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 electrical measurements including amperes, ampere-hours, and ohms.
| Identifier | ExFiles\Box 38\5\ Scan369 | |
| Date | 17th April 1923 | |
| P & R BDTH/1/ 74 17 - 4 - 23 Amps per Div = .289 Average amperes = 9.8N Ampert hours = 45.7 Ohms in circuit = 1.17 REGD. TRADE MARK X3398 | ||