Sentinel of the valley. [volume] (Woodstock, Va) 1841-1848, 1848-04-06
A G RICUL TU II AL.
AGRICULTURAL SCIENCE.

+,
consist of one and the same material,
viz, granite. !, is Of The oldest or
primary formation; it IS also one Of the
hardest an.. most durable rocks; We, {.
very great portion of all soils have been
derived from The 'li>in'egra,ion Of gran
tie. Rocks, originally Of many tons
weight, have been reduced ia pebbles
pebbles to sand -sand 10 impalpa.
/ HE powder.
Granite is composed Of three mine
rails. VIZ. quartz, trlSpnr. and mica. -
Quartz is the very hard Ainty par, of
granite, it liz often found alone and
pure, AMI is frequently called rock
crystal, white fin: rock, &c. 1t is,
however. Of different colors-w white,
rose, and smoky. In its rlymical
qualities it is considered Of an acid ma
ture. II compoSes much the larger
portion Of most soils, and is lound
nearly pure in the form Of beautiful
white sand upon the shore of seas,
lakes, and many ponds. In agriculu-
raj CHEMISTRY, i, is termed slick, or
silica.
! Slick quartz enters into the com
position OF all plants; were i, not for
this mineral substance, to give strength
or stamina to trees and upright plants,
they would, if they could grow without
It,, al! be trailing plants, unable to rear
themselves from the ground, and have
as little substance in them, as the pola-
to plant has, that vegetables and grows
in the darkened cellar. The ashes Of
land plants yield slick in large quanii-
ty. and it is evidently essential TO the
growth Of plants, as ii forms the sktle-
ton for the sap-vcsseI>, and it also forms
the entire skin (gIaze) Of the corn
stalk, the stems of grapes, the straw Of
wheat and other grains, and on some
of the ra'ans and bamboos, there is
such hard coating as to emf: sparks
when struck by flint, ..
{ Slick is not iuSibIe alone in the hot.
test fire, nor soluble in pure water, and
but slightly soluble in strong acids;
but if mixed in certain proportions with
potash or soda, and subj 'cted to a
strong heat, ii readily melts and forms
the wrll-known substance; glass. If
mixed in the proportion Of one part ST.
lex and two parts potash, it can he
easily melted, and forms soluble
glass, that is, it can readily be dissolv-
ed in boiling water ike sugar or sal;
in this way slick is ar'iGcially rendered
soluble.
Nature, also, has way Of her own,
in dissolving the "while flint rock" SO
as 10 prepare it to De taken up by the
roots o. plants, for the purpose Of form
ing the skeleton, for the support Of the
sap-vessels, and for making the glaze
upon the straw Of wheat, &c.. which is
effected by the laws of Capitalization,
and in point Of fact is perfect coating
Of glass; the object of this coating is 10
project the plant against the attacks of
insects, and to give strength TO the
stem.
1t has been observed, glass is only a
composition Of slick or sand and soda
or potash, fused in the hot fire of a
glass mandatory. That, coating the
stems Of grain, grass, &C., is produced
in lhe soil, simply by chymical union
of silica and potash or soda. The pot
ash and soda are derived from feIspar.
Felspar is one Of the constituents of
granite. 1t is not 50 hard, although il
very much resembles quarz, but it DIFF
fers widely from it in its chymical quail
tiles, being a compound Of slick, alum
ina (ciay) and potash; there is from
twelve to fifteen per cent. of potash in
frlspar, that is, chymis1, by Analysing
100 lbs. offelspar, can obtain 10 or Is
pounds of potash, OF soda, as some
kinds yield potash, others soda. The
potash Of commerce is derived from
wood ashes-soda from the ashes of
sea-plants; potash and grease make
soft soap-soda and grease hard soap;
they have many qualities in common;
both will unite with oils or fat-both
will neutralize acids--both will dis
solve siex- both are alkales.-
Mica, the other constituent Of granite,
contains six or seven per cent. of pot
ash. These three minerals, as mixed
up in our granite rocks, yield about
seven per cent. of potash when ana
/ lyzed.
! Acids and alkalies react upon each
4 other; the decomposition or rotting Of
vegetable matters always produces
calbonic and vegetable acids; IN oar
forests this process is always going on
/ from the rotting of the fallen leaves,
twiggs, branches. and trunks Of trees.
The water Of the soil holding these
acids in solution, they act upon and