A florescent light uses low pressure gas to start an arc discharge. A starter interrupts an electrical inductor to produce a high voltage impulse to get it started. Heaters are also employed at each end of the tube to get the arc started. Mercury is added because of its low ionization potential. The tube must be next to a grounded plate because the arc starts in a wave across the tube. Newer versions employ higher frequencies to get the arc started. Rossi's arc operates at a fraction of a volt. Erika! He has also invented a new form of glow discharge lighting.