ABSORPTIVE POWER OF THE SOIL 339 
We observe that potash was absorbed in this case in 
largest proportion from the phosphate, and in least from 
the chloride. Henneberg 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 eee 
“sulphate, 12 ee 
“ hydrate and chloride,* 11'|,  “ 
“ chloride, iL eS 
“nitrate, sal * 
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 fact, 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 water 
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 
solution was removed, and its place was supplicd with 
pure water. After two days more, one-half of the liquid 
was again removed, and an equal volume of water added ; 
* Chloride of Ammonium, NH,Cl. 
