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).
Diagram and explanation of the path of platinum points within a circular component.
| Identifier | ExFiles\Box 36\1\ scan 115 | |
| Date | 30th June 1917 guessed | |
| 17/ Z i.e. practically a straight line path after the first fling off. This straight line path implies a drawing together of the platinum points and continues until contact is made. at position 2. | ||