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).
Comparative table of properties for various grades of oil.
| Identifier | ExFiles\Box 145\1\ scan0061 | |
| Date | 1st November 1932 | |
| XIVES GRADE. Spec. Grav. Visc. @ 70°F.{Mr Friese} Visc. @ 140°F.{Mr Friese} Pour test. Closed fl CASTROL "XL" .905 40'00" 4'5" 5°F 430°F CASTROL "XXL" .904 75'0" 7'5" 0°F 420°F MOTORINE "C" (sample taken July) .913 48'20" 3'35" 10/15°F 410°F MOBILOIL "D" (Nov.1932) .911 51'30" 4'10" 25°F 375°F AEROSHELL (August) .919 68'50" 5'38" -5°F 430°F ESSOLUBE 40 (July) .887 42'50" 3'34" -10°F 470°F ESSOLUBE 50 (August) .887 43'10" 4'30" 10°F 485°F | ||