Scheduled Monument: Glassworking remains in Glazier's Hollow, 330m south of Kingswood Cottage (1020705)

EXTRACT FROM ENGLISH HERITAGE'S RECORD OF SCHEDULED MONUMENTS MONUMENT: Glassworking remains in Glazier's Hollow, 330m south of Kingswood Cottage PARISH: MANLEY DISTRICT: VALE ROYAL COUNTY: CHESHIRE NATIONAL MONUMENT NO: 33880 NATIONAL GRID REFERENCE(S): SJ53227240 DESCRIPTION OF THE MONUMENT The monument includes the earthworks and buried remains of a late medieval glass working site in Delamere Forest. The site was identified in 1933 and partially excavated during 1933-5. The excavations revealed a dense concentration of glass fragments including painted glass imported to the site as cullet (scrap glass for remaking). In addition a glazed brick floor was uncovered and this may be a part of the original furnace floor. Crucible fragments confirm the presence of glassmaking here. Building stone on the site and reused material in the field walls bears traces of spilled glass. Associated with these remains were sherds of 15th century pots and a silver penny of Edward I. The site was further examined by excavation in 1947 and the report concluded that the area of the glassmaking debris covered about 12 sq m, and that there were probably more remains to be discovered in the immediate vicinity. The excavators thought that the production of glass at this location was confined to window glass, both clear and coloured, and that the furnace was fired with wood from the forest around it. Work probably ceased here when the use of wood was forbidden by law in royal forests in about 1615. However, there is a plan of the forest dating to 1627, which marks this site as `Glassen House'. A concrete footbridge crossing the brook in the centre of the site is excluded from the scheduling, although the ground beneath it is included. ASSESSMENT OF IMPORTANCE Glass has been produced in England since the Roman period, although field evidence is scarce until the late medieval period. Wood was the main manufacturing fuel up to the early 17th century, so the industry was located in woodland areas, particularly the Weald. From about 1610, production shifted to the coalfields. Glass production requires three major components: silica, alkali and lime, together with colouring material for certain products and decolourisers for clear glass. Lead was also used in the production of certain types of glass during the Roman period and after the 17th century. The manufacturing process involves three stages, fritting, melting and annealing. Fritting was a common practice before the 19th century involving heating the main glass constituents to produce an unmolten material for grinding, melting and annealing. Melting glass from raw materials. Until the late 19th century, glass was normally melted in pre-fired crucibles of refractory clay, on stone benches called sieges, within the melting furnace. Use of coal as the preferred fuel and automatic bottle-making machinery in the 1880s led to changes to the melting furnaces and the use of larger furnaces, hitherto conical structures over circular furnaces. Regenerative furnaces were developed in the 1860s, and tank furnaces for bulk melting quickly followed. Flat-glass production methods were made obsolete by the Pilkington float-glass system of 1959. The third process is annealing. Because the rapid cooling of molten glass can give rise to internal stresses, glass was treated in furnaces designed to heat the glass to a point where deformation begins, then cooled gradually. In the 19th century conveyors were introduced to take glass through a hot zone into cool air. Features on glass manufacturing sites include various types of furnaces, producer-gas plants for the making of gas from coke at 19th century glassworks, bottle-making machinery, blowing irons or pipes for blowing glass, glass residues and various buildings used as stores or warehouses. A total of 135 glass production sites (representing about 25% of the estimated national archaeological resource for the industry) have been identified as being of national importance. This selection, compiled and assessed though a comprehensive national survey of the glass industry, is designed to represent the industry's chronological depth, technological breadth and regional diversity, and to include all the better preserved glass sites, together with rare individual component features. The glassworking remains in Glazier's Hollow, 330m south of Kingswood Cottage represent the only reliably located wood-fired glass furnace complex from the late medieval period in the north west. It retains considerable potential for discovery of further glass making remains. The site is on land with full public access and footpaths both through the area and beside it, consequently it has a high profile as an educational and recreational resource for the community. MONUMENT INCLUDED IN THE SCHEDULE ON 05th July 2002