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To make preservation in situ a serious option for the management of archaeological sites, research has to be done on the factors affecting conservation of different archaeological materials, including bone. A European project has been started which deals with bone degradation in a multidisciplinary way. The goals of the project are to develop techniques to describe the preservation of archaeological bone, to make a classification of soil environments according to their preservation potential and to detect what factors in the environment of the bone affect its conservation. One technique used in this project to determine the state of preservation of archaeological bone is histology. The relevance of this technique for archaeological heritage management research is discussed.

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The preservation of the osteological material at the medieval site of Apigliano, in southern Italy, is characterized by bones with highly crystalline, and altered, mineral phases. In addition to this, some material retains perfect histological preservation, with the exception of small microfissures present throughout this structure. Diagenetic porosity is indicative of collagen loss via chemical degradation. The levels of residual collagen in these bones are much lower than is predicted from simple models of gelatinization, and thus a more complex explanation for the state of preservation must be sought. Possible explanations for the rapid loss of bone collagen are considered, including a high-temperature event, the acceleration of hydrolysis due to liming and extreme wetting and drying cycles.

The investigation was undertaken to determine the main factors causing deterioration of bronze objects in soil by studying artefacts from archaeological excavations in progress. Objects that had been buried for 300-3000 years were examined. The composition of the metal, corrosion products, and surrounding soil was determined by chemical analysis. The possible effect of polluting sources and the environment in general was also taken into account. In total, 82 variables were coded, and their effects were statistically evaluated by multivariate analysis. Acidic soil, large deposits of sulfur pollutants in relation to the critical load, the presence of soot and soluble salt, and conditions giving access to water and air were found to accelerate the deterioration. A major part of the corrosion is likely to have occurred during the latest century. The results are of importance for the understanding and estimation of long-term corrosion of bronze objects in soil.

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The Raman spectra of polycrystalline samples of the metavanadates M"V,O,, (with M = Ca, Cd, Cu and Mg), belonging to the brannerite structural type, have been recorded. A general assignment, supported by comparisons with known vibrational properties of other oxovanadium species, is proposed. The compounds only give poorly defined IR spectra, which are not useful for the analysis of the vibrational behaviour.

temperature factors. It remains to be seen whether or not a sample with composition R6T6M 5 forms an identical structure but without T-T waist contacts. (1)% V= 252.6 (1) A 3, Z= 2, Dx= 3.732 (1) Mg m -3, F(000) = 272, T= 295 K. X-ray powder diffraction data (Cr Ka l, 2 = 2.28975 A, R = 0.083 for 35 reflections), X-ray single-crystal data (MoKa, 2=0.7107A, /z=5.86mm -l, R=0.040 for 672 reflections), and neutron powder diffraction (2= 1.8820/k, R t = 0.051 for 50 reflections). Isomorphism with thortveitite, 8c2Si207, is confirmed, but the refinements, using both a linear and a split-atom model, indicate a disordered bridging oxygen in the diphosphate anion with a non-linear P-O-P bond of 165.9 (1) °. The metal-oxygen distances conform with those of similar compounds. The JCPDS Diffraction File No. is 35-1497 for Mn2P207.Introduetlon. Among the condensed diphosphates there are often groups of isomorphous compounds, e.g. many divalent-metal M2P20 7 diphosphates crystallize with the thortveitite-type structure. The crystal structure of thortveitite, (Sc,Y)2Si207, was originally determined by 0108-2701/84/121995-05501.50 Zachariasen (1930). The space-group symmetry was reported as C2/m, which implies a linear Si-O-Si bond in the disilicate anion. The metal ions are octahedrally coordinated. Since then many studies of thortveitite-type M2X207 compounds (X = Si, P, V or As) have been published, which have in common the peculiarities that the bridging oxygen has a very large thermal motion, and the XO4 tetrahedra are more regular than they should be, considering that they share corners with each other (cf Cruickshank, 1961).