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).
Graph comparing the viscosity curves of different steering box oils at various temperatures.
| Identifier | ExFiles\Box 32\4\ Scan265 | |
| Date | 29th August 1927 guessed | |
| Viscosity Curves STEERING Box Oils OIL TEMPERATURE IN C° TIME OF EFFLUX SECS Isovis Motorine B Motorine C Lard Oil Sperm Mobile E | ||