SOILS FERTILIZERS. 221 



forations, was laid in the bottom of the soil tank to insure an uninterrupted 

 and well distributed feeding of water from the reservoir tank into the super- 

 imposed soil. As soon as the material became saturated and capillary action 

 established to the surface, the water level in the soil was brought to the de- 

 sired depth and kept there by supplying water to the reservoir tank in meas- 

 ured quantities. Volumetric measurements of water poured into or withdrawn 

 from the reservoir tank were made with an ordinary gallon measure. Accumu- 

 lation or depletion of the supply in the reservoir tank was determined volu- 

 metrically by measuring the depth of water with a steel tape. The volume pass- 

 ing out of the reservoir tank during a given period represents the total evapora- 

 tion from the soil tank during that period." 



From the results of these studies the author concludes that the relation be- 

 tween soil evaporation imder arid conditions and ground water fluctuation is 

 one of cause and effect. The diites of maxima for the one correspond to the 

 dates of minima for the other. 



It is suggested therefore that the dissipation of ground water into the 

 atmosphere can be prevented " by providing some means by which the sur- 

 face of saturation can be kept at or below the limiting depth at which soil 

 evaporation will occur. The loss will then cease, and the means by which it 

 is ■accomplished, whether by pumped wells or deep drainage ditches, will deliver 

 an equivalent volume of water that can be put to beneficial use. The con- 

 centration of alkali in the upper soil layers which usually accompanies rising 

 ground waters would also be under control and the drained land fitted for 

 agricultural purposes. There is yet much to be done in this direction before 

 complete use can be made of the available water supply of the Western States." 



A new method of physical analysis of the soil, J. Dumont (Cnmpt. Rend. 

 Acad. Sci. [Paris], 153 {1911), No. 19, pp. 889-891; ahs. in Rev. Sci. [Paris], 

 1,9 (1911), II, No. 21, p. 669).— In a previous article (E. S. R, 23, p. 715) the 

 author showed that the sand particles obtained by ordinary methods of elutria- 

 tion were in many cases covered with a humus clay coating of complex com- 

 position which in strong, compact soils is sufHcieutly large to vitiate the results 

 of analysis. In this article he proposes removing this coating before mechanical 

 analysis by treatment of the fine earth with oxalic acid. 



The complete method of analysis which he proposes consists of the following 

 operations: (1) The determination of lime and the cleaning of the fine 

 earth particles by means of oxalic acid; (2) solution of humus compounds and 

 separation of sand by sedimentation; (3) separation of clay compounds and 

 colloids by centifuging; (4) determination of mineral colloids and humus com- 

 pounds. By this method a complete separation of all the essential con- 

 stituents of soils may be made with great accuracy in a half day. The method 

 also secures the most perfect separation possible of clay, claylike substances, and 

 mineral colloids. 



The soil survey, A. R. Whitson (Rpt. State Conserv. Com. Wis., 1911, pp. 

 51-59). — This article describes briefly the plan and purpose of the soil survey 

 work recently provided for by the Wisconsin legislature and which is to be 

 carried on in cooperation with the Bureau of Soils of this Department. Atten- 

 tion is called particularly to the value of such surveys as indicating the supply 

 of plant food, extent of erosion, possibilities in the development of marsh lands, 

 and the maintenance and increase of soil fertility. 



Collecting' and testing soil samples, C. G. Hopkins and J. H. Pettit {Illi- 

 nois 8ta. Circ. 150, pp. .'t). — Brief, plain directions are given in this circular 

 for taking samples of soil and making simple tests for acidity and carbonates. 



Descriptions of soil types established and changes in classification since 

 the publication of Bulletin 78 {U. 8. Dept. Agr., Bur. Soils [PuJ).], 1911, Nov. 



