ABSORPTION <>! SALTS BY SO U.S. 123 



In the next four 1 trials the third solution was used and the 

 ;in miii its of potash absorbed were: 



Exp. 83 Potash absorbed = 10500 parts per million of clay. 

 Exp. 84 Potash absorbed = 11716 parts per million of clav. 

 Exp. 8T> Potash absorbed 121.">4 parts per million of clay. 

 Exp. 86 Potash absorbed = 20870 parts per million of clay. 



In experiment 83 the digestion covered 12 hours with the 

 solution cold, in the ratio of 2000 of soil to 4000 of solution. 



In experiment 84 the mixture was boiled one-half hour. 



In experiment 85 the clay was first treated with hot hydro- 

 chloric acid and afterwards as in experiment 84. 



In experiment 86 a yellow clay from Cromwell was used, 

 first treated with hydrochloric acid, boiling one hour, and sub- 

 sequently digested, at high temperature, 24 hours ; then washed 

 with distilled water and dried before using. The ratio of clay 

 to solution was 500 to 2000 in this case. 



To obtain the results here cited Dr. Peters prepared a quanr 

 tity of a rather clayey soil derived from the disintegration of a 

 claystone porphyry, the analysis of w T hich is given in Bulletin 

 "B,"p. 7. Solutions containing different potash salts in different 

 amounts were prepared and 100 grams of the air-dry soil were 

 digested in 250 c. c. of these solutions during 24 hours; the soils 

 being introduced into a stoppered flask and the mixtures, at 

 first, subjected to vigorous shaking. Portions of the liquid 

 above the soil were drawn off with a pipette for analysis. 



There is given in the next table two sets of absorption re- 

 sults, one with the solution cold and in contact with the soil 

 24 hours, the other, where the soil was boiled in the solution 

 one-fourth hour and then allowed to stand 24 hours. 



*Die landwirthschaftlichen Versuchs-stationen, Volume 2, p. 113. 



