1911 Encyclopædia Britannica/Thomas, Sidney Gilchrist

THOMAS, SIDNEY GILCHRIST (1850–1885), British inventor, was born on the 16th of April 1850 at Canonbury, London. His father, a Welshman, was in the civil service, and his mother was the daughter of the Rev. James Gilchrist. His father’s death leaving his family with a considerably reduced income, he gave up his original idea of becoming a doctor and obtained an appointment as a police court clerk, which he held till May 1879. During these twelve years, besides the work of a busy police court, which brought him into intimate contact with social problems, he found time to study chemistry, and attended lectures at the Birkbeck Institute. He set himself to solve the problem of eliminating phosphorus from iron by means of the Bessemer converter, and by the end of 1875 was convinced that he had discovered a method. He communicated his theory to his cousin, P. C. Gilchrist, who was chemist to iron works in Wales, and experiments were made, which proved satisfactory. Edward Martin, manager of the Blaenavon Works, gave facilities for conducting the experiments on a larger scale and undertook to help in taking out a patent. In March 1878, the first public announcement of the discovery was made at the meeting of the Iron and Steel Institute, but without attracting much attention; and in September a paper was written by Thomas and Gilchrist on the “Elimination of Phosphorus in the Bessemer Converter” for the autumn meeting of this institute, but was not read till May 1879. Thomas, however, made the acquaintance of E. W. 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. The “basic process” invented by Thomas was especially valuable on the continent of Europe, where the proportion of phosphoric iron is much larger than in England, and both in Belgium and in Germany the name of the inventor became more widely known than in his own country. In America, although non-phosphoric iron largely predominates, an immense interest was taken in the invention. But Thomas had been overworking for years, and his lungs became affected. A long sea voyage and a residence in Egypt proved unavailing to restore his health and he died in Paris on the 1st of February 1885. He had what W. E. Gladstone, in a review of the Memoirs published in 1891, described as an “enthusiasm of humanity,” and he left his fortune to be used for the promotion of philanthropic work. A police court mission was endowed in his memory.

See Memoirs and Letters of Sidney Gilchrist Thomas (1891), ed. by R. W. Burnie.