ON THE ORIGIN OF GREY AND BLACK ‘COLOURS’ OF ANCIENT POTTERY: ROLE OF Fe AND Ti4+ IONS

It is shown, from comparisons with the optical absorption of minerals, that the black and grey colours of pottery can arise from Fe²⁺ Fe³⁺ and Fe²⁺ Ti⁴⁺ charge-transfer (or electron-hopping) processes, the cations being located at the centres of adjacent edge-sharing octahedra.     

Models of Space Searching in Urban Areas

City dwellers occasionally must seek jobs, dwellings, or particular services or goods. Two very different ways exist by which the individual may conduct such a search. Lacking prior information, the person may elect to visit perceived possible locations until an appropriate one is found. Alternatively, an address may first be ascertained and then visited by finding a path to it. Clearly, there is a substantial difference between these two methods in terms of the amount of spatial movement they require in order to satisfy the searcher's needs. In this paper, this difference is modeled for situations that vary in terms of the density of acceptable end points of the search, as well as in characteristics of the signs of these end points, their patterns, and the level of information with which the searcher may begin.     

REVIEW

Taruru: Aboriginal Song: Poetry from the Pilbara. By C. G. von Brandenstein and A. P. Thomas. Rigby Ltd., Adelaide, 1974. Pp. i–xx, 1–91. Price $A7.95.     

A system for classification and description of the horn cores of cattle from archaeological sites

A system is proposed for the classification and sexing of the horn cores of cattle recovered from archaeological sites. The cores are first divided into four groups depending on their length. The terms “small”, “short”, “medium” and “long horned” are given to these groups but bear no relation to the names used for modern breeds of cattle. After differentiation according to length, the sex of the core is designated by visual appraisal of the shape, curvature and angle of attachment of the cores to the frontal bones. It is not claimed that the sex of individual horn cores can always be established but from the sample of 80 cores that we tested by statistical analysis (presented in an appendix) it was evident that the categories based on length and assessment of sex did separate out as expected.