
Log sheet detailing the results of various spark tests, with accompanying waveform diagrams.
| Identifier | ExFiles\Box 63\4\ scan0015 | |
| Date | 26th May 1918 guessed | |
| (1D) (67) ZA2/2000/5/B/A Ditto (68) ZA2/2000/5/B/B Spark & more arc than for advance. (69) ZA2/2000/7/A/A Same as for 600/7 o difference between A & B (70) ZA2/2000/7/A/B No spark. (71) ZA2/2000/7/B/A Ditto. (72) ZA2/2000/7/B/B Single spark only. | ||