The famous weight-losing principle of Alfred Weber has provided a basis for classifying industries into the primary types, and has been widely used as a criterion of what is and what is not the most economic location for a particular process of production. In the old Russian Empire, industrial development was mainly in the west, and to a long-term view its location was far from rational according to any of the usual criteria. Heavy industry, for reasons that were obvious enough, was located in the Donbas-Dnieper region between the rich coal deposits of the Donbas and the ore deposits of Krivoi Rog some two hundred miles to the west. In its long-term programme for the geographical distribution of industry Soviet planning has treated the fuel and power network as the foundation-plan of its structure. In the First Five Year Plan the traditional industrial districts still had the main emphasis in electric power development.