Evening capital. (Annapolis, Md.) 1884-1910, 1885-06-17

TAX DIRECT CAUSE nKCx.ARKn~
sUpERnKATHD sTkAM. g
An GmkoronslnR Discourse ExplnSnan.
earthquakes and velcanic ErupsIss


It has neen asked OF late wheths
hurricanes which followed the sn..
earthquakes were not produced bva
sublerranean disturbances, and N
planning electricity has been called,
10 explain how earth-throes might
caused atmospheric disturbance
know ot no way in which such :.
sequences could have followed ircs
displacement Of the earths crust
me il seems far more natural to conel,.
that the hurricanes aud earthop,s
were alike produced (the hurrio,
chiefly, the earthquakes partially
the atmospheric compression which,,
ceded the subterranean disturban.s
This compression indicated heapipo
cir over the disturbed region; theea,s
crust yielded under this increase
pressure, combined with the action
other forces, and earthquakes folIov.s
the compressed cir swept away d {
gions Of less pressure, and the ~
faction following led in the usual way
the indraught which precedes cyOIoss
disturbance il the air.
But while the action Of atmosphss,
pressure ia helping 10 excite sub,e
ranean activities must not be overloOkss
the varying pressure exerted by seas q,
oceans u . more potent disturbiD
factor. Atmospheric pressure is az
tributed II such 9 way that though d
weight OF air on any given area is co..
tinually changing, there are no sharp,
defined lines, at any time, which separas
regions Of less pressure from regions
greater pressure. II i otherwise viii
the sen along . shore line. Here \
have the see acting with constant,
vavying intensity, a. it's level changes
ON the seaward side Of the shore line
while on the landward size there are u
such variations Of pressure.
Let MS consider what this means
Take tolerably straight shore line so
miles in length, and suppose that alcup
this shore line q region Of ocean 10
miles broad rises through hight q
three feet under the combined action &
sun and moon raising q tidal wave, and
favoring strong winds urging the wata
shoreward. Then we have 1000 squars
miles Of sea-water, three feet deep
added as so much lightweight to thai
part OF the earth's crust which upderla
the seas along that shore. Each squaa
mile contains in round numbers 5000.
600 square yards, or 1900, 600 squaa
feet. The additional weight correspond,
then Gas the added layer is three feet
deep), 90, 900 times 81, 900, 900 cubic fest
Of water, each weighing 64a pounds, a
to 116, 900, 600, 900 tons.
lit Is clear that the addition Of 50
enormous q weight as this to the sub
merged part Of the earth's crust, ontsids
the shore line, may we'll produce
strains too great to be resisted. It must
be remembered that the very existenCs
Of 9 PERCEPTIONS shore line (as distin.
guished from one where the land aboys
water and the parts submerged form one
great slope) indicates the comparative
weakness Of the crust along that coast
II has yielded on one side to pressure
thrusting It upward above the sea-leye,
and on the other side to the pressure
Of the water forcing il down. It is true,
the actual line Of yielding may moi
coincide with the existent shore line,
for the action OF the sea waves may
(and generally must) have altered the
position of the cast from that which i
occupied when first formed. But it may
be taken for granted that not far from
every precipitous shore line lies line
Of weakness. whore the crust has given
away ia the past, and may give way
again. In this consideration undoubt.
edIy we find part Of the explanation Of
Che observed fact that almost all The
great regions Of subterranean activity on
The earth lie near the sea-shore.
But while the changes Of the atmos.
pheric and oceanic pressure are potent
factors ii the production Of earthquakes
and ere probably IN the great number d
cases their direct occasion, 1t Is, o
course 70 the subterranean regions them.
selves that we must look for the forces
at work IL npheaying the crust Of the
earth. The forces acting from the ont
side are ct the pull on the trigger; tht
Imprisoned gases and vapors generated
BY internal heat are IS the powder BY
whose explosion the missile il elected.
Yet even ii considering the earthi
subterranean activities we still have Z
look outside for . part at least Of thl
causes 81 disturbance. The air ma.
perhaps IA this respect be neglected
but the water i all-important. 1t ha
been said indeed, and probably with
nearer approach to truth than usual d
the case o. congratulations Of the sort
without water there can be no vol