Oct. 14. 1918 Fertilizer Potash Residues in Hagerstown Silty Loam 67 



POTASH SOLUBLE IN CARBONATED WATER 



The quantities of soils used and arrangement of apparatus were sub- 

 stantially the same as those in the percolation with distilled water. 

 The principal modifications consisted in ( i ) the delivery of water charged 

 with carbon dioxid at air pressure and room temperature by means of a 

 continuous current of the gas passed through the water in the Bunsen 

 bottle; and (2) the closing of the top of the percolator tube by means of a 

 one-hole rubber stopper, to prevent loss of the gas from the apparatus 

 at that point. 



The percolations were continued until in each case 500 cc. of percolate 

 had been extracted. The linen filter was washed in both percolation 

 tests with a spray of water to remove any soluble film that might have 

 been deposited by evaporation of the percolate. The washings were 

 added to the latter. 



The usual analytical procedure was followed, with these results, in 

 terms of the air-dry soil: 



While the percolates M^hich passed more slowly through the soil con- 

 tained more potash than those which passed quickl)^ the increase was not 

 proportional to the time of percolation for either soil. 



POTASH SOLUBLE IN AMMONIUM-CHLORID SOLUTION 



One hundred gm. of the air-dry fine soil in its natural state of sub- 

 division were heated with 1,000 cc. of the neutral-salt solution for five 

 hours in an electric oven at 40° C. with hourly shaking. At the end of 

 the heating period the liquors were immediately filtered off from the 

 undissolved soils, and subjected to the analytical procedure previously 

 described. 



To find a satisfactorily active solution concentration of the ammo- 

 nium chlorid without too greatly increasing the amount of this salt that 

 must later be removed in the analytical process, the effects of solutions 

 containing 17.6 and 50 gm., respectively, of the salt in i liter of dis- 

 tilled water (approximately N/j and normal solutions) were compared 



