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).
Test results for an A.T. Speedometer, recording MPH and revolutions per mile at different temperatures.
| Identifier | ExFiles\Box 50\4\ Scan185 | |
| Date | 20th March 1928 | |
| X4308 20.3.28. A.T. SPEEDOMETER A.929. N.730. 15/52. Temp. M.P.H. at 600 R.P.M. Revs/Mile. 16.8 50.2 717 22.0 49.1 734 24.5 48.6 740. 30.1 47.5 758 EFC. {E. Fowler Clarke - Electrical Engineer} Returned to production after test. | ||