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).
Table of results for halving resistance with a new box on a 15-volt range.
| Identifier | ExFiles\Box 33\4\ Scan191 | |
| Date | 20th May 1920 | |
| X.1782 20.5.20. X.2067 X.1782. EFC. Halving resistance with new box on 15 volt range. Volts. | Reading. | Constant. ---|---|--- 15.05 | 8.95 | 1680 13.45 | 8.00 | 1680 11.25 | 6.68 | 1682 8.95 | 5.31 | 16.84 6.75 | 4.00 | 1684 4.50 | 2.68 | 1680 2.22 | 1.31 | 1680 L.F. | ||