IF. A. Drusliel— Cobalti-Nitrite Method. 



331 





Character 



Soil taken 





K 2 



found 



No. 



of soil 



grm. 



Method 



grm. 



per cent. 



I 



Clay 



(i) 



2*5 



vol. 



0-0028 



o-ii 







(2) 



t< 



l< 



0-0035 



0-14 







(3) 



a 



grav. 



0-0035 



0-14 



II 



Clay 



(1) 



it 



v. 



o-oioo 



0-39 







(2) 



a 



(C 



00092 



0-37 







(3) 



a 



g- 



0-0093 



0-37 



III 



Loam 



(!) 



a 



V. 



0-0074 



0-30 







(2) 



a 



it 



0-0068 



0-27 







(3) 



a 



g- 



0-0075 



0-30 



IV 



Loam 



(1) 



u 



V. 



0-0060 



0'24 







(2) 



a 



a 



0-0058 



0-23 







(3) 



a 



g- 



0-0058 



0-23 



V 



Gravel 



(1) 



it 



V. 



0-0042 



0-17 







(2) 



a 



g- 



0-0045 



0*18 



VI 



Gravel 



(1) 



a 



V. 



0-0047 



0-19 







(2) 



a 



u 



0-0044 



0-18 







(3) 



a 



g- 



0-0050 



0-20 





Clay 



(1) 



it 



V. 



0-0048 



0*19 



711 



Gravel 



(2) 



a 



g- 



0-0046 



0-18 







(3) 



a 



V. 



0-0045 



0-18 







(4) 



a 



a 



0-0040 



0-16 







(5) 



a 



a 



0-0044 



0-18 



The following exceptions are to be noted to the general 

 method previously outlined for the preparation of the sample. 

 In I the excess of hydrochloric acid, the iron, aluminum and 

 calcium were removed from the separate portions after aliquot- 

 iug, and in (1) and (2) sodium carbonate was used instead of 

 ammonium hydroxide and ammonium oxalate for the removal 

 of the iron, aluminum and calcium. In Y (1) and (2) bases 

 other than the alkalis were removed in the separate aliquots 

 by ammonium hydroxide and ammonium oxalate. In YII 

 the aliquots were made directly from the hydrochloric acid 

 extract. That of YII (2) was treated in the usual manner 

 for the gravimetric estimation of potassium. The other 

 aliquots of YII were evaporated to dryness and gently ignited 

 to remove any ammonium chloride present and to char the 

 organic matter. The residues were extracted with hot water 

 and a little acetic acid, filtered and evaporated with sodium 

 cobalti-ni trite in the usual manner. 



In this work the results are based on a small amount of soil 

 (2*5 grm.) in each case because but a limited amount of each 

 sample was available. A higher degree of accuracy may be 

 secured by using 10 grm. of soil for each estimation instead of 

 2*5 grm. 



