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 page logging spark observations for various components.
| Identifier | ExFiles\Box 63\4\ scan0011 | |
| Date | 26th May 1918 guessed | |
| (11) (43) RA2/200/5/R/A Occasional single spark. (no arc) (44) RA2/200/5/R/B No spark. (45) RA2/200/7/A/A No spark. (46) RA2/200/7/A/B No spark. (47) ZA2/200/7/R/A No spark. (48) ZA2/200/7/R/B No spark. | ||