The Encyclopedia Americana (1920)/Spiegeleisen

SPIEGELEISEN, spē'g’l-ī''zĕn, a white cast iron originating in Germany, made from specular iron ore, or hematite, containing a large percentage of carbon and manganese. Being remarkably free from impurities, as phosphorus, sulphur, silica, it is largely used in the Bessemer process of steel-making for the purpose of reintroducing carbon. It reduces the iron oxide and is itself subject to oxidation.