THERMAL CONDUCTIVITIES OF ROCKS 261 



Geothermal Measurements in the City of Moscow (in Russian). 



By S. Kraskovski. 



Transactions of the Central Geological and Prospecting Institute, Leningrad, 



no. 8, 1934, pp. 45-51. 



Geothermal measurements in two artesian boreholes on the territory of 

 the City of Moscow were made by the author from July 15 to September 1, 

 1932. The purpose of these measurements was to find the approximate 

 value of the geothermal degree and to elucidate the influence of casings on 

 the distribution of temperature along the vertical line of the borehole. The 

 results of measurements have shown that one single column of casings does 

 not produce a marked influence on the distribution of temperature. 



A value equal to 38-4 m./°C. was obtained for the geothermal degree. 

 This figure is below the normal value and may be explained by the cooling 

 influence of a water-bearing horizon found at a depth of 721 m. 



Normal Geothermal Gradient in United States. 



By C. E. van Orstrand. 



Bulletin of the American Association of Petroleum Geologists, Tulsa, Okla., 

 vol. 19, no. 1, 1934, pp. 78-115. 



The objects in compiling this paper have been, first, to prepare a brief 

 summary of the gradients deduced from recent geothermal surveys in the 

 United States ; and second, to discuss the data thus summarised from the 

 standpoint of a normal geothermal gradient. 



The Thermocouple proves useful on a Geophysical Survey. 



by j. n. a. van den bouwhuijsen. 

 Engineering and Mining Journal, New York, vol. 135, no. 8, 1934, pp. 342- 



344- 



The flow of heat from the earth's centre toward a fixed point close to its 

 surface depends on the heat conductivity of the rock formations between 

 the centre and the point and on the thickness of the different layers. There- 

 fore, according to the author, a shift in the location and a variation in the 

 thickness of the layers would result in differences in temperature when 

 measured across the structure at the same depth. 



Thus the horizontal gradient of the temperature in a layer close to the 

 surface should supply some evidence as to the structure of the underlying 

 formations. To prevent the influence of the variations of the atmospheric 

 temperature it is sufficient to measure the temperature at a depth of 1*5 m. 

 Holes drilled for the measurements were about i£ inches in diameter. 



The experiments were made with thermocouples of special construction, 

 connected to a galvanometer of high sensitivity and sturdy enough to stand 

 transportation in the field. 



To determine the value of the new method (thermo-electric method) the 

 author made experiments over two profiles which had previously been well 

 determined by torsion-balance work by Mekel, near Winterswijk, Holland. 

 The results agreed most remarkably with those got by the gravity method. 

 Plans showing the results of temperature measurements and of torsion 

 balance survey are given. 



Approximately $200 would buy all of the instruments. The reading 



