AIR WATER — SOILS. 421 



leguminous crops upon the lands and plowing them under as green manuring. So 

 far as now known alfalfa and crimson clover arc the best of these, and their use for 

 this purpose is undoubtedly an essential part of any scheme of crop rotation for this 

 region." 



Materials for the study of Russian soils, XI, A. Sovyetov and 

 N. Adamov (St. Petersburg, 1898, pp. 221; abs. in Selslc. Khoz.i Lyesov., 

 189 (1898), June, pp. 711, 712). — This part contains, among- others, the 

 following articles: The influence of the electrization of the soil on the 

 processes which take place in it, by S. Kravkov; the assimilation by 

 plants of the nitrogen of the soil a-< dependent upon meteorological 

 conditions, by A. Doyarenko; and the absorbing power for phosphoric 

 acid of some Russian soils, by V. Krat. 



The first article gives, besides a brief review of literature on tiie ques- 

 tion of electrocnltnre, the results of the author's laboratory investiga- 

 tions relating to the study of the physical and chemical properties of 

 the soil subjected to electrization. The following are the results arrived 

 at: A galvanic current passed through the soil produces a marked 

 influence on many chemical and physical processes taking place in it. 

 First of all its action is shown in an intensified decomposition of the 

 organic matter in the soil, causing the formation of au excess of carbon 

 dioxid, which in its turn acts as a solvent on the constituents of the soil. 

 The increased concentration of the soil solution in its turn (1) decreases 

 the intensity of the evaporation of water by the soil ; (2) reduces greatly 

 the capillary power of the soil; (3) lowers to the minimum its percolat- 

 ing capacity; and (4) somewhat alters the character of the structure of 

 the soil, rendering it larger grained. In general, according to the 

 author, the protracted action of the galvanic current may reduce cher- 

 nozem soils to great poverty in humus and lead to complete exhaustion. 



The second article gives the results of experiments by the author 

 with winter wheat, which established the dependence of the assimila- 

 tion of nitrogen on atmospheric precipitation (in dry weather less nitro- 

 gen is assimilated than in rainy weather), as well as a similar connection 

 between this process and the temperature, humidity, and sometimes 

 the barometric pressure. — p. fireman. 



Composition of Indian soils, J. W. Leather (Ayr. Ledger {Ayr. 

 ser., To. 24), 1898, No. 2, pp. 83). — According to the author four main 

 types of soils occupy by far the greater part of the cultivated area of 

 India. These are u the Indo Gangetic and other alluvium, the black 

 cotton soil or reyur, the red soils lying on the metamorphic rocks of 

 Madras, and the laterite soils which are met with in many parts of 

 India. There are doubtless other minor classes of soils, but they neither 

 possess such characteristic differences in appearance, nor are they dis- 

 tributed over such extensive areas as the 4 types referred to." Chem- 

 ical analyses, descriptions, etc., are given of 2'2 samples of the first 

 class, 18 of the second. 7 of the third, and 12 of the fourth, besides of 

 6 samples of coffee soils from Madras, 4 of tea garden soils (with sub- 

 soils) from the Dooars, 9 of bhil or peaty tea soils, and 3 of teela or poor 



