Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1902-05-29
Talk on West Indian Eruptions
by Noted Geologist.
History and Cause Of Outbreaks Traced
-Earth's Centre Not Molten Fire
The Globe Solid, with Fiery
Spaces-Enormou Pressure In
the Interior-1ntense Heat
as Shown by Borings.

V,
Peice in Martinique and La Soufriere IN
St Vincent. The steaming cones OF
AETNA were always before the anclentS'
and Vesuvus has been known FOR nun
dreds of years 1t is said by some that ST.
John received his inspiration for the BOOK
of Revelations from the volcanoes near
the island of Patmos. OF the mysterious
phenomena which involve the earth's heat
none has been so appalling in its effect as
the recent catastrophe at Martinique. Tho
eruption which destroyed Pompeii may
have slain more people, but the dearth
of communication at the time made its
effect far less serious on the world at
large.
volcanoes are connected with the in
terror heat of the earth. If we descend
toward the interior of the earth we find
that a thermometer will rise one degree
for every 40 feet in the descent. At the
Gepth of a mile the increase of temper
allure is IS degrees. and for 80 miles II
would be almost 5000 degrees The tenn
pcrature of molten lava is about goo de-
rrces Fahrenheit Experiments in differ
.nt parts of the earth show the increase IN
temperature of one degree upon descent at
different depths as follows:
Feet.
Superior copper mines ..........."..S to ~
Pittsburg shafts ACKNOWLEDGEMENTS. w
Well at Irktusk. Siberia..... ............ VI
Switzerland shafts ...................'..'. %
"A hole drilled in the Comstock Lode
gave forth water at the heat of l7o de-
srees. The geysers in Yellowstone PARK
get their heat from old reservoirs or lava
which have not yet cooled.
Early biologists were greatly impressed
by these facts and reached the conclusion
that the interior of the earth was molten
mass covered by a crust of from 20 To o)
miles in thickness. This theory is no longer
lenable. The item of pressure has an i'm
portant influence on the fusing point OF
rock. and hence on volcanic action AL
one mile beneath the earth'S surface there
Is a pressure of 5000 pounds to the square
inch; at % miles it is 5000 pounds, and at
10 miles about 100000 pounds or liz tons
As we descend the pressure increases
RAPIDLY, and under these circumstances the
fusing of rock is impossible. If the earth
had the crust spoken Of the attraction of
the sun and Of the planets would cause
tides Of incandescent material, which
would soon shatter this crust
THE general theory to-day as held by
biologists is that the earth Is solid
throughout There are certain heated
reservoirs far beneath the surface which
give rise to volcanic eruptions Lighter
rocks are thrown up from the comparative
surface. and heavy rocks only appear from
the depths when the volcano is at its dy-
ing stage. But what are the forces which
bring the lava and scoriae to surface! l,
has long been observed that volcanic
eruptions are accompanied by earthquakes
The converse does not hold true. as evil
denced by the great earthquake at Charles.
ton, when no volcanic phenomena
were observed. These earthquake shocks
are connected with the causes rnat pro-
duoe volcanic disturbances. In folded
ridges like the Alleghanies We find no erup-
two rocks. There seem to be great frac-
lures in the earth's crust along the line OF
volcanic upheavals. One begins on the
western coast of South America and ex-
tends along the shore Of the Pacific tC
Alaska, thence to the Aleutian Island;
and TO the East Indies, the scene of the
greatest volcanic disturbances that we
know to-day. Another is found in north
crn South America and the islands Of the
Atlantic. Vents are afforded by these frac
lures to tap off the hot molten lava from
the reservoirs. Sometimes this comes III
IN huge sheets and flows as one mass Owe
the side Of the crater. Fractures may b.
OF long extent or may be small, much lik'
Il safety valve.
potentially solid by the great pressure up
on 1t, although it may be very hot, Whei
the pressure becomes unequal as by tn
sinking of land an eruption occurs. TIN
same thing can be seen by squeezing al
orange whose side Is rent. When the pres
sure is very great at one point the juic
flows out through the fracture. But Their
was no sinking of land in Martinique o
St. Vincent and we look to another caus
for the uphsaval.
EHOIIHONS CLOUDS OIL steam are seen u
volcanic eruptions which are like the nc
lion of an effcrvescent fluid when cor
is removed from the vessel in which It
confined, Then there is the explosion ei
feet which scatters volcanic dust and larg
fragments of rock Later the flow of Law
comes, which is comparatively calm wit
minor explosions. The earthquake theor
affords an explanation. Earthquakes us
nay precede volcanic eruptions. TIL
steam which is pent up in the volcani
reservoirs accumulates behind barrie
Of rock and breaks it away giving rise I
earthquake shocks. This is repeated pc,
iodically until it reaches the surface an
he eruption occurs. This Is the real e>
panation Of the eruption along with tn
idea of the sinking of rock.
The severity of an eruption from
particular volcano depends largely on tn
frequency Of Its outbreaks. If the cone
long inactive the eruption when II come
is Of tremendous effect. This was the cas-
With Nesuvius, which now has been pc
i0dically active since A. D., 70. Before tht
time II is supposed to have had 500 yea,
of quiescence, and when the upheaval can
1t blew out the whole side of the mou,
tain. Mount Pelee has been quiet sine
lI2 and considerable violence could hay
been anticipated from its eruption.
What is the source of the vapor whic
is kept in high tension in the subterr;
mean laval It was noticed that most vo
canoes we. @ near the seacoast and tn;
the water which contains hydrochlor
acid soaked down to the hot rocks al
produced steam which eventually breal
ils way through the volcano. Other gas
such as sulphuretted hydrogen and su
phurous anhydrde were also thought
be produced by this means. This wou
explain the flames seen in an eruption. b
the light generally seen is nothing but II
reflection of the white hot lava on Il
volcanic dust The presence of the con
IN Mexico and in central Asia, howeve
are as far as possible from the seacoast
"The vapors in the lava, 1t thereto
seems have been in them since the LAY
first became constituent part of Il
earth's composition The earth, by Il
nebular hypothesis, was once an inca
descent mass and Is now in a state of r
trigeration. The original heat by anoth
theory, was caused at the time of the 10
nation of the earth as a single mass
the collision of great comets, the impa
giving rise to the temperature which w
stored up in the earth's interior and sor
of which Is still held.
"Vesuvus was at first a submarine VI
cano. Geological examination shows TN
for 600 feet beneath the surface there
sand and shells, then pleistocene, then no
volcanic calcereous sands. then eoce
sands and then cretaceous lmestor
which has never been penetrated by I
drill. The volcano has torn up this lin