. Bulletin. Science. shop and stayed there for a number of years. After patenting a novel kind of electromagnet, he turned to the electrical lamp, and the innovations he in- troduced gave a tremendous impetus to the com- mercial application and exploitation of the dynamo. Jablochkoff found a means of producing a carbon arc that regulated itself without the use of any °^ He based his lamp (called a "candle") on the circumstances that if two carbons are placed side by side and parallel to one another, and so close that an arc could form at the ends, it would continue to burn
. Bulletin. Science. shop and stayed there for a number of years. After patenting a novel kind of electromagnet, he turned to the electrical lamp, and the innovations he in- troduced gave a tremendous impetus to the com- mercial application and exploitation of the dynamo. Jablochkoff found a means of producing a carbon arc that regulated itself without the use of any °^ He based his lamp (called a "candle") on the circumstances that if two carbons are placed side by side and parallel to one another, and so close that an arc could form at the ends, it would continue to burn until the carbons were entirely consumed. An insulating material—first kaolin and then a mixture of barium and calcium sulphates—was used to separate the two electrodes. The role of the spacer, called a "colombin," is not clear; apparently it provided some of the glow, and perhaps it reduced the voltage necessary to maintain the arc. Direct current was first tried, but since the positive electrode in an arc burns twice as fast as the negative, alternatmg current was used to make both burn at an equal rate. Each "candle" provided a light equal to that from 200 to 500 standard candles, depending on the generator and the particular circuit (fig. 80). With this device, Jablochkoff solved two of the problems of the subdivision of the electric light— that of placing several lights in the same circuit and that of reducing the intensity of the arc light. Al- though the "candles" flickered somewhat and only lasted for one or two hours, the light was whiter and brighter than that from gas, and it was not as blinding as that from the ordinary arc light. As used in an onyx globe (fig. 81), it gave a broad and diffused glow that seemed to have been occasionally on the pinkish side. Since there was no mechanism to be con- stantly fluctuating in the circuit and causing unstable operation of the other lamps, several "candles" could be placed in a
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Keywords: ., bookauthorunitedstatesdepto, bookcentury1900, booksubjectscience
