Liquid Manure, 
147 
Noticing the chief points of interest that attach to these 
results, I would direct attention to the following particulars : — 
1. It will be seen that this sandy soil possessed in a very weak 
degree the power of absorbing ammonia from liquids. Thus, 
1 gallon of liquid, after having remained in contact with soil for 
24 hours, only contained 2 43 grains less ; or, in round numbers 
2^ grains less of ammonia. This small quantity, it will be 
remembered, is removed by 20,000 grains of soil ; 1000 grains 
consequently absorbed only 121 of a grain of ammonia. In this 
particular this soil offers a striking contrast to the soils used in 
the preceding experiments, which absorbed about 6 times as much 
ammonia. 
2. The proportion of Organic matter in the filtered liquid is a 
little larger than in the original liquid ; but no appreciable differ- 
ence exists in the amount of nitrogen in the organic matter before 
and after filtration through the soil. 
3. In passing through the red-coloured sandy soil, the liquid 
manure took up an appreciable quantity of oxide of iron. In all 
probability the oxide of iron was united with an organic acid, or 
with organic matters similar in character to the organic matters 
found in bog-iron ore. 
4. The soil used in this experiment, it will be remembered, 
contains a good deal of soluble silica. Liquid manure in con- 
tact with it appears to dissolve an appreciable quantity of soluble 
silica. 
5. In the two preceding experiments we have seen that liquid 
manure kept in contact with soil becomes much richer in lime. 
But in the case of the sandy soils, instead of lime being taken up 
by the liquid manure, a considerable quantity of the carbonate of 
lime contained in the liquid used in the experiment was actually 
removed by the soil. The amount of lime in this soil is evidently 
insufficient to supply the wants of the crops we cultivate on the 
farm ; it is therefore fortunate that a soil thus constituted pos- 
sesses the power of depriving manuring mixtures of those con- 
stituents which are required in considerable quantities for sustain- 
ing a healthy growth of plants. This property of soils to store 
up food for plants is not confined to one particular kind of 
fertilizing matter, but it applies to them all, and manifests itself in 
different ways. In most cases special power exists in soils to 
remove ammonia, potash, and phosphoric acid from liquid fer- 
tilizers brought in contact with them ; and less important and 
more abundant materials pass into the liquid that drains from 
soils. But this order is reversed if liquid fertilizers act upon such 
soils as the one used in the experiment before us. Here lime, 
a cheap and usually abundant ingredient of soils, is actually 
L 2 
