From 3 the iron which is produced from this oxidation – reduction, action – is a spongy mass which gradually falls to the furnace bottom, melting as it falls and taking into the solution carbon, Sulphur, manganese, etc. as it goes. The molten iron is collected in the hearth of the furnace, with the slag floating upon its surface. Tapping (the removal of the iron) of the furnace takes place about every 6 hours, the slag being tapped more frequently. When tapped the molten iron runs from the furnace through sand channels into sand pig beds (hence the term pig iron) or it is led into tubs, which are used to supply the iron in a molten condition to converters or Open hearth furnaces for steel manufacture. Pig iron is very brittle and has little use, an analysis of a sample is given below: