2l6 



TABLES 233-234. 

 CONDUCTIVITY FOR HEAT. 



TABLE 233. Various Substances. 



kt is the heat in gram-calories flowing in i sec. through a plate I 

 drop in temperature. 



cm. thick per sq. cm. for iC 



Substance. 



Asbestos fiber .... 

 85% magnesia asbestos . 

 Cotton . . 



Eiderdown 



Lampblack, Cabot number 5 

 Quartz, mesh 200 .... 

 Poplox, popped Na 2 SiO 3 . 

 Wool fibers . 



Density, 



0.201 

 .216 



.021 

 .IOI 

 .0021 

 .109 



193 

 1.05 

 0.093 



.015 

 .054 

 .192 



500 



100 



500 



100 



500 

 500 

 200 

 500 



.00019 

 .00016 

 .00017 



.000111 



.000071 

 .00015 

 .000046 



.000074 



.000107 



.00024 



.000091 



.000160 



.000118 



.000085 



.000054 



Substance. 



Asbestos paper . . 

 Blotting paper . . . 

 Portland cement . . 

 Cork, t,oC . . . 



Chalk 



Ebonite, t, 49 . . . 

 Glass, 'mean . . . 

 Ice. ...... 



Leather, cow-hide 

 " chamois . . 



Linen 



Silk ....... 



Caen stone, limestone 

 Free stone, sandstone 



0.00043 

 .00015 

 .00071 

 .0007? 



.0020 



.00037 



.002 



.0057 



.00042 



.00015 



.OOO2I 



.000095 



.0043 



.0021 



Authority. 



Lees-Chorl- 

 ton. 



Forbes. 

 \ H, L, D, 

 J see p. 205. 



Various. 



Neumann. 



I Lees-Chorl- 

 ton. 



[ H, L, D. 



Left-hand half of table from Randolph, Tr. Am. Electroch. Soc. XXI ., p. 550, 1912 ; k t (Randolph's values) 

 is mean conductivity between given temperature and about ioC. Note effect of compression (density). The 

 following are from Barratt Proc. Phys. Soc., London, 27, 81, 1914- 



Substance. 



Brick, fire . 

 Carbon, gas 

 Ebonite . . 

 Fiber, red 

 Glass, soda 

 Silica, fused . 



Density. 



'73 

 1.42 

 1.19 

 1.29 

 2.59 

 2.17 



at 2oC. at iooC. 



.00110 



.0085 

 .00014 



.00112 



.00172 



00237 



.00109 



.0095 



.00013 

 .00119 

 .00182 



.00255 



Substance. 



Boxwood . 



Greenheart 



Lignumvitae 



Mahogany 



Oak. . . 



Whitewood 



Density. 



0.90 

 1.08 

 1.16 

 -55 

 0.65 

 0.58 



at 2oC. at iooC. 



.00036 



.00112 

 .OOO6O 

 .00051 

 .00058 

 .00041 



.00041 

 .00110 



.00072 

 .00060 

 .00061 



.00045 



The following values are from unpublished data furnished by C. E. Skinner of the Westinghouse Co., Pitts- 

 burgh, Penn. They give the mean conductivity in gram-calories per sec. per cm. cube per C. when the mean 



temperature of the cube is that stated in the table. Resistance in thermal ohms (watts/inch 2 /inch/C.) = 



10.6 



conductivity. 



Substance. 



Grams, 

 per cm 3 . 



Conductivity. 



00 C. 200 C. 300 C. 400 C. 500 C 



Safe 

 temp. 



Air-cell asbestos 



Cork, ground 



Diatomit 



Infusorial earth, natural . 



" " h'd pressed blocks 

 Magnesium carbonate .... 

 Vitnbestos 



0.232 

 .168 

 .326 

 .506 

 .321 

 450 

 .362 



0.00034 

 .00015 

 .00028 

 .00034 

 .00030 

 .00023 

 .00049 



0.00043 

 .00019 

 .00032 

 .00032 

 .00029 

 .00025 

 .00066 



0.00050 



.00037 

 .00040 

 .00033 

 .00025 

 .00079 



0.00042 

 .00036 

 .00090 



0.00046 



320 

 i Ho 

 6cx) 



400 

 300 

 600 



TABLE 234. Water and Salt Solutions. 



SMITHSONIAN TABLES. 



