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).
Page 2 of a document describing a duplex outgoing filter system with a 2-gallon reserve.
| Identifier | WestWitteringFiles\N\2July1925-September1925\ Scan107 | |
| Date | 29th September 1925 guessed | |
| (2) and water, and very large duplex outgoing filters, which are arranged for a 2 gallon reserve, and can in a moment be changed over if one of the 30 sq. in. area filters are blocked. R.{Sir Henry Royce} | ||