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 showing the permeability of pole quality steel.
| Identifier | ExFiles\Box 62\1\ scan0090 | |
| Date | 6th November 1932 guessed | |
| COPY Pole Quality Steel - Permeability. Magnetising force. Induction (lines per sq cm) H.{Arthur M. Hanbury - Head Complaints} B. 3.4 8000 5.3 10300 7.2 11100 10. 11900 15 12900 22 13700 28 14200 50 15359 85 16100 120 17000 | ||