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 showing the viscosity curves for various steering box oils.
| Identifier | WestWitteringFiles\Q\2-July1927-September1927\ 69 | |
| Date | 5th July 1927 guessed | |
| VISCOSITY CURVES STEERING BOX OILS OIL TEMPERATURE IN C° TIME OF EFFLUX SECS CURVE LABELS: ISOVIS MOTORINE B MOTORINE C LARD OIL SPERM MOBILE E | ||