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).
List of single variations from standard for tungsten contact point experiments.
| Identifier | ExFiles\Box 61b\1\ scan0121 | |
| Date | 9th October 1930 | |
| -K- 9.10.30. TUNGSTEN CONTACT POINT EXPERIMENTS. SINGLE VARIATIONS FROM STANDARD. (1) Reversal of current supply. (2) Stronger spring. (3) Platinum screw point. (4) Platinum lever point. (5) Domed screw point. (6) Three,flat cam (7) Offset lever. (8) Remy with stiffened arm. (9) Low value condenser. | ||