SOILS — FERTILIZERS. 213 



considered to bo the food bearers of the soil. Too much or too little of the 

 colloidal substances is said to impair the agricultural value of a soil. 



The possibility of judging soils by their natural vegetation on the basis 

 of the theory of probability, P. Vageler {Pflanzer, 9 {10 IS), No. 4, pp. 171-184; 

 abs. in Chem. ZenthL, 191S, II, No. 4, pp. 378, 37^).— From a mathematical 

 demonstration, based on the assumption that the quantitative relations be- 

 tween soil and plants depend primarily on the physical properties of the 

 soil, especially its hygroscopicity. it is concluded that the theory of probability 

 combined with rigorous adjustment of the errors of probability is applicable 

 for judging soils whose types of physical structure and plant forms lie within 

 certain extreme limits established by actual test. This method was tested using 

 hygroscopic values of some of the representative extreme soil formations of 

 German East Africa, having correspondingly distinct vegetation. 



It is concluded in general, from results obtained, that plant forms are regu- 

 lated by those physical properties of the soil which regulate the hygroscopic 

 water, and that under the same conditions of climate and with the same plant 

 forms the same soil properties will appear with a regularity which will vary 

 practically as indicated by the numerical probability error. It is further con- 

 cluded that this method not only places the judging of soils by their charac- 

 teristic vegetation on an exact numerical basis and reduces the number of 

 actual tests, but offers a useful method for tracing soils in open plain areas. 



Soil texture, C. T. Gimingham {Cliem. World, 2 {1913), No. 6, pp. 187, 188).— 

 The opinion is expressed that from all points of view the mechanical analysis 

 serves as a good basis for the classification of soils, but that the results of 

 such analysis can be of use only with a full knowledge of local conditions 

 since the textures of identical soil types often vary from field to field. In 

 this connection it is suggested that the percentage of shrinkage of soils on 

 drying be determine<l. 



White soil (Molkenboden), R. Hornberger {Internat. Mitt. Bodenk., 3 {1913). 

 No. 4, PP- 353-357). — The author reports his own and reviews other investiga- 

 tions on a rather impermeable grayish white soil, which he concludes is de- 

 rived from sandstone but is somewhat poorer in soluble potash and lime and 

 richer in phosphoric acid than an ordinary sandy loam derived from sandstone. 



Marsh, of the southern Vendee. — The influence of inundation on the fer- 

 tility, G. Chartron {B^a. Soc. Sci. Nat. Quest France, S. ser., 2 {1912), No. 

 3-4, pp. 125-132). — In discussing the fertility of the soils of these flats it is 

 stated that in the spring a kind of alga grows in the stagnant drainage water 

 on the flats, forming a slime coating on the soil after the water has disappeared 

 which is said to vary in amount from 214 to 1,158 lbs. per acre. Analyses of 

 samples show considerable nitrogen and lime but relatively little phosphoric 

 acid and potash. Analyses of soils from the surrounding slopes and of the 

 drainage water lead to the conclusion that the fertility of the swamp soils is 

 due more to the drainage water than to the slime. 



Preliminary report on the soils of the wine district of Arad-Hegyalja and 

 of the Arad plains, P. Treitz {Jahresbcr. K. Ungar. Geol. ReicJisnnst., 1910, 

 pp. 214-243). — A discussion of geology and meteorology in their relations to the 

 soil formations of these regions is followed by descriptions of the different types 

 of soil encountered in both hill and plains country. The soils of the hill coun- 

 try are divided into soils rich in humus and iron, calcareous soils, brown forest 

 soils, and podzol soils. The plain soils are discussed as sand and gravel soils, 

 light brown and dark brown desert soils, prairie clay, and alkaline soils. 



The soils of the rocky deserts of Turkestan, S. S. Neustruev (PochvovQ- 

 dQnie {PMologie), 15 {1913), No. 1, pp. 1-19). — This article discusses in some 

 detail the geological formations of the rocky deserts of Turkestan in their 



