Archaeometry 47, 1 (2005) 4 7 – 68. Printed in Great Britain * Received 20 August 2003; accepted 16 June 2004. © University of Oxford, 2005 Blackwell Publishing, Ltd. Oxford, UK ARCH Archaeometry 0003-813X © University of Oxford, 2005 February 2005 47 1 ORIGINAL ARTICLE Colourless Romano-British vessel glass M. J. Baxter, H. E. M. Cool and C. M. Jackson FURTHER STUDIES IN THE COMPOSITIONAL VARIABILITY OF COLOURLESS ROMANO-BRITISH VESSEL GLASS * M. J. BAXTER Division of Physics and Mathematical Sciences, School of Biomedical and Natural Sciences, Nottingham Trent University, Clifton Campus, Nottingham NG11 8NS, UK H. E. M. COOL Barbican Research Associates, 16 Lady Bay Road, West Bridgford, Nottingham NG2 5BJ, UK and C. M. JACKSON Department of Archaeology, University of Sheffield, Northgate House, West Street, Sheffield S1 4ET, UK Previous studies of colourless Romano-British vessel glasses have suggested that, regardless of vessel type, they show considerable compositional homogeneity. Intriguing differences in variability (as opposed to mean composition) have, however, also emerged. This paper reports on a compositional study of 243 vessels, that is larger and more carefully controlled than in previous studies of this kind. Unexpected compositional differences have been found both between and within the four vessel types studied. We discuss the implications of these results in the context of different models that have been proposed for glass-making and glass-working in the Roman world. KEYWORDS: GLASS, CHEMICAL COMPOSITION, ROMANO-BRITISH, LOG-RATIO ANALYSIS * Received 20 August 2003; accepted 16 June 2004. 8 University of Oxford, 2005 INTRODUCTION The aim of the research described here is to build on results derived from an analysis of col- ourless Roman vessel glass from Colchester (Baxter et al. 1995; Heyworth et al. 1995). This involved the analysis by inductively coupled plasma spectroscopy of 118 fragments, from four typologically distinct groups of vessels that spanned the mid-first to mid-third century period. Statistical analysis had shown that although the mean composition of types did not appear to differ much, there were noticeable differences in the variation of some oxides/elements within types. This form of compositional variation between the types raised hopes that it would be possible to explore the development of the Roman colourless glass-making and glass-working industry as it moved out of the Mediterranean area and into the northwestern provinces. This is not well understood at present. Of necessity, the analyses of the Colchester material worked with what was available, and some of the types were represented by quite small samples (of 21, 15, 29 and 53 fragments for the four types), and had more variants within types than was ideal. The present research was based on larger samples from the four groups, with greater control exercised over the number of variants present. The samples were from a range of sites