The English Iron Industry
Iron, as a producer goods industry, needs special treatment; proper coverage requires that one looks at the uses to which iron was put. This is especially important because the output of the eighteenth-century iron industry went for quite different uses than those associated with the modern iron industry. This chapter will begin with a brief overview of the iron industry and those trades closely allied with it. A pictorial description of the iron and allied trades is provided on the following page. To avoid clutter, the various other raw materials required for these processes of production are listed at the bottom of that diagram.
The first operation is the smelting of iron ore to produce pig iron. This act was performed in a furnace using either charcoal or coal as a fuel, and with the addition of a flux such as limestone to draw some of the impurities from the ore. From the furnace, pig iron could be used for two purposes. It could in molten form be cast to produce a variety of cast-iron goods. More commonly, it was taken to a forge where it was converted to wrought iron and formed into bars. Pig iron (or cast iron) has a carbon content of four per cent while wrought iron has virtually no carbon content. A low carbon content makes iron very malleable and thus capable of being hammered into different shapes. However, low carbon content makes it difficult for the final good to keep an edge. Therefore, for cutting tools, steel, which has a two per cent carbon content, was preferred. One might think that steel would be made by drawing off half the carbon from pig iron, but the technology of the day required that steel be created by adding carbon to wrought iron. Due to the expense of steel making, edge tools were generally made with a thin strip of steel attached to an iron body.
In what follows, I will treat the operations of furnace and forge as being the iron industry. Everything else that uses pig or wrought iron