350 Sort ANALYSIS. 


‘conventions ”’ to be settled by considerations of expediency 
and mutual agreement. But as the results obtained will 
very largely depend upon the conventions adopted, the 
Committee have attempted, after discussion and investiga- 
tion, to so far define a common plan of action as will render 
the results obtained more generally serviceable, without 
hampering the individuality of each worker. The recommen- 
dations are as follow :— 
(1) Zaking Sample.—Under ordinary conditions the sample 
shall be taken to a depth of 9 inches, but in case of shallow 
soils, to such lesser depth as marks a natural line of 
demarcation. The Committee approve of the use of the 
auger as one method that may be adopted for taking samples ; 
several cores should be taken and mixed for analysis. 
(2) Drying.—The sample shall be 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) Szfteng—A sieve with round holes, 3 mm. in diameter 
shall be used to separate the fine earth for analysis from the 
stones and gravel. Gentle pressure with a wooden or 
caoutchouc pestle, or other means, may be adopted to break 
up aggregates of clay and silt, but care should be taken 
not to crush any of the stones or lumps of chalk. For 
determination of the “available constituents,” the “ fine earth” 
should be used without grinding. For the other determina- 
tions, 100 grams or more of “fine earth”’ shall besifted 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 to be ground till it will pass through, and the whole 
mixed. Perforated zinc, with holes one-eighth inch and one 
twenty-fifth inch diameter, is commercially obtainable, and 
forms a convenient material for the construction of the two 
sieves. Considerable diversity of opinion exists concerning: 
the sieve to be used for obtaining “fine earth” for analysis. 
The Rothamsted chemists employ a woven sieve of one-~ 
quarter inch mesh; the 3 mm. round-holed sieve was 
originally suggested by Wolff; the Berlin Ladoratortum fir 
