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).
Electrical experimental record sheet for a 20/25 Switchbox.
| Identifier | ExFiles\Box 166\8\ img010 | |
| Date | 24th November 1931 | |
| X. No. X6067 Item No. ELECTRICAL EXPERIMENTAL RECORD SHEET. Description of item :- 20/25 Switchbox - T-R S+T cum first. 2J resistance Date on | Location | REMARKS | Miles reading start | Miles Covered. | Total Miles. 29-6-31 | 19 G | Put on 19 G for 10,000 miles test, with 2J resistance. | 489 | - | - 24-11-31 | " | No complaints. Quite O.K. throughout run. C.A.P. 24-11-31 | 20,204 | 19,715 | 19,715 | ||