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).
Data table comparing performance characteristics of various magnetos.
| Identifier | ExFiles\Box 4\5\ 05-page143 | |
| Date | 1st February 1921 guessed | |
| -2- (6) (14) (16) Magneto. Degrees of make. Maker's make advanced. Maker's break advanced. Our make advanced. Our break advanced. Lowest speeds for 5.5 mm. Adv. Cent. Retd. Remarks. Watford. 154.5 -57° 97.5° " 155 -59° 96° " 163.5 -78.5 85° R.{Sir Henry Royce} Bosch. 82.5 11.5 94° U.S.A. Bosch 153 -53.5° 99.5° U.S.A. Bosch 155.5 -79° 76.5 Dixie. Eisemann Conner. R.R. LTD. DERBY. NO. 1478 | ||