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).
Experimental record sheet for Tungsten contact points.
| Identifier | ExFiles\Box 35\6\ scan 348 | |
| Date | 19th April 1926 | |
| X2894 ELECTRICAL EXPERIMENTAL RECORD SHEETS X. No:- 2894 Tungsten contact points. Date on. | Location. | Date off. | REMARKS. | Miles reading start. | Miles reading finish. | Miles covered. | Total miles. 24-3-27 | 12 EX | | Fitted to 12EX. | 4761 | | | 2-5-27 | " | | | | 5382 | 621 | 621 8-6-27 | " | | Trimmed and reset | | 8105 | 2723 | 3344 7-7-27 | " | | Speedometer changed. | | 9993 | 1888 | 5232 15-7-27 | | | | 1227 | 0005 | 12 | 5244 26-8-27 | " | | Condition V.{VIENNA} Fair bedding 30%. | | 3234 | 2007 | 7251 5-10-27 | " | | | | 4656 | 1422 | 8673 1-11-27 | " | | trimmed and reset | | 6015 | 1359 | 10032 10-11-27 | " | 10-11-27 | Points removed. Condition Fair. Wear - practically nil. | | 6824 | 809 | 10,841 19.4.26. | ||