340 HOW CROPS FEED. 
and this process was repeated ten times. The soil lost 
thus in the several washings as follows: 
In 2d, 3d, 4th, 5th, 6th, wth extract. 
0.0075 0.0096 0.0082 0.0069 0.0075 0.0082 grams. 
In 8th, 9th, 10th extract. 
0.0112 0.0201 0.083 grams. 
Removed in all, 0.0875 gram of potash. 
Remained in soil, 0.1239 gram. 
In these experiments one part of absorbed potash re- 
quired 28,100 parts of water for solution. = 
Similar results were obtained by Henneberg and Stoh- 
mann with a soil which had absorbed ammonia; one part 
of this base required 10,000 parts of water for re-solution. 
It has been already stated, that the absorption of one 
base is accompanied by the liberation of a corresponding 
quantity of other bases, while the acid element, if it be 
sulphuric or nitric acid, or chlorine, is found in its 
original quantity in the solution. As an illustration of 
this rule, the following data obtained by Weinhold in the 
treatment of a soil with sulphate of ammonia are ad- 
duced. The quantities are expressed in grams, except 
where otherwise stated. 
Content of Solutzon a 
— eS a 
before after 
contact with the soil. contact with the soil. 
TAS i Ge 3 | “Asneds 
os J s 3 S$ 4 s ; 
Ss Ss s S ‘ - 
<=] 8° >= = | Ss Ses Ss 3 
Nsiss8/]o8 | 3S || 28 | 38 q B N = 
1 300 0.303 0.129 || 0.329 | 0.056 0.012 0.121 | 0.110 0.049 
1%| 200! 0.455 | 0.193 0.488 | 0.120 | 0.011 0.034 | 0.105 | 0.030 - 
We observe that the soil not only retained no sulphuric 
acid, but gave up a small quantity to the solution. Of 
the ammonia a little more than one-half in one case, and 
three-eighths in the other, was absorbed, and in the solu- 
tion its place was supplied chiefly by lime, but to some 
extent also by potash, soda, and magnesia, which were 
dissolved from the soil. It is also to be noticed that in - 
the two cases—unlike quantities of the same soil and 
