Sacramento daily record-union., 1882-05-06
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which were formed under the action OF
intense heat, when subjected to the acton
of water readily take up some water OF
hydration. This fact admits of our saying
that the chemical effect Of water on the
transformation of rocks and minerals Is
undoubtedly quite great. Water owes
most OF its efficiency, however, TO It's col
vent power, it being able to dissolve dis-
ntegrate and gradually decompose many
mineral substances. For instance, minerals
like spatite containing soluble cniorides
and other soluble salts give them up TO
the action of pure water. The solvent
effects of water depends Of course upon the
amount of surface exposed; therefore
finely divided and ground up mineral mat
ter is more perceptibly acted upon by
water than il it were in masses. Ii feld-
spar or common glass be ground up to
fine powder and treated with pure water,
blue reactions will be got with red htmus
paper, which prove conclusively that some
of the alkalis have been dissolved out OF
them by the water. The solvent power
OF water is greatly increased by the pres
ence Of carbonic acij. As We have already
seen, this acid is almost invariably found
in considerable quantities in water. This
carbonated water very readily dissolves
many substances which are totally inso-
luble in pure water. Limestone and mag
nestle readily dissolve in it. 1t is the
solution of carbonate of lime which I'M
parts the hardness" to most waters OF
limestone regions. "Chalybeate" waters
are those holding in solution the carbonate
of iron. Silicates are much more readily
deconposed by carbonate than by pure
water.
CARBoNATED WATER
Having such solvent power, it is easily
understood why the water Of soda and
other mineral springs containing much car.
bonic acid are so largely impregnated with
mineral matter. Ordinary river and rain
waters contain very small amount of car
bonic acid and have 3 correspondingly
small solvent power. Analyses made OF
rain water have given from to so parts OF
carbonic acid in 10000 parts of water.
We see, therefore, that the amount of
carbonic acid present in rain waters Is very
variable. River and spring waters contain
more carbonic acid, but much OF 1t Is In
combination with bases, as carbonates and
bicarbonates of the bases, and hence can
have no decided effect on the solvent power
of the water. For all the absolute amount
of carbonic acid is so small, yet, being
spread over a large surface, the aggregate
result of its action becomes in time very
considerable. Next to carbonic acid oyy-
gen probably does more toward the disin.
tegration of rock and mineral than any
other of the atmospheric ingredients. We
have several times spoken of its intense
oxidizing power, or its great affinity for
other bodies. 1t is this same active tend
ency to unite with most other bodies which
imparts to it its usefulness in soil forma-
ton. The low oxides, and the sulphides
of many of the metals, are oxidized to
higher oxides and sulphates which are
more or less needed by plants. Wherever
there is an exposed point of oxidizable
matter there oxygen does its work. The
constant oxidization on the surface of min
erals and rock helps greatly ia their decom-
position. Although unable to treat it at
any length here, oxygen plays very i'm
portant part in the transformation of all
kinds Of matter, both organic and inor-
ganic.
THE GRADUAL EXPOSURE TO THE ELE-
hENTs
Also tends largely to the grinding off and
breaking up of rocks and minerals. By
the term weatheriug we mean the exposure
to the joint influence of water, csrbonic
acid, oxygen and other atmospheric ingre-
dients. The disintegrating and chemical
decomposition under such circumstances
are very considerable, and more so upon
some mineral matter than others, but, ow-
ing to the comparatively limited space at
our command, it would be impolitic to
speak further of this to the exclusion of
more important ones. The last agent in
the manufacture of soil from the recently
cooled down crust of the earth is vegeta-
ton, for the gradual incorporation of
vegetable and other organic matters with
the partly formed soil must have had no
uncomfortable influence on its final con-
struction. 1t probably took centuries of
exposure to the action of the other agents of
disintegration and decomposition before
there was soil enough to support even lieh-
ems, moss, and other of the lowest species
of plants. These plants can't however
thrive on what seems to be bare rock, and
they may be found adhering to the sides of
masses of granite, and even quartz. From
the little nutriment needed by them, they
are we'll calculated to initiate the future
plant kingdom by sacrificing their own in
dividuality and structure for the enrich.
ment and formation Of soil. The decay
and decomposition of successive generations
of vegetable mater gives rise to the humus
of the soil. 1t is brown or black mold
that accumulates on the surface of the soil,
and is composed OF
DECAYING ORGANIC MATTER.
Common leaf mold, peat and swamp
muck are only different notifications of
humus. Peat is formed by the deposition
of successive layers of vegetable matter
under water, and hence out of contact with
the air. L. is almost invariably found in
marshy places and in swamps. Under such
conditions of formation tine decomposition
is not 50 complete as when the matter is
freely exposed to the air. In other words
the matter has not been so completely OK
idiZsd. This fact is taken advantage OF in
some OF the older countries, where the dried
peat is used for fuel, it being surely good
substitute for none. Humus aids in the
dlsintegration effect and formation of soil,
mechanically, by its decay, and chemically,
in the generation of organic acids, ammonia
salts and nitrates, which all have q very
decided solvent effect on mineral matter.
The chemical nature of humus and its rela-
tion to .productiveness will be spoken of in
its proper place. Even living plants d.
rectly contribute to the soil formation.
They shade the soil and keen IL in A more
or less moist condition and we have seen
that carbonic acid is exhaled in consider.
able quantities from living plants. Organic
acids are formed within the plant structure,
and some of which escaping, are free to acs
on the soil and its ingredients.
WHEN undertaking long journey, we
advise you to take along q good supply OF
st. Jacobs Oh in case of an attack of acute
rheumatism or other painful ailments. In
this connection the st. Louis Post Dispatch
relates the following Under the title of ''Old
Proh abilities one nj tho rnoat r1aefnI and