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).
Test results for the melting point of 73°C coil and condenser sentinels.
| Identifier | ExFiles\Box 45\4\ Scan188 | |
| Date | 16th August 1923 | |
| X4079 EFC. 16.8.23. X.4079 X.4430. RE MELTING POINT OF SENTINELS. The results of the melting points of the 73°C coil and condenser sentinels are 73°C. One sentinel was taken for test in each case. GJ. | ||