Sacramento daily record-union., 1882-05-06
AGRICULTURAL PAPERS.
a SERIES PREPARED ESPECIALLY FOB
THE "REcoRD-UHIoN."
Presenting instruction Contained in Lect-
ures from the Chair Of Agrtcult-
ure, State University.
IsEvExrKESTH PAPER ]

IsEvENTEESTH PAPER
Geological study seems to indicate that
the entire earth was once in a state OF
fusion, and that the crust was formed by
gradual cooling from the surface inward.
The crust could not have differed greatly
at frat from the solidifed lava of volcanic
regions. and it was undoubtedly incapable
of affording nutrition to plants. Since
coils are made up of fnely-divided par
ticles OF rock, it is evident that the first
step toward the formation OF soil as
medium in which plants should grow, was
the decomposition and pulverzation of this
igneous matter by physical and chemical
forces. The causes which have produced
these results are great, although the re-
salts of their action during one OF our gen.
erations are not so strikingly apparent. II,
however, we take into consideration the
mass Of the earth which has remained un-
influenced by these agents of soil manu-
fseture, their action has been infinitely
small. This insigni6cance can only be
realized by comparing the average depth
of the soil, which may be measured even
in feet, with the diameter Of the earth, SO
that the soil is in reality only thin coat
ing OF dust over the earth's surface. The
formation of soil from rock has been
brought about, 1) by results of changes of
temperature ~ by the action of moving
water and ice; (3) by decomposition in
duced by the chemical action Of air and
water; and I4) by the influence of
ANIMAL AND VEGETABLE EIFE.
1t is well known fact that by heating
we increase the volume of almost every
body, and that by cooling we decrease its
volume. Just so the earth's crust must
have been expanded while in the molten
condition. When it began to cool a
gradual shrinkage took place. One effect
OF this contraction would have been q SUBJ
sidence of portions of the crust and a
wrinkling Of other portions, thus produc-
ing on the one hand sea- basins and valleys,
and on the other mountain ranges. This
would have been followed by cracking or
fissuring in many places of the crust ITSELF
During this contraction and shrinkage, to-
gether with the weight of superintendent
material, immense weight was brought to
bear upon the lower strata of the crust
with the formation OF laminated or slaty
rocks. Thus we see that the first changes
of temperature exerted an immense inhu-
ence in the breaking up and final pulveri-
xation OF the surface of the forming crust,
and in the forming OF many of the different
notifications OF rock. Besides this direct
influence which the change of temperature
has had upon the earth's crust, it has been
the indirect cause of other or beneficial
changes. Ia the rending action OF freezing
water, force is exerted which can hardly
be realized. In the change from the
liquid to the solid form, the volume OF
water increases six to seven per cent. The
water of rains soaks into and fills up the
innumerabie cracks and crevices of rocks
and hillsides, and with the lowering of the
temperature this water freezes, expands,
and tears open and bursts off immense
masses of rock and earth. In cold coun-
tries the effects produced by this ever
acting agency OF freezing water are stu
pendous, while IN more temperate regions
its results, though invariable, are not SO
marked. Tie action of freezing water
separates particles of rock from the COM
mon mass quite as effectually as where the
water can find its way into larger aper-
lures. Masses of granite may be split by
drilling rows Of holes in it, filling them
with water, aud allowing the water to
freeze.
Does more to perceptibly change the ap-
pearance of the earth's surface than any
other cause. Although not familiar from
experience with the glacial action of ice,
L IL r l.
and rock are cemented up in the noun
tains of ice which fill the Arctic regions
and that as the action of the sun and con-
tact with warm currents meet these masses
of ice, they deposit their burdens, which
may have been transported hundreds of
miles. The amount of detritus deposited
by these means is slight compared to the
masses which have been moved by the
glacial action of ice. The seemingly mo-
tionless ice fields-in reality frozen rivers
which are formed far above the line of
perpetual snow, move by slow, inter
mittent motion down toward the "no
frost line," which, once reached, they
proceed to melt away, and disappear in
numerous miniature rivers, which hurry
along in their rush toward the sea. Begin.
ming at the summit of some high noun.
tain, the embryo glacier descends slowly
by its own weight continually meeting in
its course banks of snow and ice which are
impregnated with masses of rock and min
eral matter from the hillsides and cliffs, it
steadily adds to its own bulk till there are
often glaciers of a mile in depth and carry
ing millions of tons of foreign matter to
the regions below. The middle of the
glacier, moving more rapidly than the
sides and bottom, grinds up, by their mu-
tual friction, the rocks and stones i'm
bedded in it. The moving mass of ice
carries everything before it in its slow mo-
tion, until reaching the warm temperature
of the lower slopes, when it melts away
and deposits its mass of mud, gravel and
rock upon
ITS LAST RESTING PLACE,
Where they are in turn taken up by the
running waters and transported to their
destination. 1t would seem as if nature
would refuse to supply our rivers with
water sufficient to keep them daily pouring
their billions of gallons of water into the
sea. Change OF temperature, again, is the
agent by whose efforts much of the requisite
water is supplied to the sources of the riy-
eIs. IL 10 tuIouSu It's acLloh tnaG d contln-
uous transfer of water from the lower to
the higher attitudes is maintained. The
mountain tops and high table lands are
colder than the valleys below hence clouds
cf water vapor are continually passing from
the lower to the higher regions, where,
coming in contact with the cold strata of
air, they are condensed and fall as rain or
snow. In these mountains are thus begun
the rivulets which are to end in teeming
Mississippis and Amazons. These mountain
streams cut and wear their way into even
solid rock, and wear out channels for
themselves against whose sides and bot
toms are effectually ground inte every grade
Of fineness the rncks and hn1lders which