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 plotting load versus temperature from various thermostat tests.
| Identifier | ExFiles\Box 39\4\ Scan115 | |
| Date | 1st April 1930 | |
| THERMOSTAT TESTS. LOAD - LB- TEMPERATURE °C. SMITH'S ZERO POSITION . .162 ABOVE ZERO Δ .325 " " o .390 " " x SYLPHON ZERO POSITION . .162 ABOVE ZERO Δ .325 " " o 1.080 " " x ETHER ZERO E | ||