TABLE 229. 

 CONDUCTIVITY FOR HEAT, METALS AND ALLOYS- 



213 



The coefficient k is the quantity of heat in small calories which is transmitted per second through 

 a plate one centimeter thick per square centimeter of its surface when the difference of tempera- 

 ture between the two faces of the plate is one degree Centigrade. The coefficient k is found to 

 vary with the absolute temperature of the plate, and is expressed approximately by the equation 

 k t = & [i + a.(t - Jo)]. o is the conductivity at t Q , the lower temperature of the bracketed pairs 

 in the table, kt that at temperature /, and a is a constant, kt in g-cal. per degree C per sec. across 

 cm cube = 0.239 x k t in watts per degree C per sec. across cm cube. 



* Copper: 100-197 C, k t = 1.043; 100-268, 0.969; 100-370, 0.931; 100-541, 0.902 (Her 

 ing; for reference see next page). 



flron: 100-727 C, kt = 0.202; 100-912, 0.184; 100-1245, 0.191 (Hering). 

 SMITHSONIAN TABLES. 



