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).
Instructions regarding the acceptable swing of a needle at various speeds.
| Identifier | ExFiles\Box 166\2\ img072 | |
| Date | 5th March 1937 guessed | |
| 6. swing of the needle estimated, as far as possible, at the various speeds. The needle at no time should swing over more than two divisions. Wst. | ||