S16 EXPERIMENT STATlOlST RECORD. 



(wattpolder) soils formed by the action of tlie ebb and flood of the tide. The 

 author believes that the fine, suspended (schlick) particles which are observed 

 in the shoal water on the beaches where the polders form are derived mainly 

 from the excrement of a sand worm {Arenicola piscatorum) that feeds upon 

 the sands of the beaches. 



Results of pot experiments with oats showed that the sand, very poor in 

 plant food, is rendered comparatively fertile upon passing through the body of 

 the worm. 



Black soil and lime crusts in Morocco, T. Fischer (Ztschr. Prakt. Geol., IS 

 il'JlO), No. 3, PI). 105-11-',; ahs. in Chcm. Zcnthh, 1910, I, No. 2J,, p. 1985).— It 

 is stated that this soil, which is widely distributed in Morocco, is very pro- 

 ductive with aimual plants but does not support tree growth ovping to its shal- 

 lowness and the scarcity of rainfall during the summer months. Results of 

 microscopic examination show the soil to contain a large number of small 

 mineral particles foreign to the underlying rock strata. The author believes 

 that the soil contains eolian deposits, the sand particles being carried by the 

 wind and deposited where vegetation and moisture tend to hold them in place. 

 A high water-holding capacity and high organic matter content are important 

 characteristics of the soil. 



Investig'ations on the black soil of Morocco, A. Schwantke {Ztschr. Prakt. 

 Geol., IS (1910), No. 3, pp. lVt-119; ahs. in Chcm. Zenthl., 1910, I, No. 24, p. 

 1985). — Results of microscopical and chemical investigations strengthen the 

 views held by Fischer (noted above) regarding the eolian origin of these soils. 



The mechanical analysis of soils of Java, E. C. J. Mohr (Bill. D6pt. Agr. 

 Indes N6erland., 1910, No. J,!, pp. 33, pi. 1; Teysmannia, 21 {1910), No. 7, pp. 

 l/55~Jf71, 2)ls. 3). — The author calls attention to the fact that on account of 

 the rapid changes which go on in soils in tropical countries like Java, me- 

 chanical analysis at any given time is of less value than in case of soils of 

 temperate regions, and it is more necessary to follow closely the changes going 

 on in the soil. 



The methods -used (based to a large extent on those of the Bureau of Soils 

 of this Department) are described, as well as methods of stating and interpret- 

 ing the results of mechanical analysis. A grai)hic classification by means of an 

 equilateral triangle, the three points of which are sand >50,ti, silt 50-5/li, and 

 clay< 5^1, is explained. 



The author's results indicate that mechanical analysis does not always furnish 

 a basis for an exact classification of soils. He is of the opinion that determi- 

 nation of hygroscopicity as proposed by INIitscherlich is often a simpler and, for 

 practical purposes, a better method of classifying soils, although it can ne\er 

 entirely take the place of careful mechanical analysis in the investigation of 

 soils. 



Soil waters, J. B. Harrison and F. A. Stockdale (Rpt. Expt. Agr. Work 

 Dept. Sci. and Agr. [Brit. Guiana], 190S-9, pp. 16-21). — This is a report of a 

 continuation of the study of the composition of soil and subsoil and under- 

 ground waters on the experimental farm of Demerara at Georgetown, showing 

 that there was a great increase in ammoniacal nitrogen and decrease in nitric 

 acid in the soil water of a wet season as compai'ed with a dry season. 



Water taken from a depth of 12 ft. from an exceedingly fine grained sand 

 called " caddy " showed a relatively high ijroportion of nitrogen present in the 

 form of ammonia and of organic matters with a relatively low proportion as 

 nitrates. 



A soil of low fertility showed a high proportion of ma.gnesium to calcium in 

 both the clay and sand, the molecular ratio in the former being 1 of calcium to 

 6.6 of magnesium, and that of the sand 1 of calcium to 7.08 of magnesium. 



