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1884.J Analyses oj Books. 
to the geological features and general local circumstances of the 
State of Alabama, it may be profitably studied by all interested 
in the future of Agriculture in any part of the world. 
The author has prepared himself for his task by a careful study 
both of the natural phenomena of the district and of all the 
more important works in which agricultural chemistry is ex- 
pounded. He begins with a general discussion of the composi- 
tion, mode of formation, and properties of soils, and of the 
changes produced by cultivation. After treating very fully and 
carefully of the soil in its chemical and geological relations, of 
the conversion of rock into soil, and of the mechanical aCtion of 
water and other denuding agencies in removing the waste pro- 
duced by weathering, he goes on to consider the soil in its rela- 
tions to vegetation. Among the organic agencies concerned in 
the production of soils the aCtion of earth-worms is not forgotten. 
The views of Darwin have, it appears, been confirmed by prac- 
tical men in Alabama, as elsewhere. We are told that “ it has 
not escaped the observation of many farmers in this State that 
when a mass of sand has been washed down over a fertile bottom, 
it will, in a few years, again be covered by a layer of vegetable 
mould which earth-worms have, in the manner indicated, brought 
up from below and spread over it.” 
Passing on to the soil in its relations to animal life, Dr. Smith 
gives emphatic prominence to certain considerations too gene- 
rally negledted. He shows that wherever plants alone are con- 
cerned there is a full restitution of plant-food to the soil. Its 
fertility, indeed, is not merely maintained, but enhanced, “ since 
by the constant aCtion of the weather, aided by the acids, &c., 
produced by the decay of one generation of plants, the inert 
constituents of the soil are gradually turned into an available 
form, and thus placed at the service of another generation.” 
Animals, however, disturb this equilibrium to some extent, and 
by the intervention of man the natural provisions for maintaining 
the fertility of the soil are further compromised. Not merely is 
a portion of vegetable matter removed year by year in the form 
of the crops, but by the destruction of the forests “ the inequali- 
ties of the rainfall are very much exaggerated, heavy rains alter- 
nate with protraCted drought ; the soil, deprived of its protecting 
coat of vegetation, is exposed to all the destructive aCtion of the 
rains, by which it is loosened and in a great measure carried 
away to be deposited again in the valleys ; and the hill-sides, as 
well as the gentle slopes, are disfigured and ofcen rendered unfit 
for cultivation by the cutting of gullies and ravines. With loose, 
loamy soils, such as characterise the greater part of the State of 
Alabama, the destruction of lands from this cause probably far 
exceeds their exhaustion by the improvident systems of culture 
usually followed.” 
We may add that this process of denudation, by which the 
soils are carried away into the valleys, and even into the river- 
