986 



EXPLORATION GEOPHYSICS 



parts — for a non-radioactive earth, and for a radioactive earth. The results of the two 

 parts are then combined for final calculation.f An article by UrryJ offers excellent 

 reference to work along this line. The problem is not simple and the calculations are 

 laborious. The interested reader is referred to the literature for details. 



TABLE 26 

 THERMAL CONDUCTIVITY CONSTANTS* IN C.G.S. UNITS 



Material Conductivity Material 



Air (0°C.) 0.00005-0.00006 



Calcite 0.005 -0.015 



Coal 0.0003 -0.0008 



Clay (dry) 0.002 - 0.003 



Clay (moist) 0.003 -0.004 



Feldspar 0.005 



Gneiss 0.005 -0.006 



Granite (100°C.) 0.004 -0.008 



Graphite 0.01 -0.02 



Gypsum 0.002 -0.004 



Ice 0.002 -0.006 



Lava 0.002 -0.005 



Lime 0.0003 -0.006 



Limestone 0.005 -0.008 



Marble 0.005 -0.007 



Mica 0.0009 -0.0018 



Paraffin 0.00023 - 0.00061 



Conductivity 



Petroleum 0.003 - 0.004 



Porphyry 0.005 -0.008 



Rock Salt 0.006 -0.007 



Sand (very dry) 0.0008 - 0.0009 



Sand (about 10% 



moisture) 0.002 - 0.003 



Sand, Quartz (dry) . . .0.001 - 0.003 



Sand, Quartz (moist) . .0.008 - 0.009 



Sandstone (dry) 0.002 - 0.003 



Sandstone (moist) 0.005 - 0.007 



Slate 0.0047 -0.0057 



Snow (fresh) 0.0003 -0.0005 



Soil (clay or sand, 



slightly damp) 0.003 -0.004 



Soil 0.0003 -0.0009 



Water 0.0014 



THERMAL METHODS 

 UNITED STATES PATENTS 



2,245,700 Issued June 17, 1941. W. D. Mounce. "Resistance Thermometer." 

 2,318,601 Issued May 11, 1943. F. C. Doble. "Electrical Means for Indicating Tem- 

 perature Conditions." 

 2,365,706 Issued Dec. 26, 1944. G. Keinath. "Temperature Compensated Condition 



Response Measuring System." 

 2,375,892 Issued May 15, 1945. G. Bouyoucos. "Thermometer." 



2,393,197 Issued Jan. 15, 1946. R. Scott. "Remote Reading Temperature Instrument." 

 2,395,192 Issued Feb. 19, 1946. R. H. Ostergren. "Resistance Thermometer." 

 2,396,724 Issued March 19, 1946. A. F. Spilhaus. "Bathythermograph and Sea 



Sampler." 

 2,412,564 Issued Dec. 17, 1946. F. L. Current. "Heat Measuring Apparatus." 

 2,437,085 Issued March 2, 1948. J. Evans. "Heat Detection Device." 



t C. E. Van Qrstrand, "Geothermal Methods of Estimating the Age of the Earth," Geophysics, 

 Vol. V, No. 1, Jan., 1940, pp. 57-79. 



% Wm. D. Urry, "Thermal History of the Earth," Trans. Am. Geophys. Union, Vol. 30, No. 2, 

 April, 1949, pp. 171-180. 



* Taken from various sources in the literature. 



