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 detailing observations of spark characteristics for multiple configurations.
| Identifier | ExFiles\Box 63\4\ scan0016 | |
| Date | 26th May 1918 guessed | |
| (16) (73) ZR6/C/150/2/A/A One short sharp, thick, bluish white spark, sometimes two apparent. (74) ZR6/C/150/2/A/B 1 short sharp spark as opposite. (75) ZR6/C/150/2/B/A As above. (76) ZR6/C/150/2/B/B No spark. (77) ZR6/C/150/5/A/A Very occasional single spark as above. Capacity of condenser too great to be charged up to sparking voltages. (78) ZR6/C/150/E/A/B No spark. | ||