Operating temperatures for the 25EX Thermostat.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan040 | |
| Date | 21th October 1930 | |
| 25EX Thermostat STARTS TO OPEN @ 50° FULLY OPEN @ 61° STARTS TO CLOSE @ 58° FULLY CLOSED. @ 48° Gard Lyman. 21-10-30 | ||
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).