The deformation of the earth's crust under superposed loads is considered as a problem in structural mechanics. The crust is treated as a uniform, elastic, thin, spherical shell, and the mantle is treated as an enclosed viscous liquid. Equations relating loading and crustal response are developed. Loadings may be spatially concentrated, locally distributed, or global and may be applied as a steady‐state or transient condition. Crustal displacements under reservoir loadings, glacial sheets, and sea‐level rises are predicted and agree well with observations both in magnitude and in time. The Wisconsin glaciation in North America is treated in particular.

In this paper the author previews a current international study of impacts of technological change on urban activities and interactions, and hence on urban built form. He considers various trends and factors of technological change, and the mechanisms through which they are influencing urban form. The nature of this impact is also discussed. The author introduces two basic measures of urban form and interaction, and maps urban activities and interactions onto this two-dimensional space. Some of the broader impacts of technological change may then be considered as movements in this space. Information systems for monitoring the effects of technological change, for quantitative analysis of these impacts, and for prediction of further impacts of change are also discussed. Last, the implications for planning are considered. One possible model for use at various levels in this study is outlined in an appendix.

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This note describes a different approach to urban modelling, resulting in a new, more general form of model. The model can be used for prediction, prescription, explanation, or evaluation; or to distinguish between the objectives of individuals, the planning authority, and the community. It is utility maximizing, and also entropy maximizing, and includes diversity of activities in zones. It relates land use and transport decisions and allows dispersal of urban activities to be analysed.

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