Tables 493 and 494 



419 



TABLE 493. Variation of Electrical Resistance of Glass and Porcelain with Temperature 



The following table gives the values of a, 6, and c in the equation 



log R — a + bt + ct*, 

 where R is the specific resistance expressed in ohms, that is, the resistance in ohms per centimeter of a rod ona 

 square centimeter in cross section.* 



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

 TABLE 494. — Temperature Resistance Coefficients of Glass, Porcelain and Quartz dr/dt 



Somerville, Physical Review, 31, p. 261, 1910. 



Smithsonian Tadi.es. 



