Archaeometry 47 (4)

The paper reports on the comparative evaluation of traditional and innovative methods for the investigation of mortar technology. Preliminary results of various approaches to determining the mix proportions in lime mortars with carbonate aggregate are presented. Quantitative analysis was tested on ad hoc prepared mortars of known composition containing carbonate aggregates of different origin (travertine and Bath limestone). Wet chemical methods, manual disaggregation and Digital Image Analysis of thin sections and cross-sections stained with Alizarin Red S were tested. The advantages and drawbacks of the different approaches are discussed, and applications to the analysis of archaeological mortars and plasters are highlighted. Includes

The paper discusses the compositional analysis of Roman colourless glass from three sites in Britain (16--22 Coppergate, York; Blue Boar Lane, Leicester; and Hartshill near Mancetter). The findings suggest that two broad compositional groups can be identified on the basis of the choice of the initial raw materials selected for glass production, in particular the sand. The largest of these groups is inherently different from the naturally coloured, blue--green glasses of the same period, while the other group is compositionally similar. Further subgroups are apparent on the basis of the decolourizers used. These glass groups are explored in the light of the current theories concerning the organization of glass production in the Roman world. Includes

Compositional analyses of ancient and historic glasses have often been interpreted in terms of the use of specific raw materials in glass manufacture. However, the known inhomogeneity of many glass-making raw materials and the insolubilities of some compounds make any explanation of compositional data problematic. The paper looks at three glass-making alkalis with a view to understanding how the compositions of these raw materials are carried through to the final glass. The chemistry and variability of the raw materials are discussed, as is their contribution to the final glass composition. In addition, the choices and decisions made by glassmakers are acknowledged in the final glass compositions. This combination of factors addresses the complexity of predicting the use of specific raw materials from the finished glass composition.