118 EXPERIMENT STATION RECORD. 



central collectiug pit there is placed a receptacle into \A-liicli the drainage waters 

 of the tanks are discharged. Connected with these receiving tanks is an over- 

 flow tank, to be used in case of emergency, as from long-continued heavy rains. 

 The collectiug pit, which is about 8 ft. deep and G ft. square, is built of brick 

 with a concrete bottom, and is covered. 



The tanks were sunk into the ground to within a few inches of the top and 

 filled with soil to within 3 in. of the edge. The sloping part of the bottom was 

 covered with a layer of smooth quartz pebbles, the coarsest material being 

 placed around the drainage opening. The soil dug from the site which each 

 tank was to occupy was divided into four lots, the top 9 in. forming the first 

 lot, followed by 3 one-foot sections. In filling the tanks the last foot taken 

 from the ground was placed on the gravel in the bottom of the tank, then the 

 next foot was taken, and so on to the top 9 in. The soil was well tamped, each 

 tank containing 8.625 lbs. of dry soil. One orange tree was planted in each 

 tank. 



On the influence of shade on the evaporation of water from the soil, C. 

 voN Seelhorst {Jour. Landw., 58 {1010), No. 3, pp. 221-228). — Results of ob- 

 servations comriariug the evaporation from a loam soil shaded with dry rye 

 plants, and the same type of soil unshaded, show that the shaded soil evaporated 

 13.9 per cent less of the rainfall than the unshaded soil. 



The value of pyritic moor soils as a foundation for drainage structures, 

 G. Fendleb and L. Frank {Gsndhts. Ingeri., 33 {1910), No. 49, pp. 877, 878).— 

 In view of the fact that injuy to drainage structures at Osuabriick had been 

 attributed to the presence of free sulphuric acid in water derived from a moor 

 containing pyrites and the belief that such conditions are more or less general, 

 the author made a series of examinations of samples of water from a moor of 

 this character. He failed to find free sulphuric acid present, the analyses show- 

 ing the presence of a sufficient amount of carbonates to exclude the possibility 

 of formation of free sulphuric acid. 



On the plasticity of clay soils, J. M. Van Bemmelen {Chem. Weekbl., 7 

 {1910), No. 37, pp. 793-805). — This article summarizes present knowledge re- 

 garding the absorption of water by clay, the swelling and shrinking of clay, the 

 formation of colloids in clay by the action of acids and alkalis, the structure of 

 clay, and chemical action in clay soils of varying structure, and discusses va- 

 rious theories of plasticity. 



Soil organic matter as material for biochemical investigation, O. Schrei- 

 ner and E. C. Shobey {Jour. Franklin Inst., 171 {1911), No<. 3, pp. 295-300; 

 ahs. in Science, n. scr., 33 {1911), No. 8U, PP- 339, 3.'/0).— This article empha- 

 sizes the importance of an exact knowledge of the composition of the organic 

 matter of the soil and describes in outline the methods pursued by the Bureau 

 of Soils of this Department in separating the organic compounds of the soil. 

 See also a previous note (E. S. R., 24, p. 301). 



Cholesterol bodies in soils: Phytosterol, O. Schreineb and E. C. Shorev 

 {Jour. Biol. Chcm., 9 {1911). No. 1, pp. 0-11, pi. 1). — This work has been pre- 

 viously noted (E. S. R., 24, p. 301), but is here discussed in a more extended 

 manner. 



Oxidation in soil, M. X. Sullivan and F. R. Reid {Jour. Indvs. and Engin. 

 Chem., 3 {1911), No. 1 pp. 25-30; Chem. News, 103 {1911), Nos. 2673, pp. 73- 

 75; 267 Ii, pp. 88, 89). — The authors describe a method of testing oxidation in 

 soils by means of changes produced in easily oxidizable substances, such as 

 aloin, when brought in contact with the soil, and report investigations on the 

 effects of various factors and treatments on soil oxidation. It is believed that 

 the study of oxidation in soil has considerable value in relation to soil fertility, 



