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 recording the results of an electrical test, including average amperes, hours, and ampere-hours.
| Identifier | ExFiles\Box 168b\3\ img187 | |
| Date | 24th February 1929 | |
| 24-2-29 183-4 P&RBDH11-192 107lbs 75 o/s Average amperes - 6.3 Hours : 9.2 Ampere hours - 52.9 494 1.80w | ||