250 



Tables 259, 260. 

 DIELECTRIC STRENGTH. 



TABLE 259. — Dielectric Strength 0! Materials. 

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



TABLE 260. — Potentials In Volts to Frodnce 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 Mo^cicki, 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. 



