The morning news. [volume] (Savannah, Ga.) 1887-1900, 1900-05-13

opaque body of the moon coming between
Us ana the sun and cutting off a portion
or all OF its light. The sun is a much
larger body than the moon. and hence the
moon shadow tapers out into a long
cohlcal point. The length of this shadow
varies Slightly with the distance of the
moon from the sun, but its average length
Is ABOUT $4,000 miles. The mean distance
1 OF the moon from the earth is 23S 800 miles
Dut owing to the eccentricity of its orbit
tnis Instance varies from 221, GA TO 252. 972.
WINE the average length of the moons
SHADOW is somewhat less than the average
Instance OF the moon from us, this sha-
uoW as will be seen, is sometimes long
enough to reach to the earth. Should the
SHADOW then fall upon The earth an OBJ
server within the shadow on the surface
OF the earth would have the sun COM
pletely obscured from view and therefore
totally ecLpsed. Should the length OF the
shadwo not be sufficient to reach to the
earth the moon would not appear large
enough TO cover up the sun, but a bright
ring OF the suns obscured disk would
remain visible. This is known as an annu-
lar eclipse.
The shadow so far considered is called
the umbra or true shadow within which
the sun is totally obscured. The greatest
possible diameter of this shadow on the
cath is l67 miles, ana the longest posi-
bic duration of a total eclipse for any
place on the earth is minutes IS seconds
conditions that are rarely if ever really
attained. Surrounding the umbra like an
inverted cone is another shadow called
the penumbra within which the sun is
only partially obscured. The cross sec
tional diameter OF this penumbra at the
distance of the earth is about 4,4O0 miles
The arrival of this penumbra at any place
on the earth marks the beginning, and it's
departure the end of the eclipse. On the
accompanying map the position of the
penumbra as it advances across the earth
is indicated for every minute by the curv-
ed lines marked begins" and as ii re-
cedes by the curved lines marked ENDS"
The velocity with which the shadow of
the moon passes over the earth is equal
to the velocity of the moon in it's orbit
e, 100 miles an hour less the speed of the
earth's rotation Q,04O miles an hour, for
both the earth and the moon moves from
west to east.
This velocity is often largely increased
by the slower rotary motion of places
nearer the poles and by the obliqueness
with which the shadow strikes the earth.
In the present eclipse the shadow of the
moon will sweep across the state of Geor-
gia in four minutes, at a rate of more
than $500 miles an hour.
Phenomena of Solar Eclipse.
There is nothing of special interest to
be noted about total eclipse until the
sun is nearly covered. For more than an
hour the light is gradually lessened as the
moon steals its way across the solar disk,
but so great is the illuminating power of
even a very small portion of the sun, that
we are surprised at the effect but the
moment the last bit of the sun is obscur-
ed darkness follows with startling rapid
ity. Instantly the air appears to culver, and
numerous bands or "fringes'' of light and
shadow appear to move over white sur
faces upon the ground. A white sheet
spread upon the ground will show these,
and they are among the interesting
things to observe and record. This Curl
Gus phenomenon is not yet suffc entity
explained, but it is probably due to the
diffraction of light.
Just at the moment of totality and
sometimes a little before, the corona and
solar prominences become visible. The
proper observation of these constitutes