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).
Graph chart recording an electrical performance test over a period of 9 hours.
| Identifier | ExFiles\Box 38\5\ Scan371 | |
| Date | 13th February 1924 | |
| 75. P&RBDII-2 13-2-24 95lb 75 a.h. 9.0 hours Average amperes = 6.36 Ampere hours = 57.2 .60 1.80w REGD: TRADE MARK 'MEGGER' | ||