of Permutit House, Gunnersbury Avenue, London, W4. Telephone: Chiswick 6431 (10 lines). Cables: "Permutit, Chisk, London"
1899 Company founded
1911 Water Softeners Ltd Incorporated - sole proprietors of Permutit base exchange medium.
1923 Company made public.
1937 Name changed to Permutit Co
1946 Water Softener made by Permutit Co. Shown at the Britain Can Make It exhibition. 
1947 British Industries Fair Advert for Ion exchange materials - "Zeo-Karb", "De-Acidite". For Recovery of Valuable Minerals, Removal of Impurities, Catalysts, Separation of Poly-Valent Ions from Non-Valent Ions - Demineralisation of Water. (Chemicals etc. Section). 
1961 Manufacturers of water-treatment equipment. 839 employees.