5. The Archaeological Evidence for the use of Muffles in Pipe Kilns

In the course of this study 145 separate assemblages have been traced, examined and recorded. Material from a further 13 sites, noted in various journals, remains undiscovered despite all efforts. Whilst it is possible that some of these may yet come to light, others are probably permanently lost. Listed below, by County, are the locations of sites from which these assemblages derive.

Table 1. List of site locations by County and Country.

Of the 145 assemblages examined, 90 contain fragments from muffles. In only two cases out of the 90 are the muffle fabrics not reinforced with pipe stems. These are Church Field, Rainford and Cottage Street, Leeds. To be sure of the validity of identification it is necessary to look again at the definition of a muffle:

A chamber, case or box of refractory material, which is built in a furnace, and used to heat articles out of direct contact with flames or other products of combustion. It serves a purpose similar to a SAGGAR, but being larger, is more suitable for some purposes (Searle 1930, 336)

Fragments from a vessel displaying fire-damaged outer surfaces, with clean inner surfaces, must come either from a saggar or a muffle. The question appears to be largely one of scale. A number of pipe kiln muffles, discussed in previous work (Peacey 1982, 3-17), display common features which may in themselves prove to be diagnostic (Figure 4). These are luted inner surfaces and pipe stem reinforcing of the fabric. To these can be added other features that certainly are diagnostic - external buttressing and internal shelving, both products of increased scale. Muffle material, previously examined, also displays heavier slagging than that generally seen on saggars. This is a result of the fixed position occupied by a muffle relative to the fire. In summary, the size of a saggar is limited by the need to carry it, when full, in and out of the kiln. Any fragments from a larger vessel displaying fire damage ranging from flash glazing to heavy slagging, on their outer surfaces only, can, therefore, be assumed to belong to a muffle. Any fragment with, in addition to the above, either external buttressing or internal shelving is certainly from a muffle. Stem reinforcing may also be a distinguishing feature.

Prior to this current study, prop type muffle buttresses had been recognised and described from Arcadia Buildings, Southwark (ibid, 3-12]; bar type buttresses and internal peripheral shelves of both step and projecting (cornice) type from Waverly Street, Bristol (ibid, 10-13). All of these features can now be seen as standard practice over a wide area (Table 2). A muffle feature, noted from Arcadia Buildings, Southwark, which has not proved to be of widespread use is the ridge-shaped deflector. This was constructed of a piece with the muffle body, projecting from it to cover that part of the upper surface of the muffle supports between the outer edge of the muffle base and the brick shell of the kiln superstructure (ibid, 6 and 12).

A further buttress type has emerged in the course of this study. This is in the form of a short bar or billet placed vertically between the outer surface of the muffle wall and the inner surface of the kiln shell. The lower extremities of these buttresses are hemispherical whilst the upper, which might be simply truncated or groined, are thumbed outwards to blend into both muffle wall and kiln shell (Figure 4c). These have been termed 'tear drop' buttresses after those first recorded from Castle Street, Aylesbury, which most closely resemble this form (Moore 1979, 127-8).

The type of material commonly used for muffle construction - clay matrix reinforced with pipe stems - can be seen in Figure 11.

Muffle material, recorded in the catalogue, is subdivided into two primary categories. These are muffle wall and muffle base. Additional categories are used for secondary features and detached material. All fragments from the body of a muffle, regardless of any other secondary feature, are included in either the wall or base category. The secondary categories are only used when the feature described has become separated from the host muffle. The presence of secondary features such as buttresses and shelves are recorded in the introductory note which precedes the tabulated entry (see Glossary 2 for details of the categories used in the catalogue for muffle material, together with definitions and diagnostic criteria).

Table 2 and Map 1 show those sites from which muffle material has been identified.

Map 1 shows the distribution of the sites from which muffle fragments have been recovered. The quality and size of the assemblages varies from chance finds to large excavated groups from kiln sites or waste tips. By detailed examination of these larger assemblages, muffle types can be formulated. This in turn leads to the establishment of a muffle typology against which the isolated fragments can be compared. In the following pages, evidence from the larger and more significant groups is examined in chronological sequence. Where appropriate, sketch reconstructions of muffle types, based on named assemblages, are included.

5.1 Seventeenth-Century Muffles

5.2 Eighteenth-Century Muffle Developments

5.3 Nineteenth-Century Muffle Developments

5.4 Pipe Bowls in Muffles


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