X-RAY FLUORESCENCE AND DENSITY MEASUREMENTS ON SURFACE-TREATED ROMAN SILVER COINS*

Some 630 Roman silver coins excavated at Augusta Raurica (Switzerland) have been analysed by non-destructive X-ray fluorescence and X-ray diffraction. Furthermore, the density and the weight have been determined. The measured average density of plated and massive depletion-silvered coins is lower than the density calculated from the chemical composition, whereas massive coins display equal values for both of the densities. Based on experimental X-ray investigations of modern silver (tempering, acid treatment, production of corrosion layers), the nature of corrosion products on silver, their impact on surface analysis, and aspects of wearing-off by circulation are briefly discussed.     

WHO AND WHY IN PALAEOLITHIC ART

Summary. No consideration has ever been given to the possibility that women may have had a part in the execution of European Upper Palaeolithic art; however, an examination of the history of research in this field suggests that preconceptions, prejudice, and the acceptance of unproved theories have perhaps been responsible for the view that it was a male-only activity.
Some of its so-called 'religious' aspects are reconsidered, and re-explained from a female perspective in the light of an experimental attempt to reproduce Palaeolithic plaques with superimpositions. The results of this experiment suggest that Palaeolithic art may well have been multipurpose, at least some being illustrative and part of a general visual communication system — perhaps a forerunner of written communication. It seems probable that all members of society, especially women, were involved.     

A COMPARISON OF METHODS FOR ESTABLISHING FATTY ACID CONCENTRATION GRADIENTS ACROSS POTSHERDS: A CASE STUDY USING LATE BRONZE AGE CANAANITE AMPHORAE*

Canaanite amphorae fragments in fabrics believed to be associated with the bulk transport of vegetable oils from the fourteenth‐century BC site of Amarna, Egypt, have been examined. A comparison is made between solvent extraction, saponification and the use of TMTFTH (m‐trifluoromethylphenyl)trimethylammomum hydroxide, used here for the combined extraction and derivatization of ceramic‐absorbed organic residues. Extracts were studied using gas chromatography and gas chromatography‐mass spectrometry. The extraction of fatty acids from small ceramic samples has established concentration gradients of absorbed organic matter from the inner to the outer surfaces of the sherds.     

USING OPTICAL COHERENCE TOMOGRAPHY TO EXAMINE THE SUBSURFACE MORPHOLOGY OF CHINESE GLAZES

Optical coherence tomography (OCT), a new method for ceramics research, is a nondestructive, three‐dimensional tomography system, which provides subsurface morphology visualization of samples based on the refractive index or dielectric constant differences in the target specimen. In this study, seven shards from different Chinese kilns of Song and Yuan dynasties (10–14th centuries) were scanned to visualize the subsurface morphology of their glazes. The images revealed unique phase assemblage modes in different samples. The results suggest OCT may be used to identify ceramics and provide information about their manufacturing technology.