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).
Chart recording from an electrical test showing amperage over time, with calculated results.
| Identifier | ExFiles\Box 54\1\ Scan251 | |
| Date | 6th May 1927 | |
| 6-5-27, 156, S3, 75a.h., 103 lbs., Average amperes = 6.31, Hours = 9.2, Ampere hours = 58.0, .563, 1.80w., TRADE MARK 'MEGGER' | ||