, 1888-03-10
Utility OF N
Tho PuIverized Material Which They
Throw Out of Value to the Soil.

1hc IulVerized Material Which They
Throw Out of Valuo to the Soil.
The solid matter thrown out by vol
canoe is the most important contribu-
ton to the materials which the sea has at
its disposal for the nourishment of its
life and for the formation of strata. The
quantity of the pumiceous and finely
pulverized material is When
it falls upon the sea it either floats for a
time or at once sinks into the depths. In
either case it is, to u great extent, dis
solved in the ocean waters, and so con-
tributes to the store of materials which
may be appropriated by the organic life
of the sea. When it falls on the land, it
is generally so incoherent that it is easily
swept away by the rains, and so comes
quickly into the ocean. The importance
of this contribution to marine sediments
has been overlooked by biologists, but it
is easy to see that it may amount in mass
to something like as much as the earthly
matter which is brought to the sea by
the rivers.
The volcanoes of the Java district alone
within n century throws out a mass of
his ragmentary rock amounting proba-
bly, to not less than 100 cubic miles, and
perhaps to twice this quantity. Now, the
Mississippi river carries out in the form
of dissolved matter, mud and and about
one cubic mile in twenty years, or five
cubic miles in a century; thus these vol
canoes of the Java district have brought
up from the depth of the earth and con-
tributed to the sea many times as much
detritus as has been conveyed to the
ocean by the greatest river in North
America. Allowing for the greater poros-
ity of the volcanic dust, it still seems not
unlikely hat the elections from a half
dozen great volcanoes of the East Indian
archipelago, i'll a period of a little more
than a century, from 1772 to 1888, far
exceeded that brought into the ocean by
all the rivers of North America in the
same period.
Although the volcanoes OF this district
are by far the most powerful which are
known, we still cannot fairly reckon that
their elections represent anywhere near
the half of the total quantity which came
to the earth's surface from such vents
during the above named period of III
years. For during this time some scores
of great craters were in eruption, includ-
ing Skaptar, in Iceland, Vesuvius, Etna,
various volcanoes in South America and
elsewhere. 1t seems, therefore, not I'M
likely that the solid material contributed
pl NOiNallOto W LilC Z llOOl Lld VII lilt
average, amount to as much as that taken
by the rivers from the land.
Among the solid substances which are
elected by volcanoes we find some of the
most indispensable elements of organic
life, including phosphorus, soda, potash
and other materials. The value of these
materials to vegetation may be judged
by the fertility which so often character
ICES the regions in the immediate vicinity
of volcanic cones which cast forth large
amounts Of ash. If the rainfall be suffi.
Gent this ash quickly decomposes into a
fertile soil, which tempts the husband.
man to replant the fields as fast as they
are ravaged by the explosion. Were it
not for the constant return of these
rarer and precious materials to the su-
perficial part of the earth by means Of
volcanic action, it is likely that the
earth's surface would want many of the
substance most necessary for organic
life. We thus see that volcanoes play a
very important part in the physical his
tory of u planet. The action is, in q
large degree, restorative. They help to
maintain the earth's surface in a condi-
ton in which it may nurture life.-Cin-
cinnati Commercial Gazette.