250 TABLES 259, 260. 



DIELECTRIC STRENGTH. 



TABLE 259. Dielectric Strength o! Materials. 

 Potential necessary for puncture expressed in kilovolts per centimetre thickness of the dielectric. 



TABLE 260. Potentials In Volts to Produce a Spark In Kerosene. 



Determinations of the dielectric strength of the same substance by different observers do not agree well. For a dis- 

 cussion of the sources of error see Mocicki, Electrotechn. Z. 25, 1904. 



For more detailed information on the dependence of the sparking distance in oils as a function of the nature of the 

 electrodes, see Edmondson, Phys. Review 6, 1898. 



SMITHSONIAN TABLES. 



