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).
Test report detailing spark and arc behavior under various conditions and configurations.
| Identifier | ExFiles\Box 63\4\ scan0005 | |
| Date | 26th May 1918 guessed | |
| 5. (7) ZRG/150/5/R/A No spark. At decreased gap (4mm) single spark appears. On still further decreasing gap arc appears. (8) ZRG/150/5/R/B Single spark no arc. (9) ZRG/150/7/A/A No spark. (10) ZRG/150/7/A/B No spark. 646 (11) ZRG/150/7/R/A No spark. (12) ZRG/150/7/R/B No spark. | ||