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).
Letter from The Igna Engineering Co. Ltd. describing their patent cleaner and ruby mica sparking plugs.
| Identifier | ExFiles\Box 33\3\ Scan018 | |
| Date | 11th October 1919 | |
| Messrs. Rolls-Royce Ltd., (Contd) any kinds and by means of the "IGNA" Patent Cleaner, of which we shall also be pleased to send you a sample, it is possible to clean the Plug in 5 seconds when it has been accidentally oiled up as sometimes does happen. This is impossible in other Plugs and represents the ideal form of Sparking Plug as when a Plug is taken apart to clean it is never re-assembled in the proper manner and many times when this is done with a Porcelain Plug it is attended by either breaking or cracking of the Porcelain. The Insulation being pure Ruby Mica without "dope" of any kind is unaffected by any degree of heat and the Plug will run satisfactorily in Engines having as high a Compression as 120 lbs per square inch. We shall be most pleased to receive your valued orders which shall have our very best attention. Yours faithfully, per pro THE IGNA ENGINEERING CO. LTD., JCWells Managing Director BN.{W.O. Bentley / Mr Barrington} 11 OCT 1919 RECEIVED | ||