208 



Table 229. 

 DIFFUSIVITIES. 



The diffusivity of a substance = h2 = k/cp, where k is the conductivity for heat, c the spe- 

 cific heat and p the density. (Kelvin.) The values are mostly for room temperatures, about ib C. 



Material. 



Aluminum 



Antimony 



Bismuth 



Brass (yellow) 



Cadmium 



Copper 



Gold 



Iron (wrought, also mild steel) 

 Iron (cast, also i% carbon steel) 



Lead 



Magnesium 



Mercury 



Nickel 



Palladium 



Platinum 



Silver 



Tin 



Zinc 



Air 



Asbestos (loose) 



Brick (average fire) 



" ( " building) . . . 



Difiusivity. 



0.826 



•139 

 .0678 



•339 

 .467 



I-I33 

 1. 182 



0.173 

 .121 



•237 

 .883 

 .0327 

 .152 

 .240 

 •243 

 1737 

 0.407 

 .402 

 .179 

 .0035 

 .0074 

 .0050 



Material. 



Coal 



Concrete (cinder) 



" (stone) 



(light slag) . . . . 



Cork (ground) 



Ebonite 



Glass (ordinary) 



Granite 



Ice 



Limestone 



Marble (white) 



Paraffin 



Rock material (earth aver.) . . 

 " " (crustal rocks) . 



Sandstone 



Snow (fresh) 



Soil (clay or sand, slightly damp) 



Soil (very dry) 



Water 



Wood (pine, cross grain) . . 



" ( " with " ) . . 



Diffusivity. 



0.002 

 .0032 

 .0058 

 .006 

 .0017 

 .0010 

 .0057 



•0155 



.0112 



.0092 



.0090 



.00098 



.0118 



.0064 



•0133 



•0033 



.005 



.0031 



.0014 



.00068 



.0023 



Taken from "An Introduction to the Mathematical Theory of Heat Conduction," Ingersoll and Zobel, 1913. 

 Smithsonian Tables. 



