TABLE 281 . 



VARIATION OF ELECTRICAL RESISTANCE OF CLASS AND PORCELAIN 



WITH TEMPERATURE. 



The following table gives the values of a, b, and c in the equation 



log R =. a + 6t + ct 2 , 



where R is the specific resistance expressed in ohms, that is, the resistance in ohms per centimetre of a rod one 

 square centimetre in cross section.* 



SMITHSONIAN TABLES. 



* T. Gray, "Phil. Mag." 1880, and " Proc. Roy. Soc." 1882. 



270 



