Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1882-03-11
AGRICULTURAL PAPERS.
A sERIEs PREPARED ESPECIALLY FOR
TIE "RECoRD-UEIoN."
Presenting instruction Contained in Lect-
ures from The Chair of Agricult-
ure, State University.
NINTH PAPER !

NINTH PAPER
Aluminium is rare and not well known !
mineral. It's oxide (alumina), however,
constitutes a large portion of the earth
crust. The pure alumina is found only in
some Of the rare mineral gems-corundum,
sapphire and ruby. 1t is a constituent in
large quantities Of slaty rocks and of clays,
some of which are almost pure alumina
These cIays Increase in tenacity as the pro.
portion II aumina in them increases. The
pure aIr1ujna is an earthly substance, is
white, tsstgle-s and odorless, and adheres
with more or less tenacity to the tongue
This Is OWING to the avidity with which 1t
absorbs wasar. It is not soluble in water,
but readily lssolves in the caustic alkalies,
and in most acids. II alumina be heated
TO 2 red hsss liz becomes hard and dense,
and almost in=olGble, even in the strongest
acids. Altsousl Of such general occur
renee il ths soil. aiunina contributes but
little to The E9urishmen5 of plants but a
very small Der cent Is found ID the ash of
plants, and i, if anything more than me-
chanical sgen., seems only to take an in
direct part IL plant growth. The sulphate
of alul,niam Exists naturally in some
soils, more especially in the vet. marshy
ones. J. IS very soluble In water, and has
a well-dshned and peculiar sweetish,
astringent taste. Phosphate of aluminium,
when con pared with the other phos phates,
seems to be o substance of secondary or of
.l,,, akoI
Owing 70 tho great difficulty Of making
perfect separation OF slumina from phos-
phoric acid IN analytical analysis, the re-
suits obtained f0r the presence OF phosphate
of aluminium have heretofore been TO some
extent only approximations, and for that
reason no direct and accurate proofs exist
as to ths eXse5 amount of this substance in
soils. TIE common alum of commerce is i
doutle snlPhate of potassium and alumni
Jun, with Ja anty tour parts of water. It
is of natural occurrence in many parts of
the world, and in some places forms an
encrust&tioG on tie surface of the ground.
SILICA.
Silica aad It's compounds are the chief
ingredients OF sand, sandstone, and many
sandy soils, Of flint, quartz rock and rock
crystals. IL Is common ingredient, to
certain extent, of all soils, OF the ash of
all plants, and constitutes very consider.
able par5 Of the ash of many of the plants,
especially the cereals and the grasses The
purer forms of silica, quartz, flint, etc,
are absolutely insoluble in water, quite
insolub.e in acids, and are acted upon but
slowly By the alk2lis. When heated to a
high Temperature with potassium or
sodium, sIJcz combines or fGse5 with them
TO form a glass. The glasses are, as gen.
aerRl thing either the sIlicate of one of the
alkali bases or a mixture Of several OF the
alkah sil.cates. Although silica and its
compounds are among the most stable
substances known, yet 1t may be pre-
pared chemically, and exists naturally
in form which Is soluble even in water.
Silica is one of the most abundant sub
stances in nature. It exists in combination
with potassium, sodium, calcium, magne-
sium and aluminium, forming many of the
crystalline rocks. By the processes of
nature these silicates undergo a gradual
decomposition, and are conveyed by the
waters of she rivers ON to the valleys In
She form of soluble silicates, which go to
make up the "siliceous portion Of all
sols. In the living plant silica exists to
Il large extent in combination, and disposed
.am0rg the cells and coats of the plant as
a delicate tissue. In numerous cases it is
4 deposited on the outside OF the plant, as
almost pure silica, and can be separated
iy mechanical means in the form OF scales.
: is this substance which Imparts the
s. las TO the exterior surface of many
plants, for infrance, the bamboo, corn
stalls, reeds, etc, the stalks of which
contain large percentage of the insoluble
aiEclrcs OF potassium and sodium.
u -tcre these insoluble silicates, which
exist - a large extent in the mineral king
dom. ara gradually acted upon by the car
bozic sciG OF the air, which unites with the
5ase & the siiicates of potassium or sodium
&a 81 n carbonates of the bases, and these
ar soluble in and washed away by the rain
~ ,, and are by it carried on to the land
aej8w. The silica itself is left in a form
which IS quite soluble in carbonic acid, and
TO a certain extent In water. Hence we
see that by the action of natural agents
both the bases and the acid eff silicates are
80 large extent rendered available to the
plant world In the manure heaps of the
farm-yard, where vegetable matter is I'M
dergoing decomposition, the silicates which
they contain, sometimes Is very considera-
BILE quantities, undergo the same process of
Transformation, by which means the silica
is rendered soluble and again made avail
able for plant growth.
THESE sILIcATEs
Not only exist naturally in the soils, but
are under certain conditions formed in the
soils from constituents inherent in it. By
the addition of potassium or sodium the
production Of the soluble silicates might
probably take place to some extent. If
the soil be sandy it is more than probable
that the insolubie silicates OF there basis
will be formed, and the beneficial effects of
the application OF potash and soda fertil-
izers to such soils will be quite noticeably
less than on other soils, for the simple
reason that a large per cent. of the alksli
bases added have been locked up in the
form of insoluble silicates. These silicates,
though iusoluble In water and thus not
directly available to plants, are yet soluble
20 a greater or less extent by the acids,
principally organic, OF the soil which are
In most cases products of decayipg vege-
table matter. The fact that the silicates
insoluble in water are thus acted upon by
the organic acids which are generated by
decomposing vegetable matter, suggests to
the practical farmer, who has failed to per-
ceive sny direct returns from the addition
of mineral fertilizers, the fact that by the
addition OF vegetable manures these organic
acids viii be generated, which will in turn
act as solvents on the silicates, thus max
ing available both Of their ingredients, the
base and silica This fact accounts fer the
very marked results which are sometimes
obtained by applying vegetable manures to
soils w6ich have for some time been man.
ured only by mineral fertilizers.
IRON.
Iron forms with oxygen two compounds,
known as the protoxide and the per or
sesquioxide of iron. The first consists of
sne atom of iron and one Of oxygen, while
fha second contains two atoms of iron and