Bessemer process

...steel has been formed it is poured out into ladles and then transferred into molds and the lighter slag is left behind. The conversion process (called the "blow") was completed in around twenty minutes. During this period the progress of the oxidation of the impurities is judged by the appearance of the flame issuing from the mouth of the converter; the modern use of photoelectric[?] methods of recording the characteristics of the flame has greatly aided the blower in controlling the final quality of the product. After the blow, the liquid metal is recarburized[?] to the desired point and other alloying materials are added, dependent on the desired product.

Before the Bessemer process steel was manufactured by heating bars of wrought iron together with charcoal. The bars were then broken into pieces and melted in small crucibles containing 20kg or so. Such steel when rolled into bars was sold at £50 to £60 a ton. The earliest Bessemer converters produced steel for £7 a ton, although they priced it initially at around £40 a ton.