88 abstracts: mineralogy 



AGRICULTURAL CHEMISTRY.— The effect of moisture and of solu- 

 tions upon the electric conductivity of soils. R. O. E. Davis. Trans- 

 actions of the American Electrochemical Society, 17: 391-403. 1911. 



Experiments on the conductivity of several types of soil under various 

 conditions are described. The relation of conductivity of a soil to the 

 corrosion of iron is pointed out. From the measurements of soil resistiv- 

 ity the conclusions are drawn: (1) That in the dry condition the soil 

 offers a high resistance to the passage of the electric current. (2) That 

 at a depth of two feet or more the conductivity remains roughly con- 

 stant for a given soil type and soil area. (3) That the conductivity 

 of soils saturated with water increases directly as the amount of salt in 

 solution increases; below saturation, the resistivity increases almost 

 in proportion to the surface area of the soil, at saturation and beyond, 

 the surface area does not exert so much influence. (4) That humus 

 decreases the conductivity of a soil. 



A sandy soil will probably afford least electrolyte, and clay soil most, 

 due mainly to the state of physical division of the soil. It would be pos- 

 sible to roughly calculate the electrolysis produced by a given potential 

 difference between two points in the soil. R. O. E. D. 



MINERALOGY. — Die chemische Zusammensetzung von Jamesonit und 

 Warrenit. W. T. Schaller. Zeitschr. Kryst. Mineral, 49: 562- 

 565. 1911. 



From a review of the literature it is concluded that the formula for 

 jamesonite is 4PbS.FeS.3Sb 2 S> while warrenite is a mixture of jamesonite 

 and zinckenite. W. T. S. 



MINERALOGY. — An occurrence of struverite. Frank L. Hess and 

 R. C. Wells. American Chemical Journal, 31: 432-442. 1911. 



The mineral here designated struverite is one of a series containing 

 Ti 2 , Fe 0, Ta 2 5 and Cb 2 5 , in variable proportions. At one end 

 of the series is a group to which the name ilmenorutile is given, in 

 which Cb 2 5 exceeds Ta 2 5 . At the other end of the series is a group 

 in which the Ta 2 O5 exceeds the Cb 2 5 and of which the mineral de- 

 scribed in the paper is the only representative known. In 1908 Prior 

 and Zambonini 1 described a mineral with a nearly medial composition, 

 which they called struverite, and defined in such a way as to include 



MDn struverite and its relation to ilmenorutile. Mineralog. Mag., 15: 78-89. 190S. 



