THERMAL CONDUCTIVITIES OF ROCKS 259 



Basalts, etc. 



Scotland, Ireland, N. America : Ra 0-96 ± 0-06 ; Th 0-98 ± 0-08. 



England, Germany, France, Hungary: Ra 1 30 ± 013 ; Tho-88 ± o-io. 



Pacific Islands: Ra 0-90 ± 003 ; Th 0-46 ±0-03. 

 Plateau Basalts. Rao-73 ±0-03; Tho*52 ±002. 

 Dunites. Rao-4o ±0-043; Th.033 ±0-035. 



Eclogites and peridotites, in comparison with the mean, are as variable 

 as granites, or more so. 



The results are consistent with granites and basalts being successive 

 stages in differentiation from plateau basalt or something still more basic ; 

 but the variability of eclogites and the origin of the known dunites are 

 inconsistent with these rocks being actual specimens of such a parent. 



The granites from Cornwall and Hungary are intermediate between the 

 Scottish and Finnish types. The mean radioactivity of the granitic layer 

 is therefore open to considerable doubt ; reasons are given in the paper for 

 provisionally preferring the Scottish value. 



REVIEW OF LITERATURE ON GEOTHERMAL METHODS. 



Compiled by Dr. D. W. Phillips, from the Geophysical Abstracts, 

 U.S. Bureau of Mines, to whom acknowledgment is due. 



Geothermal Measurements in the Boreholes (in Russian). 

 By S. Kraskovski. 



Transactions of the Central Geological and Prospecting Institute, Leningrad, 



no. 8, 1934, pp. 1-43. 



In the first chapter the author states in chronological order the results of 

 geothermal measurements in boreholes in Europe, beginning with Erman's 

 investigations (dated 1832). Describing further the results of experiments 

 in boreholes Paruschowitz V and Chuchow (Upper Silesia) he dwells upon 

 Dunker's investigations (1896) and a compendium of all former observations 

 on the subject by Prestwich (1884-85 and 1895). Concerning the measure- 

 ments of temperature in the upper strata of the earth's crust J. Koenigs- 

 berger's works are particularly valuable. He was the first to draw 

 attention to the great practical importance of geothermal measurements ; 

 he had such material based on facts and arranged it so that the relationship 

 between the magnitude of the geothermal degree and the geology of the 

 region under investigation became obvious. 



An excellent example of this kind is given by the reports of the American 

 investigators, especially by C. E. van Orstrand, whose works are mentioned 

 in the article. Data obtained by the American Petroleum Institute and 

 interpreted by K. Heald deserve also special attention. 



In making thermal maps of the region under investigation van Orstrand 

 applied, probably for the first time, the graphic method to elucidate the 

 relation existing between the reciprocal gradient and geological structures. 

 At present we already may in some cases contour a stock of salt or an occur- 

 rence of petroleum by geothermal measurements. Of great interest are 

 the investigations in the United States showing anticlinal structure of the 

 oil-fields. 



Instruments and apparatus adapted for geothermal measurements in 

 deep borings are described in the third chapter. The fourth contains a 

 detailed description of methods of measurement and enumerates a number 



