Greenwich Borough Museum has recently undertaken the move of the earliest salt-glazed stoneware kiln yet found in Britain.
The kiln, dated to the period 1610 - 1640/60 was found during an excavation in 1974 of a site intended for redevelopment, close to the Thames in Woolwich. The project had originally intended to look for phases of early occupation of Woolwich and had planned six weeks of work. Following discovery of the kiln sites, the excavation, sponsored jointly by the Borough of Greenwich and the then Dept. of the Environment, was extended to four months. The site was flanked on its northern side by the River Thames and enclosed by the High Street to the south, with Bell Water Gate on the east and Surgeon Street to the west. The site is now occupied by the Council's 'Waterside Leisure Centre'. Grid reference is TQ 433 793.
Despite wells, cesspits and deep nineteenth century basements which had cut through most traces of any earlier occupation, the excavators uncovered the remains of two kilns and an earlier 'clay settling-pit'.
Although the Plumstead/Woolwich area had a well-documented pottery industry through the eighteenth and nineteenth centuries, the existence of this early group of kilns was unsuspected.
The square clay pit was clay-lined and revetted with timbers. It is suggested by the excavators to predate both kilns. Its fill material was interpreted as waste from an earlier undiscovered kiln. The remains of two kilns were located. The first was found below the nineteenth-century houses fronting Surgeon Street. It was a round, brick-built structure with twin flues, used for the production of both glazed and unglazed red earthenware of a type common in London in the seventeenth century. It was dated by clay pipes in the demolition layer to 1640-1680. The internal diameter was 2.50m; part was lost due to later cess-pits and a sewer. A possible roadway was associated. Two brick walls, one found by each stoke hole, were interpreted as 'Wind baffles'.
The second kiln is unique. It is the only kiln producing salt-glazed stoneware of this period yet found in Europe. This is the kiln which has recently been moved for the second time since its discovery. It lay to the north of the earthenware kiln and was sealed by its northeast stoke hole and possible 'fuel storage area'. The brick-built remains survived to just above floor level, complete with three internal flues. The external diameter measured 2.25m., the internal diameter 1.60m. Much of the western outer wall had been lost due to sinking of later cess-pits. The stoke hole and firebox area were below the ground surface and had been sunk into the natural of Thanet Sand. No wood was found but timber revetting was suggested by staining on the sand. The only structures associated were a chalk footed wall to the east, which was probably added at a later stage and which may have enclosed the kiln in a yard. To the east of the wall was a clinker and ash path.
Large amounts of pottery were found associated with this kiln, the majority being Bellarmine jugs, but also found were Westerwald wares. Both these ceramic types were originally produced on the continent from the sixteenth century onwards and were imported into Britain. This kiln is important, being the first to produce salt-glazed stoneware in Britain. Previously, John Dwight's pottery in Fulham had been considered the earliest, with its patent dating from 1672.
The kiln is suggested to have had only a short life or to have perhaps been in production experimentally. The large amount of fused waste and unsuccessful products and the fact that the Woolwich pottery was never mentioned by Dwight may support this theory.
Due to its good state of preservation and associated range of pottery, it was decided at the conclusion of the excavation that the kiln should be lifted and retained as a whole. Along with conservation experts from the British Museum, the Dept. of the Environment took charge of lifting the kiln, enclosed in a specially designed support. It weighed in for the lift at c.40 tons and was deposited in one of the Council's depots for storage.
When the Council recently undertook a reorganization of its work depots, the local museum was asked to arrange removal of the kiln to an alternative site. With the help of a grant of £1,000 from the Area Museum Service for South East England, the kiln was again lifted. This time it topped 43 tons after being sprayed with water for a week prior to its journey. The move was made using a low loader and with a police escort. The kiln was wrapped in the Museum's banner for its journey through Woolwich and is now redeposited in a secure location. The finds from the excavation and the associated archive are available for study through Greenwich Borough Museum.
Finds include both the products from the stoneware kiln and from the later earthenware kiln. Videos of both the 1974 and the 1990 move may also be viewed by prior arrangement.
Barbara Wood
Assistant Curator, Greenwich Borough Museum
