Basic steel is now largely made from inferior pig-iron, such as the Cleveland, by the Thomas-Gilchrist process patented in 1878. It is, however, only a modification of the Bessemer process to the extent of substituting for the siliceous or 'acid' lining generally used, a lime or 'basic' lining for the converter. Limestone, preferably a magnesian limestone in some form, is commonly employed for the lining. By the use of a basic lining, phosphorus is eliminated towards the end of the 'blow.' Phosphorus is a very deleterious substance in steel, and is present, sometimes to the extent of 2 per cent., in pig-iron smelted from impure ore.
The four inventions of this century which have given the greatest impetus to the manufacture of iron and steel were--the introduction of the hot blast into the blast-furnace for the production of crude iron, made by J. B. Neilson, of the Glasgow Gas-works, in 1827; the application of the cold blast in the Bessemer converter which we have just described; the production of steel direct from the ore, by Siemens, in the open hearth; and the discovery of a basic lining by which phosphorus is eliminated and all kinds of iron converted into steel. This last was the discovery of G. J. Snelus, of London, and it was made a practical success by the Thomas & Gilchrist process just described. In 1883, Mr Snelus was awarded the Bessemer gold medal of the Iron and Steel Institute 'as the first man who made pure steel from impure iron in a Bessemer converter lined with basic materials.'
Sir Henry Bessemer, the inventor of the modern process of making steel from iron, which has just been described, was the son of Anthony Bessemer, who escaped from France in 1792, and found employment in the English Mint. He was born in 1813, at Charlton, Herts, where his father had an estate, was to a great extent self-taught, and his favourite amusement was in modelling buildings and other objects in clay. He came up to London 'knowing no one, and no one knowing me--a mere cipher in this vast sea of enterprise.' He first earned his living by engraving a large number of elegant and original designs on steel with a diamond point, for patent medicine labels. He found work also as designer and modeller. He has been a prolific inventor, as the volumes issued by the Patent Office show. It has been said that he has paid in patent stamp duties alone as much as £10,000. At twenty he invented a mode of taking copies from antique and modern basso-relievos in such a way that they might be stamped on card-board, thousands being produced at a small cost.