130 
the Clicmical Properties of ISoils. 
It will be noticed tliat the proportions of ammonia wliich are 
absorbed hy the five different soils from a solution of sal- 
ammoniac, containing 79"80 grains of this salt in an imperial 
gallon, vary considerably. 
In the case of the sandy soil very little ammonia indeed was 
absorbed. This is rather singular, since the .same sandy soil 
absorbed a good deal of ammonia on being brought into contact 
with a dilute solution of free ammonia. 
We thus see that a soil may absorb free ammonia in consider- 
able quantities, and yet not have the power of separating and 
fixing ammonia from an ammoniacal salt, such as sal-ammoniac. 
Seventh Series. — Absorption of Ammonia from a Solution 
OF Sulphate of Ammonia. 
A solution of sulphate of ammonia was prepared, containing 
77'70 grains of sulphate of ammonia per imperial gallon, or 20'1G 
grains of ammonia. 1000 grains of liquid therefore contained 
"288 grains of ammonia. The same soil was used in this as in 
the preceding Series of Experiments. In each case 3500 grains 
of soil were shaken up in a well-stoppered bottle with 14,000 
grains of the solution of the above strength. In these experi- 
ments .- Ammonia. 
Grains. 
No. 1. 1000 grains of soil absorbed .. .. "608 
No. 2. .. .. -040 
No. 3. ,, ,, .. .. -576 
No. 4. ,, .. .. -256 
No. 5. - ,, ,, .... -448 
Here again the sandy soil absorbed but very little ammonia. 
There seems thus to be something or other wanting in this 
soil which prevents it from exercising a decomposing influence 
upon ammoniacal salts similar to that manifested by the four 
other soils. I am informed that farmyard manure, guano, and 
other fertilizers of recognized value, produce little effect upon the 
crops growing on this sterile sandy soil. 
Eighth Series. — Retention of Ammonia from a Solution 
OF Sulphate of Ammonia. 
In the Fifth Series of experiments I have shown that a soil 
which absorbed a certain quantity of free ammonia from a 
tolerably strong solution with which it was brought into contact, 
again yielded small quantities of ammonia to repeated washings 
of distilled water. 
It appeared to me desirable to ascertain whether similar 
results would be obtained on washing a soil which had absorbed 
a certain quantity of ammonia from a solution of sulphate of 
ammonia. 
