234 EXPERIMENT STATION RECORD. 



rocks and rock-fonning minerals, the work must l>e considered in no sense a petrology 

 as this word is commonly used. What is here given relative to the origin, structure, 

 and composition of rock masses is regarded as an essential introduction to the chap- 

 ters on rock-weathering." 



The hook is divided into five parts as follows: (1) The constituents, physical and 

 chemical properties, and mode of occurrence of rocks; (2) kinds of rocks; (3) the 

 weathering of rocks; (4 ) transportation and redeposition of rock debris, and (5) 

 the "regolith." The plan of treatment is simple and natural, and leads the reader 

 easily from a consideration of the original rocks through the various stages of their 

 disintegration and decomposition, and the transportation of rock debris to the 

 formation and characteristics of soils. 



In the part dealing with weathering the action of the atmosphere, chemical action 

 of wafer; the mechanical action of water and ice; and the action of plants and 

 animals, including nitrifying organisms, are discussed in detail. A valuable 

 feature of the work is a special chapter based largely npon original work by the 

 author on the chemical and microscopical character of the material resulting from 

 the weathering of rocks in place. This work is especially valuable in bringing out 

 the changes in composition which the material of soils has undergone in the pro- 

 cesses of weathering and leaching. 



The most important chapter from the agricultural standpoint is that devoted to 

 "regolith." This term is used to include not only the soil, subsoil, and residual 

 products of decomposition, but also the alluvial, seolian, and glacial deposits. The 

 petrographical characters and conditions of the formation of the various deposits 

 included in the regolith are described and the chemical nature, mineral composition, 

 physical condition, weight, kinds and classification, color, and age of soils are briefiy 

 discussed, as well as the effect of plant and animal life on soils. 



It is believed that this work will prove of great value to agricultural students and 

 investigators because it is both comprehensive and suggestive, and treats many 

 phases of the subject of the origin, formation, and characteristics of soil, especially 

 the character, processes, and results of weathering, which have heretofore been 

 more or less neglected; and lays a solid foundation for special studies and treatises 

 on the soil in its agricultural relations. For an interesting review of the work see 

 Nature, 56 (1897), No. 1440, pp. 97, :>S. 



The cultivation of the soil, P. P. Deherain (Ann. Agron., 23 (1897), No. 5, pp. 

 216-229). — Second paper. 



The relation between the underground and the cultivated soil, A. Helland 

 (Tidsslr. norske Landbr., 4 (1897), pp. 145-101). 



On subsoil plowing, G. Grotexi ei.t (Om Alfplojning. Mustiala (Finland), 1895, 

 pp. 10). 



FERTILIZERS. 



Experiments with fertilizers (Selsk. Khoz. Lyesov., 183 (1896), pp. 

 1229-1231). — The object of these experiments was to determine the 

 influence of lupines grown with artificial fertilizers and plowed under 

 as green manure on the yield of wheat. The experiments were carried 

 out on plats of 172^ square yards each, tests of each fertilizer combi- 

 nation being made in duplicate. The fertilizers were applied in amounts 

 furnishing 53 lbs. of potash, 35.5 of phosphoric acid, and 53 of nitrogen 

 per acre. The lupines were planted May 5 and plowed under August 5. 

 Wheat was sowed September 2. The quantity of green manure plowed 

 under was determined by weighing the lupines (tops and roots) on a 

 plat of the same size as those used in the experiments (172£ square 

 yards). The yield of green lupines varied from 34,974.65 lbs. to 

 38,529.39 lbs. per acre. 



