An English metallurgist named Mushet discovered that addition of manganese ridded the metal of injurious gases and oxides and what is known as “red-shortness.” After a period of difficulty without it Bessemer acknowledged the necessity of manganese and adopted its use. It had before this been used in crucible steel. Upon turning down the converter at the drop of the flame, the blast is turned off and a smaller ladle is run in on a track above. This brings a molten mixture of irons, usually known as “spiegel” or “spiegeleisen” which contains just enough carbon, manganese and silicon to give to the whole of the molten metal in the converter the metalloids needed to make of it steel of the composition desired. This addition also accomplishes the “deoxidation” of the metal. By deoxidation we mean that the iron is relieved of the oxygen and gases which have remained as a result of the blast. This is necessary in order to give proper fluidity for pouring and the best physical properties to the finished steel. After “recarburization,” as this addition of manganese-silicon-carbon metal is called, the steel and slag are quickly poured out into a ladle waiting below from which the steel is “teemed” (i.e., poured), through a “nozzle” or hole in the bottom into ingot molds arranged on trucks on the railroad track which runs through the building. [Illustration: TEEMING THE FINISHED STEEL INTO THE INGOT MOLDS ] When the molds have been filled and a strong crust develops on the steel the cars are pulled to the “stripper” where the molds are removed, leaving the white-hot ingots standing on the cars. The ingots mentioned in the chapter on Cementation and Crucible Steel were usually small enough that one pot of 100 pounds of metal filled the mold. A four pot furnace therefore produced 400 pounds. Now for the first time, we are talking in _tonnage_ figures. Instead of a batch of steel making four 3″ × 3″ × 36″ ingots of 100 pounds each, the ordinary “heat” of Bessemer steel from the 15–ton converter gives six or seven ingots about 18″ × 20″ × 60″ in size. Each of these weighs about two tons. The total is 30,000 pounds. From the stripper the ingots go to the gas-fired soaking pits where the molten interiors of the ingots gradually solidify by cooling while the outer crusts are reheated. After equalizing the temperatures of exteriors and interiors in this way, the ingots are white-hot again and ready for rolling. [Illustration: MOLDS BEING STRIPPED FROM INGOTS ] The purpose for which the steel is intended, of course, determines the shapes and sizes into which the ingots are rolled. For rails they are rolled down directly, each ingot making about six rails, of thirty-three-foot length. For most other purposes the ingots are rolled in the slabbing mill into billets or slabs which are of intermediate shapes and sizes which are reheated and further rolled down into axles, bars, shapes, wire or other products.