266 REPORTS ON THE STATE OF SCIENCE, ETC. 



Geothermic Measurements in Wells. 



By D. Chahnazaroff. 

 Petroleos y Minas, Buenos Aires, vol. 13, no. 141, 1933, pp. 5-7. 



Geothermic measurements in wells can be made by various methods 

 depending on the purpose of observation. 



If a thermal survey, by which the thermic horizons of the well are to be 

 determined during one day, is required, an apparatus with automatic 

 registration of temperature should be used ; in this case the accuracy of 

 temperature obtained may be equal to 1 to i\° C. 



If an accuracy of J° to \° C. is desired, maximum thermometers or 

 open-tube thermometers without a graduation scale must be used ; the 

 latter are constructed on the principle that each drop of mercury which 

 flows out of the open end of the thermometer corresponds approximately 

 to \° C. ; the maximum thermometers are less convenient as more time 

 is required for carrying out the observations. If an accuracy equal to 

 T V C. is sought, the thermoelectric method, which is now sufficiently 

 improved, is rapid, and gives accurate results, should be applied. 



The Geothermic Gradient in Limagne. 



By G. Grenet. 



Comptes rendus de VAcaddmie des sciences, Paris, vol. 195, no. 25, December 5, 



1932, pp. iioo-iioi. 



A 200-metre boring was used for determining the geothermic gradient 

 at Macholles, near Riom. The temperature was measured at a depth of 

 192-2 m. The geothermic gradient was found to be equal to 14- 16 m./°C. 

 The result was in good agreement with the earlier observations at Macholles, 

 confirming the hypothesis that the geothermic degree over the greater part 

 of Limagne is of the order of 14 m./° C. 



On the Flow of Heat from a Rock Stratum in which Heat is being 



generated. 



By C. E. van Orstrand. 

 Journal of the Washington Academy of Sciences, Baltimore, vol. 22, nos. 20/21, 



1932, pp. 539-539- 

 A mathematical discussion of the question under the assumption that 

 the earth is a cooling globe and that the strata are parallel to the horizontal 

 surface of the ground is given. The results of calculations are represented 

 in curves and tables. 



Geothermal Gradient at Grass Valley, California. 



By W. D. Johnston, Jr. 



Journal of the Washington Academy of Sciences, Washington, vol. 22, no. 10, 



1932, pp. 267-271. 



Johnston gives in this article the results of temperature observations 

 carried out by him in the gold quartz mines at Grass Valley, California, 

 during 1930 and 1931. The depth-temperature curve, shown in a figure, 

 is slightly concave toward the depth axis. Temperature gradients at the 



