ABSORPTIVE POWER OF THE SOIL 339 



We observe that potash was absorbed m this case in 

 largest proportion from the phosphate, and in least from 

 the chloride. Ilenneberg and Stohmann, operating on a 

 garden soil, observed a somewhat different deportment of 

 it towards ammonia-salts. 10,000 parts of soil absorbed 

 as follows: — 



From phosphate, 21 parts. 



(( 



hydrate, 13 " 



" sulphate, 12 " 



" hydrateand chloride,* ir I, " 

 « chloride, 11 



" nitrate, U " 



Fixation neither complete nor permanent. — A point 

 of the utmost importance is that none of the bases are 

 ever completely absorbed even from the most dilute solu- 

 tions. Liebig indeed, formerly believed that potash is en- 

 tirely removed from its solutions. We find, in lixct, that 

 when a dilute solution of potash is slowly filtered through 

 a large body of soil, the first portions contain so little of 

 this substance as to give no indication to the usual tests. 

 These portions are similar in composition to drain-waters, 

 and like the latter they contain potash in very minute 

 though appreciable quantity. 



In accordance with the above fact, it is found that icater 

 will dissolve and remove a portion of the potash, etc., 

 which a soil has absorbed. 



Peters placed in 250 c.c. of a solution of chloride of 

 potassium 100 grams of soil, which absorbed 0.2114 gram 

 of potash. At the expiration of two days, one-half of the 

 solittion was removed, and its place was supplied with 

 pure water. After two days more, one-h:ilf of the liquid 

 was again removed, and an equal volume of water added j 



♦ Chloride of Ammonium, NH^Cl, 



