His father's death left the family with a considerably reduced income, so Thomas gave up his original idea of becoming a doctor and obtained an appointment as a police court clerk, which he kept until May 1879.

George Chaloner, the chemistry teacher at the Institute, remarked one evening that "the man who eliminates phosphorus by means of the Bessemer converter will make his fortune."

Thomas, however, made the acquaintance of Edward Windsor Richards, the manager of Bolckow Vaughan & Co's works at Cleveland, Yorkshire, whom he interested in the process, and from this time the success of the invention was assured and domestic and foreign patents were taken out.

[8] In 1883, jointly with George James Snelus, who had previously discovered the process but had failed to develop it, he was awarded the Bessemer Gold Medal of the Iron and Steel Institute for their work on dephosphorisation.

In July 1960 an obelisk dedicated to his memory was erected in South Wales by the Newport and District Metallurgical Society in conjunction with the Iron and Steel Institute.