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).
Laboratory memo regarding the unsatisfactory chemical colouring of three miniature switches.
| Identifier | ExFiles\Box 38\3\ Scan244 | |
| Date | 26th March 1920 | |
| X.3362 EFC. Laboratory. H17/EB26.3.20. X.3362 - LIGHTING INSTALLATION AT W.W. We are returning the three miniature switches which you sent for treating. One of these has only had the cover done and is a mauvish black colour. The handle has been left and we did not take the switch to pieces for the purpose of treating it as well, since it is possible that we should not refit it correctly. We can do this, however, if you do not mind taking the risk, and we should then seal up with paraffin wax. An attempt has been made at producing a darker tone with the other two, but the result is not very satisfactory, nor is the effort at colouring the knobs without disconnecting them. We are trying different proportions of the substances used for attaining the chemical coat, as the result we anticipate that we shall be able to get a darker colour in future if you desire it. Should you like the three small switches redone we will deal with the matter at once on return of same. HCH. They should last better if lacquered or varnished. | ||