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).
Comparing the actual capacity of thermostat and standard type 20 HP radiators.
| Identifier | ExFiles\Box 77\4\ scan0348 | |
| Date | 1st April 1924 | |
| X4240 Mr. Hives from THM. 1.4.24. 20 HP. RADIATOR. Actual capacity of thermostat type = 21.75 pts. Actual capacity of standard type = 23.25 pts. Hs{Lord Ernest Hives - Chair}/THM. | ||