This article appeared in the Autumn 1972 (Issue #29) edition of the Kent Archaeological Review.
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The Wealden Iron Research Group (WIRG) was founded in 1968 to continue the work of Ernest Straker, who in 1931 wrote the classic, one-man survey entitled Wealdon Iron. An interim bibliography of Wealden Iron appeared in WIRG Bulletin Number 3 (Spring 1972). This article gives a brief account of the scope of Wealden Iron: the processes involved, the basic materials for production and investigation today.
IRONMAKING IN THE WEALD.
The Direct Process. The direct process involved the smelting of roasted ore in a crude clay or stone furnace (bloomery) and the forging of the resulting spongy mass into a bloom of wrought-iron. This process was introduced into Britain circa 500 BC (thus the Early Iron Age) and during the early part of the Roman Occupation the Weald was the chief area of production. The Indirect Process. In the late 15th century the indirect process was introduced. It involved the smelting of roasted ore in a water-powered blast-furnace with gigantic bellows operated by a cam on the millwheel shaft. The product was pig-iron which could be cast but not forged and so it was converted into wrought iron in a hammer-forge. First the carbon was burnt out in a finery furnace and then the resulting spongy "loop" was forged under a huge water-powered hammer into a bloom of wrought-iron.
Despite the relatively vast capital expenditure on bays and machinery and its complexity, the new process knocked out the old. A major reason is displayed in a comparison of the slags; bloomery -- circa 60 per cent of iron oxide; blast-furnace -- circa 1 per cent.
TIMBER AND ORE.
Ironmaking involved a high consumption of fuel (charcoal). Depletion of resources was, from the 16th century, sometimes avoided by rotational coppicing. The ore, almost always called 'mine,' occurred intermittently in various Wealden beds but notably at the bottom of the Wadhurst Clay and so, near its junction with the Ashdown sand. The ore was 'grubbed' either by open-cast methods or later by more methodical tell-pitting.' Some of the pits which litter the Weald are `mine-pits'; the bell-pits, so-called because they are said to be flared at the bottom, may be seen today as a series of small, shallow, circular depressions in `Mine-pit Woods.' These pits were back-filled and cannot be detected in cultivated fields. There were no mines in the Weald: 'mine' means ore'.
Bloomeries may be detected by concentrations of slag or by furnace-lining; occasionally an intact base is found. They were generally sited in the higher reaches of gills where running water had exposed the ore. Dating is by in-situ pottery or charcoal (C-14 testing). Occasionally artefacts like Classis Britannica tiles are found and a child's brooch was found on Ashdown Forest. A few sites have appropriate field-names -- Furnace, Forge, Cinder; Black or Beech Oven. Written evidence is scanty. Concentrations of slag are easy to find: one investigator found 30 in a small area in the Upper (Eastern) Rather basin; the Buxted team of WIRG has found 45. Some ten have been dated. All 75 were unknown to Straker.
Excavators, as distinct from the foragers, are contributing to Wealden Archaeology and History by their discoveries at Roman sites and WIRG Bulletins contain details of them.
Water-powered sites generally lie in valleys, though occasionally gills were dammed. Mainstreams were avoided: it was difficult to get a head of water where fall was minimal and bays would be immense. Generally the site is obvious because it is named -- most Wealden inhabitants know of a Furnace Hill, a Forge Wood, a Hammer Pond. It is still possible to find lost sites: the Buxted team has found four. Excavation is difficult -- the sites are occupied or overlaid with feet of alluvium. Nevertheless, at Chingley Forge a medieval layer has been reached and powered hammer-forging by the direct-process period is evidenced. Documentation is at once considerable and disappointing and many sites are unrecorded. The few detailed accounts which survive leave out much that we would wish to know. We do know that the first blast-furnace and forge were set up at Newbridge. in Hartfield circa 1496. Most of the known sites are noted in the famous Lists of 1574 which were drawn up by a civil servant of Queen Elizabeth I during a war scare. By this date there were about 115 sites. Thereafter WI declined and in the 18th century smelting with coke in the Midlands and North finally dowsed the glare of the furnaces and silenced the hammers which had banged at up to 150 blows a minute. The Weald waited somnolently for railways, motor cars, London hop-pickers and archaeologists.