While the arcs with plain carbons are bluish-white, those with carbons containing calcium fluoride have a notable golden glow. 弗兰克·刘易斯·戴尔.爱迪生的生平和发明.
The use of electrical current in twelve principal cities in the United States was distributed in 1898 as follows: Lamps, arcs, and motors in sixteen candle power equivalents. Edward W. Byrn.十九世纪发明进展.