Cerium is the most abundant of the Lanthanide series and is not found free as an element but in minerals in the earth's crust. Cerium is used with other lanthanides to produce alloys for use as flint in cigarette lighters. It is also used in arc lighting. Cerium oxide has a wide use as a catalytic convertor to reduce carbon monoxide emissions. Cerium was discovered in 1803 by Jacob Berzelius and Wilhelm von Hisinger who isolated it in the mineral cerite as a reddish brown element. It is a solid metal at room temperature with a melting point of 795°c and a boiling point of 3443°c.