The terms ‘heavy industry’ or ‘light industry’ are normally used far too loosely. Definition proves much harder than the quick wave of the hand over a map or the glib labelling of a district would suggest. Transistor manufacture and the production of stationery are clearly enough on one side of the fence; shipbuilding and the production of large pressure vessels on the other. Size, volume and weight of product are important in the classification for they affect the type of input, the material handling equipment of the plant and the minimum size of the whole operation. When large masses of material, perhaps hot or corrosive, are involved much investment in plant is required; characteristically, therefore, heavy industry has a high capital/labour ratio, and, in spite of big labour forces, a high value of output per employee. In general products are sold not to individuals but to other manufacturing industries. Such indices of heaviness are admittedly crude, for many industries or individual firms span a much wider range than can be comprehended under the title of ‘heavy’ – the big chemical firms for instance make pharmaceuticals and gardening requisites and the steel industry's products range all the way from giant castings and forgings to the razor blade steel and umbrella frames of one major Sheffield plant. A number of heavy industries, some new, some long established, can be readily isolated, bearing some, but not in each case all, of these characteristics.