On the Chemical Properties of Soils. 
129 
It is one of the functions of soils to check the accumulation of 
soluble fertilizing matters, and this function it performs in many 
instances by rendering insoluble, or, to speak more correctly, by 
greatly reducing the solubility of those important fertilizing 
matters which would otherwise induce an unhealthy or abnormal 
growth of plants. • Considering the structure of the spongioles of 
the roots of plants we readily comprehend how important it is 
that such matter should be able to find its way into the vegetable 
organism. Whilst thus it is the particular function of the soil 
to present the loss of ammonia from manures, such as guano, 
sulphate of ammonia, &c., which we are in the habit of applying 
to the land, provision is made that the ammonia, when it becomes 
fixed by the soil, should not be rendered so entirely insoluble 
as to be of no direct benefit to plants. 
In short, all soils, clay as well as sand, store up ammonia with 
great eagerness, and part with it reluctantly. 
Sixth Series. — Absorption of Ammonia from a Solution 
CONTAINING CuLORIDE OF AmMONIUM. 
In this series of experiments I endeavoured to ascertain the 
amount of ammonia which soils of known composition absorb 
from a standard solution of sal-ammoniac in water. 
The solution used in the following experiment contained 
79*80 grains of chloride of ammonium in the imperial gallon, 
or 25"20 grains of ammonia ; or 1000 grains of this solution 
contained 1'14 grains of chloride of ammonium, or "36 grains of 
ammonia. 
The soils experimented upon were the same as those used in 
the First Series of Experiments, namely : — 
1. A calcareous clay. 
2. A fertile loam. 
3. Stiff" clay soil. 
4. Sterile sandy soil. 
5. Pasture land. 
In each case 3500 grains of soil were mixed with 14,000 grains- 
of a solution of chloride of ammonium, containing 'SB grains of 
ammonia in 1000 grains of liquid. After standing three days 
the clear liquid was drawn off", and the ammonia contained in it 
obtained by distillation with caustic potash. The operation was 
conducted in each case alike, and the following results were 
obtained : — 
No. 1. 1000 grains of soil absorbed 
No. 4. 
No. 0. 
Ammonia. 
Grains. 
. -68 
. -76 
. -80 
. -16 
. -64 
VOL. XXI. K 
