New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1906-01-21
SUNDAY MAGAZINE for JANUARY Fl. 1906

tai and moral nature OF the inhabitants
study of various seisnOgraph records
shows that an earthquake always manlfeStS
itself as vibration, partly horizontal ana
Dartly vertical The ratio OF the dis
placement averages about SIX to one
The extent of the movement IS surprising
tv small Thus a horizontal vibration,
when the displacement amounts to
tenth of an inch, is easily noticeable
If it reaches half an inch, it is dangerous,
while if it reaches an inch, shattered
chimneys and walls are sure to result
In several earthquakes the motion may
perhaps equal a foot These distances
are all measured at the level of the sur
face of the ground. At the tops OF build
inps the amount of motion IS greatly IN
creased. | myself have seen the iron
cross on church sPire swing through
range that was estimated at about SIX
inches, and yet the shock was not a severe
one, little damage being done.
The speed with which earthquakes are
transmitted varies greatly, depending
chiefly on the character of the soil, but
also somewhat on the intensity OF the
shock, violent earthquake being trans
a mild one The velocities actually OBJ
served in different cases range all the way
from about a mile to nearly ten miles a
second. The latter figure was derived
from observations made between Chile /
and Japan, and should be somewhat re-
duced if it is the fact, as appears to be, !
that the shock is actually transmitted
through, instead Of around, the world.
Although transmission through the
earth seems to be possible, it is yet clear
that earthquakes never originate near
its center; otherwise they would some |
times be felt on the opposite sides at
nearly the same time. Similarly we
find that they never originate at great
depths. such as five hundred or one thou |
sand miles. 1t is improbable that the !
depth of the origin ever exceeds thirty |
miles In certain cases it is more likely to |
be at depth of only few thousand feet, |
We now come to a curious class OF |
observations, when bodies, such, for
instance, as lamps, are projected YER
tically out of their sockets. After the
great japanese earthquake of 1891 it .
was found that certain large gate-Posts .
had shifted their positions by a series OF .
jumps, each jump measuring from one
to four feet. The original position of the .
gate-posts was well marked, as were also .
the impressions on the ground where they
had temporarily landed. Perhaps the
most surprising statement of this sort we
have on no less an authority than that of /
Humboldt, who tells us that during the
great earthquake of Riobamba, Ecuador .
in 1907, bodies were projected verti-
ca1ly one hundred feet into the air
This statement probably refers to sand
and mud, which together with hot water
and gases are sometimes expelled from
earthquake cracks as from a volcanic
crater. The sulphuretted hydrogen
emitted at such times from the bottom
of the harbor of Callao Peru, is occa- /
sionally sufficient to blacken the white
paint of the shipping. This phenome-
non is locally known as the painter 1t
is said that in some earthquakes such as at
Lisbon, flames have risen from the ground.
Several investigators have endcav-
ored to find some relation between earth I
quakes and the position of the sun and
moon. There is some evidence that