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).
Diagram of an accelerometer and gradient meter scale.
| Identifier | ExFiles\Box 53\1\ Scan184 | |
| Date | 21th April 1926 guessed | |
| Wood Base Say 6 1/2 x 5 1/2 approx. ACCELERATION FEET PER SEC. PER SEC 8 7 6 5 4 3 2 1 0 RETARDATION LBS PER TON OF 2240 LBS 100 200 300 400 500 UPWARD GRADIENT 1 in 5 1 in 10 15 20 25 50 DOWNWARD GRADIENT 1 in 50 25 20 15 1 in 10 1 in 5 | ||