2.4 Manufacturing
Manufacturing takes place during certain phases of the movement of materials from natural resource sites toward consumers. Manufacturing plants form nodes upon the continuous paths of production flow, and must, therefore, always be located along the routes of transportation,
Materials move into an artisan's workshop or a great factory, into a rustic cauldron or an automatic refinery, are there transformed, and move out again to other stages. Manufacturing techniques involve the subjection of materials to physical or chemical change under controlled conditions in a restricted space, in a definite order, and on a strict schedule. The substances in process may be combined in stipulated proportions with other materials, as iron ores, coke, limestone and alloy metals are mixed in ferrous metallurgy, and as acids, cellulose and other reagents are blended in making synthetic fibers. Whatever the industry, materials are in movement and are simultaneously being modified.