Contrasts in agglomeration: proto-industrial, industrial and post-industrial forms compared

For geographers and economists, urban agglomeration remains an enduring feature of the industrial landscape and a perennial source of theoretical and empirical interest. Curiously, despite this long-standing interest, there has been a remarkable tendency to explain agglomeration with reference to Alfred Marshall's trinity of external economies and industrial district model. In this paper, we seek to draw some contrasts in the form and causes of agglomeration. Our discussion proceeds by developing a simple and highly schematic taxonomy of what could be considered the emblematic forms of agglomeration in proto-industrial, industrial and post-industrial urban contexts. Highly simplified though they are, such contrasts highlight the changes in the spatial extent of agglomeration, the contribution of particular industrial sectors and types of external economy and of exports to the process of agglomeration over time. As such, there is an urgent need to reconcile the perspectives of economists and geographers in a renewal of the theory of agglomeration.