Comet Steels of Pontardawe, near Swansea, South Wales
William Gilbertson (1810-1882) of Cwmavon, Glamorgan, was a leading citizen in Pontardawe and the founder of Messrs. William Gilbertson and Company Limited.
1860 Company established.
1862 London Exhibition .
1860s Acquired Primrose Forge and Tinplate Works at Pontardawe.
1900 Faced with increased demand for tinplate and sheet steel, the Gilbertsons decided to increase capacity by building a new steelworks on a site adjacent to Port Talbot Dock, in conjunction with Miss Emily Talbot of Margam who provided a lease on the land. A private company was formed: Port Talbot Iron and Steel Co.
1904 Mr F. W. Gilbertson of F.(sic) W. Gilbertson and Co, steel, tinplate and galvanizing works at Pontardawe, gave evidence to the Tariff Commission.
1910 Galvanizing had taken the place of tinplate manufacture; W. Gilbertson and Co acquired tinplate from Bryanman; installed 6 new tinplate mills
1914 Manufacturers of Siemens steel. Specialities: tinplates, terne plates, aluminium coated plates, galvanized sheets, high carbon and soft steel billets and bars, basic slag meal. Employees 1,600. 
1919 March. Advert for Comet Steels with 2,500 tons produced every week. 
1937 Listed Exhibitor - British Industries Fair. Tinplate, Blackplate, Galvanizing and Sheet Mills. (Stand No. D.328)