TABLES 325, 326. 295 



DIELECTRIC STRENGTH. 



TABLE 325. Potential Necessary to produce a Spark in Air between more widely Separated Electrodes. 



This table for longer spark lengths contains the results of Voege, Ann. der Phys. 14, 1904, using alternating current 

 and "dull point" electrodes, and the results with steady potential found in the recent very careful work of C. Milt 

 ! ler, Ann. d. Phys. 28, p. 585, 1909. 



The specially constructed elec- 

 trodes for the columns headed 

 " cup electrodes " had the form of 

 a projecting knob 3 cm. in diame- 

 ter and having a height of 4.5 mm. 

 and 1.5 mm. respectively, attached 

 to the plane face of the electrodes. 

 These electrodes give a very satis- 

 factory linear relation between the , i 

 spark lengths and the voltage 

 throughout the range studied. 



TABLE 326. -Effect of the Pressure of the Gas on the Dielectric Strength. 

 Voltages are given for different spark lengths /. 



This table is based upon the results of Orgler, 1899. See this paper for work on other gases (or Landolt-B3rnstein- 



Fo^long'sp'ark lengths in various gases see Voege, Electrotechn. Z. 28, 1907. For dielectric strength of air and CO 8 

 in cylindrical air condensers, see Wien, Ann. d. Phys. 29, p. 679, 1909. 



SMITHSONIAN TABLES. 



