Detail view of blast furnaces and feed buckets at an unknown manufacturing plant, with a worker visible on the bottom left-hand side of the photograph. Used to chemically reduce and physically convert iron oxides into liquid iron or "hot metal," a blast furnace consists of cylinder-shaped steel stacks lined with refractory brick. Feed buckets are used to convey and deposit charges of raw materials, such as iron ore, coke, and limestone, into the interior of the blast furnace, where they eventually are converted to liquid slag and iron. This photograph is one of a set of fourteen stereographs detailing the production of iron and steel by various processes.