Table 229. 

 CONDUCTIVITY FOR HEAT. METALS AND ALLOYS- 



213 



The coefBcient 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 

 ki = kx[_i + a{i - io) j. ko is the conductivity at (0, the lower temperature of the bracketed pairs 

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

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



Substance 



Aluminum . 



Antimony . 

 Bismuth. . 



Brass . 



" , yellow, 



" ,red... 



Cadmium,pure 



Constantan 

 (60 Cu+40 Ni) 

 Copper,* pure 



German silver 



Gold 



Graphite . . . 

 Iridium .... 

 Iron,t pure . 



Iron, wrought 



" steel, 1% 



C 



Lead, pure 



Magnesium. 



Manganin . . 



" (84CU+4 

 Ni 1 2 Mn) 



376 



+.0030 

 + 0020 

 +.0014 

 -.00104 



-.0021 



+.0024 

 +.0015 



+.00227 



-.00013 



+.0027 

 -.00007 

 + ■ 0003 

 -.0005 



- . 0008 



— . 00008 

 -.0001 



—.0001 

 +.0026 





Substance. 



Mercury . 



Molybdenum 

 Nickel 



Palladium.. 



Platinum.. . 



(I 



Pt 10 % Ir . 

 Pt 10% Rh 

 Platinoid . . 

 Potassium. . 



Rhodium. . . 

 Silver, pure. 



Sodium. . . . 

 Tantalum. . 



Tin. 



, pure. . . 

 Timgsten. . . 

 Tungsten. . . 



Wood's alloy 

 Zinc, pure. 



1600 

 2000 

 2400 

 2800 



-160 



17 0.476 



0.249I 



o. 272 f 



0.294I 



0.313/ 



0.31Q 



0.278 



0.2653I 

 o. 2619 J 



+.0055 

 -.0001 



—.00032 

 - . 0009s 

 -.00047 

 +.0010 



+.00051 



+.0002 

 +.0002 



+.00023 

 +.00016 



—.00016 



,3i w 

 ^ C 



References: (1) Lees, Phil. Trans. 1908; (2) Jaeger and Diesselhorst, Wiss. Abh. 

 Phys. Tech, Reich. 3, 1900; (3) Angell, Phys. Rev. 1911; (4) Lorenz; (5) Macchia, 

 1907; (6) Barratt, Pr. Phys. Soc. 1914; (7) H. F. Weber, 1879; (8) Hornbeck, Phys. 

 Rev. 1913; (9) Worthing, Phys. Rev. 1914; (10) Worthing, Phys. Rev. 1917. 



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

 ing; for reference see next page). 



tlron: 100-727° C, ^t = 0.202; 100-912°, 0,184; 100-1245°, 0.191 (Hering). 

 Smithsonian Tables. 



