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 report on various A.T. Speedometer models fitted to experimental cars.
| Identifier | ExFiles\Box 50\4\ Scan295 | |
| Date | 1st May 1929 | |
| X4308. 5/29 A.T. SPEEDOMETERS Large dial speedometer No.728 for change of reading test covered 9,320 miles on 14-EX. B563 800 14/52 small type dial on 22-EX. B919 742 15/52 small type dial on 12-EX. | ||