272 REPORTS ON THE STATE OF SCIENCE, ETC. 



from this. — Melting curves according to Wolff ; curves showing the cooling 

 of spherical bodies of various substances representing the earth, in one 

 million years, starting with a temperature of ioo°, according to van Orstrand ; 

 and curves of the temperature inside the earth's crust according to Jeffreys, 

 Adams, Wolff, and Gutenberg are given. 



10. The temperature of the earth's crust based on statical observations. — 

 As a final conclusion the author gives the following probable figures for the 

 temperatures inside of the earth : 



Depth, km. . . 20 100 200 500 6,370 



Temperature . 6oo° 1,400° i,6oo° i,8oo° 2,000-5,000° 



Geothermal Method of Prospecting. 



By C. L. Alexanian. 



Extract from Traite pratique de prospection ge'ophysique (Practical treatise on 

 geophysical prospecting), by C. L. Alexanian. Librairie Polytechnique 

 Ch. Beranger, 15 Rue des Saints-Peres, Paris, 6. 



Values of geothermal gradients are given by the author for the following 

 countries : 



Metres 

 67 

 25 

 14 

 14 to 21 



14 

 7 



According to Koenigsberger the normal geothermal gradient in case of 

 horizontal layers is about 34 m./° C. This value varies greatly in case of 

 inclined or vertical layers. 



The possible reasons for the great local anomalies of the geothermal 

 gradient are given by Alexanian as caused by : 



1. Deposits originated by heat processes or of volcanic origin. 



2. The distribution of heat due to the displacement of various substances 

 in the earth's crust, such as hot springs, mineral waters, and gas. 



3. Deposits produced by heat caused by chemical reactions or deposits 

 containing radioactive substances. 



4. Thermal conductivity of rocks and tectonic displacements (heat 

 produced by friction). 



A list of thermal conductivities of rocks is given. 



The last two paragraphs of the article contain a brief description of 

 methods for measuring the temperature of the soil and a method for 

 calculating the temperature gradient. 



Geothermal Variations in Coalinga Area, Fresno County, 



California. 



By Anders J. Carlson. 



Bulletin of the American Association of Petroleum Geologists, Houston, Tex., 

 vol. 15, no. 7, 1931, pp. 829-836. 



Variations of isothermal elevations with respect to structure are developed 

 from temperature measurements in fifty-six wells of the Coalinga area. 



Pribram (Czechoslovakia) 



Sabountchy (oil region near Baku, U.S.S.R.) 



Machfilles (Limagne) 



Pechelbronn (Alsace) 



Los Angeles (California) 



Kutzenhausen (Alsace) 



