Heavy industries, from steel and molecules to the Cloud

International audienceThe expression 'heavy industry' appeared with the acceleration of industrial development from the nineteenth century onwards, alongside the notion of so-called 'light' industry. The distinction was based on the levels of investment necessary for the construction and operation of the industries concerned, sectors associated with the production and transformation of raw materials such as mining, metallurgy, electrometallurgy, paper-making and first-stage chemical processing industries. As their techniques evolved, certain other industries came to qualify for this 'heavy' industry classification, for example the IT industry in the twenty-first century. If the category offers certain facilities of analysis for economists and financial experts, from the point of view of the history of technology it is difficult to give a coherent account of a field which covers industries of a highly heterogeneous nature. Amongst metals, historiography has paid particular attention to the study of the iron and steel industry. After all, the uses of ferrous metals are both ancient and extremely important in quantitative terms. The history of paper-making is another sector with a long history and a rich bibliography. In both these cases, the geographical territories covered are vast ones, corresponding with the diversity of the techniques employed and the relative ease of their application. Unlike these two sectors, that of non-ferrous metals has so far elicited fewer studies and many of these are quite recent. The chemical industry is another special case. The exceptional variety of production techniques and of products, especially since the 1950s, and in a broad range of spheres of consumption-civil and military, foodstuffs, industry, agriculture, textile manufacture, cosmetics, health products, etc.-has given rise to much research, even if important areas still remain unexplored