Many English place names are rooted in a vanished industry, the area at the western end of the village known as Cinder Hill almost certainly gets its name from the accumulations of cinder, which were a by-product of the early iron industry that flourished in the Weald of Kent and Sussex for some two thousand years. The area had all the ingredients for the iron smelting process – a supply of iron ore close to the surface, quantities of clay for building the furnace, plentiful hardwoods for making charcoal and sources of water for washing the ore.
From around 400 BC, when the invading Celts brought the skill from France, until the late 15th century, the process of producing iron from ore was carried out by heating the ore in a crude furnace, which became known as a bloomery, from the Saxon word ‘bloma’, meaning a lump of metal. The Ordinance Survey map shows the presumed site of a bloomery close to the pond behind 6 Cinder Hill Cottages.
A bloomery would usually be sited close to an outcrop of iron ore (or mine as it later became known), with supplies of wood and clay nearby. A team of miners would dig a pit some twenty feet deep through several seams of mine. They then excavated, backfilling as they went, finally leaving a large depression which in due course filled with water and became a pond. The miners would also create further holes when digging out the quantities of clay required for building the furnace. These also became ponds, so that bloomery sites can often be identified by a series of ponds which are not stream or spring fed.
A quantity of mine would be roasted on an open charcoal fire to produce a slightly porous iron oxide which could be more easily broken into small pieces. The furnace was then built up over a shallow depression, lined with hardened clay or sandstone, with alternate layers of charcoal and iron oxide, in the shape of a dome with an outer covering of clay up to 20 cms thick, leaving a hole at the top, four opposing holes just above the base, and a further hole at the base through which the charcoal was ignited.
Bellows were then inserted in the four holes and operated by teams of men for up to six hours, When the temperature reached 1200 ºC, the mine would begin to melt and a lump, or bloom, of metal would form at the base combined with slag or cinder. The bloomery was then demolished to recover the bloom whilst still red hot. It was then hammered into an ingot to remove the slag. The bloom would weigh about one-tenth of the original weight of iron oxide. The remainder – the cinder – accumulated in large mounds around the site – hence Cinder Hill.
A bloomery site is believed to have existed at Cinder Hill. Although no documentary evidence exists to support this, the area is surrounded by eight ponds, none of which are stream fed, suggesting that they are the remains of mine and/or clay excavations.
The bloom produced was only suitable to be hammered or wrought into different shapes, and could not be poured or cast into moulds. Blooms were not usually worked on the site but were sold to a local smith who would work them at his forge into horseshoes, nails, knives and tools, in fact any small utensil which could be made by hammering, bending or twisting the metal when red hot.
Two sets of accounts survive relating to a bloomery at Tudeley in the mid 14th century. These refer to the employment of four smiths to work the furnace; woodcutters and colliers to produce the charcoal; carters to transport the wood and the blooms; and miners to dig the mine and the clay. The smiths were paid a price per bloom and were entitled to keep every seventh bloom for their own profit. The woodcutters, colliers and carters were paid a price per ten or more loads, whilst the miners were paid according to the number and quality of the blooms produced.
The production rate was about one bloom a day and in 1334 an average size bloom sold for the equivalent of nine pence and cost about six and a half pence to produce. Twenty years later these figures had roughly doubled due to the acute shortage of labour resulting from the Black Death.
A survey carried out in 1976 identified around 146 bloomery sites between Heathfield and Eridge, so clearly they were once numerous, but the labour shortages in the second half of the 14th century would have reduced their number significantly as the whole bloomery operation was very labour intensive.
The bloomery at Cinder Hill stood on land which then belonged and still belongs to the Penshurst Estate and is unlikely to have continued operating later than 1540, when Sir Henry Sidney bought the Robertsbridge furnace which, having water-driven bellows and a brick furnace, was able to produce both wrought and cast iron in much greater quantities and far more cheaply.
Today, the only traces remaining of this once thriving industry are in the many place and field names in Kent and Sussex which incorporate words like cinder, mine, hammer and furnace.
Parish Magazine Article: Dec 2002/Jan 2003: by David Foster
See also article by Jeremy Hodgkinson on the Wealden Iron Industry.