24

frozen than when in the liquid state, is one of the chief mechani-
cal causes in destroying the cohesion of rocks and stones. It is a
well known fact that this increase of the bulk of water, when fro-
zen, is able to overcome any resistance, however great, which may
oppose it. Compared to it, gunpowder and steam sink into insig-
nificance. In autumn, during rains, we find mountainous countries
very moist; caverns and fissures, which exist in rocks are then
filled with water, which gradually leaks through the smaller clefts,
percolates through the pores, until finally, it pervades every part of
the rock. With the first freeze the inclosed water is converted
into ice, expands and bursts the rocks which oppose the expansion,
which thus become converted into small fragments. In spring,
when a thaw takes place, the rivers and streams which flow from
the mountains are filled with water holding earthy particles in sus-
pension, (the fragments of rocks broken by previous frosts,) which
are borne down by the rivers to the various districts watered by
them.

The mountain rivulets, nearly dried up in summer, become
strong, and by their fall, rapid torrents in winter; forming thus a
brisk and rapid communication between mountains and valleys.
In a level country, rivers find a comparatively spacious bed; and
when over-flowing their banks, deposit the material which they
hold in suspension,—thus forming, according to the nature of
the rocks through which their branches flow, a more or less rich
soil.

The soil, the present subject of our consideration, is to be ex-
amined in a manner which, of course, must differ from the methods
commonly applied to minerals, &c., as well in regard to a sepa-
ration of the substantial from the unsubstantial, by which, most
especially, time will be saved, as it must at the same time include
an investigation into the nature of its composition in general and
of the components in particular. On the condition and form in
which those substances exist in the soil, depends entirely the mode
of their participation in the development of plants, whether they
partake directly or indirectly, as active, as reserved, or as passive
components. An analysis which does not offer a full sight, into
all these conditions, is nothing but a worthless work, from which
neither practical nor theoretical conclusions can be drawn; and it
is certainly not too much said when I pronounce the existence of
the many analyses of soils, which are distributed through books or
daily manufactured by Chemists, and which show every thing but
that which is essential for the farmer to know, to be the reason of
the discredit into which chemical agriculture is sunk in the minds
of so many rational husbandmen. For it is important, besides
the performance of a chemical analysis of soil, to take notice of its
locality, physical properties, former improvements, and the condi-
tion in which the soil-constituents exist in it. It may be said that