Prolonged painstaking observation enabled him to draw the internationally acclaimed Seyler Coal Chart from which information about volatile matter and calorific values could readily be extracted. For this highly specialised work the South Wales Institute of Engineers awarded him its Gold Medal in 1931 and in 1937 the Bar to it. In 1941 he was awarded the Melchett Gold Medal of the Institute of Fuel.
After much heart searching he left Swansea, the true town of his adoption over a period of 50 unbroken years, at the end of 1942, in order to become General Consultant to the British Coal Utilisation Research Association and head of its Coal Systematics and Petrology Dept. He served in both capacities until 1957 and his reputation internationally was evidenced by his election in 1955 as the first president of the International Committee for Coal Petrology. Retiring in 1957, he remained an Honorary Consultant to B.C.U.R.A. until his death.
His publications include: introduction to Greenwell and Elsden, Analysis of British coal and coke (1907); Classification of Coal (World Engineering Congress, Tokyo, 1929); Petrography and the Classification of Coal, I, II (1931, 1937); Fuel technology (1931); Description of Seyler's Fuel Chart (1933); Selection of coals for steam raising (1934); Recent progress in petrology of coal (Melchett Lecture, 1941); Die Entwicklung der Kohlen-Petrographia (1951); with W.H. Edwards, The microscopical examination of coal (1929); with Illingworth and Wheeler, Report on explosions in anthracite stoves (1924); and papers in the Trans. of the South Wales Institute of Engineers, and the Royal Society.
For his ‘dilettante enjoyments’, as he called them, after long weeks of laboratory work, he would apply his clear mind to difficult questions about the history of Swansea and Gower and offer lucid explanations of local place-names, in lectures to the Royal Institution of South Wales, Swansea, or in articles in Arch. Camb., e.g. ‘Early charters of Swansea and Gower’ (1924, 1925); ‘Stedworlango: the fee of Penmaen in Gower’; (1920); ‘Seinhenyd, Ystumllwynarth and Ynysgynwraid: some place-names and folk-lore in Wales’ (1950).
He was president of Swansea Rotary Club, 1929-30, of the South Wales Institute of Engineers, 1931-32, of the Royal Institution of South Wales, 1932-33, and a member of the Council of the National Museum, of the Cambrian Archaeological Association and of Surrey Archaeological Soc. He was B.Sc. (London) and was awarded an hon D.Sc. (Wales) in 1938. He was also F.R.I.C.
He m. Ellen Andrews in 1895 and they had 2 dau. Athène Seyler, C.B.E., the actress who died in 1990 aged 101, was his sister. C.A. Seyler died at his home, Gaywood, Chine Walk, Ferndown, Dorset, 24 July, 1959.
William Cyril Rogers, (1911-95), Swansea