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).
Directive on the frequency and conditions for conducting tests following alterations or at regular intervals.
| Identifier | ExFiles\Box 49\1\ Scan029 | |
| Date | 4th December 1912 guessed | |
| -2- These and all other tests should be made whenever the smallest alterations are made in design, materials or manufacture (principally heat treatment) In addition they should be repeated every 6 months to see if any change has crept in unobserved. F.H.Royce. | ||