620 EXPERIMENT STATION EECOED. 



aluminum liydrosid. Tlae silicic acid in the presence of a basic reaction of the 

 soil, which results from a deficiency of organic matter under the influence of 

 the laterite decomposition and high temperature of the soil, is unusually stable 

 and does not undergo coagulation, but is washed out with water along with the 

 alkalis. On the other hand, the aluminum hydroxid and ferric oxid are vex-y 

 unstable under these conditions and are quickly coagulated and thus fixed in 

 the soil. The determining factors, therefore, in the formation of laterite soils 

 under tropical climatic conditions are high temperature and rapid decomposi- 

 tion of the organic matter. 



The condensation of water vapor in the soil, E. Makchenko {Dnevn. XII. 

 8"{ezda Riiss. Est.-Is}}. i Vracli. [Moscoio], 1910, No. 8, pp. SJtO, 3^1; abs. in 

 Qeol. Zentbl., U (1910), No. 8, p. 512; Wasser u. Abwasser, 3 (1910), No. 6. 

 p. 235). — The author maintains that water vapor may be condensed to ground 

 water in the soil. 



Influence of woods on the temperature of the soil and subsoil, N. Nesterov 

 (Liesoprom. VfestniJc, 1909, No. 16, pp. 153-158; abs. in Zhur. Opytn. Agron. 

 (Ritss. Jour. Expt. LanchD.), 11 (1910), No. 3, p. 4O8). — Observations on the 

 temperature of the water in wells bored in woods and in clearings at the 

 Moscow Agricultural Institute showed that (1) the temperature of the subsoil 

 under the forest was throughout the entire year lower than under the open 

 ground, (2) the influence of the forest in lowering the temperature of the sub- 

 soil was noticeable to a depth of 10 meters, (3) the rate of cooling of the sub- 

 soil was slower under the forest than outside of the forest, and (4) on a new 

 clearing the subsoil warmed up during the summer to a depth of only 3 meters, 

 reaching a temperature corresponding to that of open land. 



The relation of colloidal silica to certain impermeable soils, K. F. Keller- 

 man (Science, n. ser., 33 (1911), No. 8.'i0, pp. 189, 190). — Investigations are 

 briefly reported which indicate that the impermeability of certain soils of the 

 Truckee-Carson Irrigation Project is due to the presence of considerable 

 amounts of colloidal silica. The addition of calcium sulphate improved the 

 permeability of the soils, apparently by coagulating the colloidal silica. 



The role of mica in cultivated soil (Rev. 8ci. [Paris], ^9 (1911), I, No. 3, 

 p. 83). — The investigations of Prianishnikov (E. S. R., 17, p. 842) and Bieler- 

 Chatelan (E. S. R., 23. p. 715) are briefly noted as showing that mica (mus- 

 covite) is capable of furnishing more potash to plants than feldspar (ortho- 

 clase). This is attributed to the higher solubility of the former mineral, the 

 solubility being increased by the use of gypsum, peat, ammonium sulphate, 

 quicklime, monocalcium phosphate, and other substances. 



Increase in nitrates in limed as compared with unlimed soils, J. de Vee- 

 TEUiL (Bui. Dept. Agr. Trinidad, 9 (1910), No. 66, pp. 239, 2// 0).— Examination 

 of two limed soils showed a striking increase in percentage of nitrates over 

 the unlimed soils. 



On the action of crushed quartz upon nitrate solutions, H. E. Patten 

 (Jour. Phys. Chem., I4 (1910), No. 7, pp. 612-619, fig. 1; abs. in Ohem. Abs., 5 

 (1911), No. 2, p. 3Ji5). — Experiments are reported which indicate that silver 

 nitrate is reduced to a slight extent by flltration through pure sterile quartz, 

 but that nitrate of soda is not so reduced. It is therefore concluded that the 

 reduction of nitrate which occurs in the soil is probably due to bacterial 

 agencies and to inorganic and organic chemical reactions rather than to the 

 catalytic surface effect of the soil grains. 



Investigations and observations on the behavior of different kinds of 

 humus, C. Emeis (Allg. Forst v. Jagd Ztg., 86 (1910), Dec, pp. 425--i32).— 

 This article briefly reviews investigations on the formation of nitrates and of 

 so-called humus acids and their combinations with the mineral constituents of 



