AGRICULTURAL PROGRESS AND EXPERIMENTS, 571 
from the commercial centres on the coast, the high freight- 
charges of the railways, the dryness of the soil, and the 
uncertainty whether there will be moisture enough to make 
chemical manures available for the crops they are applied 
to, make artificial fertilizers to be used at too great a dis- 
advantage. But it is of almost, if not quite equal, impor- 
tance, that the improvement of agriculture in the direction 
I am indicating should be taken in hand in the same manner 
the world over. 
The soil, I need scarcely remind you, “is by no means the 
inert thing it appears to be. It is not a passive jumble of 
rock-dust, out of which air and water extract the food of 
vegetation. It is not simply a stage on which the plant 
performs the drama of growth. It is, on the contrary, in 
itself the theatre of ceaseless activities—the seat of per- 
_petual and complicated changes.’”* The soil, as regards its 
components, is of most varied and complicated constitution. 
Not only does it contain a large number of chemical 
elements, but these elements occur in it in widely differing 
proportions and in many different combinations. The soil 
is of most complex constitution, and there is scarcely a single 
soil in regard to which we are not still, to a very large extent, 
ignorant of the manner in which the elements of which it is 
made up are associated and combined; while the intro- 
duction into it of a fresh substance, or an increase or 
diminution of the quantity of a substance which is already 
in it, or the action of a fresh force, or an increase or 
diminution of any of the forces which are already acting 
on it, may be the cause of wide-reaching changes in it. Any 
of these, because of the apparently simple chemical changes 
they produce directly, may be the cause of a whole cycle of 
fresh changes. The causes of disturbance are so manifold, 
that it is doubtful if anything approaching a state of 
chemical equilibrium is ever reached in a soil—in a fertile 
soil, at any rate. The temperature of the soil, like that of 
the atmosphere, is constantly changing; and a rise during 
the day may lead to certain chemical actions, and a fall at 
night to counter-actions. A shower of rain, or the acid 
juices of plants growing in it, may dissolve out certain sub- 
stances from a mineral ingredient of the soil, and this may 
lead to a long series of changes in its other constituents. 
The decay of organic substances may set free acids or gases, 
or lead to the formation of fresh substances, which cause 
disturbances of chemical relations. These incessant changes 
and their complexity make it to be that we are to a very 
* From Johnson’ s “ How Crops Feed.’ 
