1. candle, jablochkoff An arc lamp without regulating mechanism, producing an arc between the ends of parallel carbons. It consists of two parallel rods of carbon, between which is an insulating layer of non-combustible material called the colombin. Kaolin was originally employed for this part; later, as the fusion of this material was found to short-circuit the arc, a mixture of two parts of calciumsulphate and one of bariumsulphate was used. The carbons are 4 millimeters (.16 inch) thick, and the colombin is 3 millimeters (.12 inch) wide and two-thirds as thick. A little slip of carbon is placed across the top, touching both carbons to start the arc. Once started the candleburns to the end, and cannot be restarted after ignition, except by placing a shortconductor across the ends, as at first. The Jablochkoff candle may now be considered as virtually extinct in this country. In France at one time a greatnumber were in use.
To keep the carbons of equallength an alternating currentmust always be used with them. Special alternating combinations were employed in some cases where a direct current had to be drawn upon.
Definitions of candle, jablochkoff
