PHOTOMETRY OF THE ELECTRIC ARC 



139 



that with a pointed form there was 0.710 hefner unit per 

 watt and that for a flat curve there were 1.024 hefner 

 units. They also found that the candle power decreased 

 as the number of alternations increased. 



Comparison of Different Kinds of Arcs. A comparison 

 of candle power of different arc lamps has been made by 

 Blondel 1 and his results are given in the following table. 



Alternating-current Lamps. 



1 Zeidler, Elektrotechnishe Verein von Berlin, Dec. 23, 1902. 



2 Matthews, second report, p. 30, and third report, p. 17, N. E. L. A. A. 



M. W. Holmes, Elec. World, 43, 1053; 1904. 



Czudnochowski, Vertrag der Deutschen Phys. Gesellschaft, 1903, No. 7. 

 6 Essais des Laboratoire de la Soc. Auer de Paris. 



6 Westinghouse circular. 



7 Ladoff Eel. Elec. 



8 Monash, Elektrische Beleutung, p. 179. 



Essais des Laboratoire central d'Electricite de Paris. 



1 Trans. Intern. Elec. Cong., St. Louis, 2, 755; 1904. Eel. Elec., 53, 

 68; 1907. 



