64 Journal of Agricultural Research voi. xv, no. 2 



pended in a water bath to such depth that the level of water in the 

 bath was somewhat higher than that of the acid in the flasks. The water 

 was at boiling temperature (about 99° C.) when the flasks were intro- 

 duced, and was so maintained during the solution process. The water 

 level in the bath was maintained by frequent, small additions of water, 

 and the flasks given a rotary shaking each hour. The bumping of the 

 bath insured, however, a constant agitation of the soil patricles in the 

 acid solvent. The maximum difference between duplicates observed 

 when this solution method was followed was equivalent to no more than 

 3 per cent of the potash dissolved. 



a 10 determinations. " Duplicate determinations. 



6 16 determinations. <* 6 determinations. 



The water-bath treatment gave in each case about one-third more 

 potash than was obtained by heating in the steam cups. Because the 

 prescribed conditions were more certainly maintained by use of the water 

 bath, and also because the results thus obtained are the less variable, 

 these results are accepted as the better representing the method. 



POTASH soluble; in warm n/5 hydrochloric acid 



For this determination loo gm. of the fine soil was used in its natural 

 condition of subdivision, with i ,000 cc. of NI5 hydrochloric acid. The 

 dissolving flasks were maintained at a temperature of 40° C. in an electric 

 oven for five hours, and were well shaken at hourly intervals during that 

 period. The solutions were then promptly separated from the undis- 

 solved soil by filtration. A 500-cc. aUquot of the filtrate was evaporated 

 down for analysis. The details of analysis of the solutions were as pre- 

 viously described for the solutions otherwise obtained. 



There were eight determinations for each plot, with results as follows. 



Percentage of 



potrish (K2O). 



Plot I, untreated o. 0143 ±0. 00017 



Plot 4, dressed with potash 0301 ± . 00019 



POTASH SOLUBLE IN DISTILLED WATER 



Determinations were attempted by three different methods of solu- 

 tion, with different ratios of soil to solvent, all at moderate teiiiperatures, 

 of the potash that could be dissolved by distilled water from the respec- 

 tive fine soils in their natural state of subdivision. 



