18th century bottle works on Irish Street, 200m north of Mote Hill

Reasons for Designation

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 involved the remelting of previously formed glass, and the production of new 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.

Despite the lack of surface evidence, the buried remains of Maryport glass house survive reasonably well. The monument is an exceptionally well-documented small 18th century glass bottle works, and is a rare example of this class of monument to offer the opportunity for further study of furnace and annealing ovens together with the range of associated buildings such as the clay mill, clay, bottle, kelp and korker stores. It dates from a period of experimentation with furnace and crucible design and as such has the potential to include innovative features.

Details

The monument includes the buried remains of Maryport glass house, an 18th century bottle manufacturing works located between Irish Street and the River Ellen 200m north of Mote Hill. It is not known for certain when bottle manufacturing began here but a map of 1745 depicts the glass house. An advertisement for the sale of the glass house in 1773 mentions ancillary buildings such as the korker and ash houses. A plan of the glass house produced during the 1780s depicts the circular cone containing melting furnaces together with three annealing furnaces and two flue entrances. The melting furnaces facilitated the re-melting of previously-formed glass, the production of new glass from raw materials, or a combination of the two activities whereby new materials were mixed with broken glass known as cullet. The glass was melted in clay crucibles placed in the furnace. The rapid cooling of molten glass gives rise to internal stresses and deformation and unless annealed the glass will readily shatter. The annealing furnaces here facilitated the process of re-heating previously molten glass to a temperature below the point where deformation begins. The glass was then gradually cooled thus resulting in a considerably strengthened finished product. The 1780s map also depicts a number of ancillary buildings including a clay store and clay mill for producing the crucibles, a bottle store, and a kelp store where seaweed used as an alkali in the glass-making process was stored. One other building shown on the 1780s map of the glass house is a korker store. Korker is an obscure term, possibly a corruption of the word celcar, which refers to the main constituents of glass which have been partially heated to produce an unmolten material which could be ground up ready to place in the crucible for the main melt. The more familiar term for this process is fritting thus the korker store is considered to represent the store room for fritted material awaiting the final melt. The glass house is thought to have ceased production towards the end of the 18th century and by 1803 the site had been taken over by shipbuilders John Peat & Co. During the mid-to late 1980s parts of the glass house were exposed during land grading operations. Remains of the clay mill and store together with remains of the korker store were visible, while the cone and furnace area appeared relatively undisturbed. These remains have since been reburied. All fence posts, gateposts, railings and the retaining wall on the west bank of the River Ellen are excluded from the scheduling although the ground beneath these features is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.

Legacy

The contents of this record have been generated from a legacy data system.

Legacy System number:

34984

Legacy System:

RSM

Sources

Books and journals
Parsons, W, White, W, A History, Directory and Gazetteer of Cumberland and Westmorland, (1829)

Other
In SMR 3577, Bolton, Edgar, Maryport: Potteries and Glasshouses - Keeping It Simple,
To Robinson,K.D. MPPA, Martin, Eric , Maryport Glass House, (2001)
Map in SMR Ref 6175, Cumbria County Council,
CRO D/CU/Compt.7, Maryport Glass House,

End of official list entry

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