Imperator Crassus. Julius Caesar arrives at the House of Crassus and after a brief tussle with Crassus' guards, is welcomed by the man himself. Crassus strikes an alliance with Caesar in order to bring an end to Spartacus' rebellion. He orders Caesar to remain unshaven and the purpose of this is not revealed.
1 Lanthanum oxide additive to tungsten is used in gas tungsten arc welding electrodes, as a substitute for radioactive thorium. 2  Various compounds of lanthanum and other rare-earth elements (oxides, chlorides, etc.) are components of various catalysis, such as petroleum cracking catalysts.
Lanthanum was discovered by Carl Gustaf Mosander in 1839 when he was studying a sample of cerium. Lanthanum is a transition metal found in the lanthanide series of the periodic table. It is a rare earth metal that has 57 protons in its nucleus with the chemical symbol La. Lanthanum is soft and ductile. Lanthanum is toxic if inhaled. Lanthanum ions have been used as medical tracers to monitor calcium ions.