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 with handwritten calculations from an electrical test.
| Identifier | ExFiles\Box 38\5\ Scan370 | |
| Date | 28th May 1923 | |
| P&R BD{Mr Berend}11-2 28-5-23 75 Average amps = 9.73 Amps per Div = .289 Ampere hours = 56.75 Ohms in circuit = 1.17ω 9/32. X3348 REGD. TRADE MARK MEGGER | ||