RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY. 



On uniformity in soil analyses, A. I). Halt. (Ant/h/ftf, 26 (1900)^ 

 Wo. 296, pp. 281-291). — This article o-ives the recoiiiinendations of a 

 committee of the Agricultural Educational Association, consisting of 

 T. S. Dymond, M. J. R. Dunstan, C. M. Luxmoore, T. B. Wood, and 

 A. D. Hall, as well as some of the results obtained b}' members of the 

 committee in testing the methods proposed and a discussion of them 

 by B. Dyer and others. The recommendations are as follows: 



I "(1) Taking sample — Under ordinary conditions the sami^le shall be taken to a 

 depth of 9 in., Ijut in case of shallow soiLs to such lesser depth as marks a natural line 

 of demarcation. The committee approves of the use of the auger as one method that 

 may be adopted f(jr taking samples. Several cores should 1)0 taken and mixed for 

 analysis. 



"(2) Drying. — The sample shall l»e air-dried for analysis. The drying may be 

 accelerated by heating to a temperature not exceeding 40° C, but in all cases the 

 soil should be finally left for a day or two, spread in a thin layer, and exposed to the 

 air at the ordinary temperature of the room. 



"(3) Sifting. — A sieve with round holes, .3 mm. in diameter, shall l^e used to sepa- 

 rate the fine eartii for analysis from the stones and gravel. Gentle pressure with a 

 wooden or caoutchouc pestle or other means may be adopted to ))reak up aggregates 

 of clay and silt, but care should ))e taken not to crush any of the stones or lumps of 

 chalk.' 



" For determination of the 'available constituents' tiie 'fine earth' is used without 

 grinding. For the other determinations 100 gm. or more of 'fine earth' is sifted 

 through a woven sieve of 40 meshes to the inch, or a sieve with round holes of 

 1 mm. in diameter. What is retained by the sieve is ground till it will pass through, 

 and the whole mixed. Perforated zinc, with holes I in. and 2^- in. diameter, is com- 

 mercially obtainable, and forms a convenient material for the construction of the 

 tAvo sieves. . . . 



"(4) Determination, of moisture. — The sample is <lrie(l in the steam oven to constant 

 weight. 



"(5) Determination of lo.sn on ignition. — The result shall be so expressed as not to 

 include the carbon dioxid expelled from the carbonates nor the moisture previously 

 determined. 



"(6) Determinatio)i of nitrogen. — -Unless titherwise specified, the nitrogen shall be 

 determined In' Kjeldahl's method. 



"(7) Detennination of carbonate of lime. — The carbon dioxid evolved on treatment 

 of the fine earth with acid is calculated as carbonate of lime. 



"This is regarded as a convenient measure of the 'available basicity' of the soil, 

 without discriminating between carbonates of lime and magnesia. 



"(8) Detenninatio)!, of ^totaV mineral conatituentn. — The fine earth is boiled with 

 strong hydrochloric acid in an open flask for a short time in order that the acid may 



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