Evening star. [volume] (Washington, D.C.) 1854-1972, 1897-07-24

north the observer is.
Something Uncnnny About 1t.
A partial eclipse Of the sun is a far less
interesting occurrence than a total eclipse;
still solar eclfpses are not presented to US
with such frequency that we can venture
to be captious or refuse or this occasion to
give to the spectacle Its due tribute of adj
miration. simply because it is not the finest
OF It's kind. Colored glass and smoked
grass Will be In demand. Millions of ewes
VII! Watch the slow encroachment Of the
invisible lunar disk upon the brilliant disk
!; OF the sun. Even for those who understand
1ully The cause of an eclipse there is some
thing uncanny in this partial blotting out
OF the sun at broad MONDAY at a time
When, TO all appearances. its path through
the heavens is entirely free from obstacle
or Underwent. 1t is not to be wondered at
Z .hat tne occurrence SHOULD be terrifying to
the ignorant and superstitio,ls. A solar
eclipse Is one of those celestial terrors of
which science, happily, mas relieved the
civilized nations, though the savage still
sees il 1t the effort of demon or dragon to
devour the glorious sun-god
among the thousand and one questions
which Will occur to the eclipse observers
the most perplexing, perhaps will be why
the area over which the eclipse is visible
should be limited, since the sun will be Wis
1ble at the time one entire hsmis-
phere of the earth, and why the eciipsed
sun should appear differently to observers
III uHieIeHt localities. Inc diagram given
mere Will aid in answering these questions
An eclipse of the sun is quite different
affair from an eclipse of the moon. A lu-
mar eclipse is caused by the passing Of the
moon through the earth's shadow. 1t is
visible from every point on the earths
surface from which the moon itself is WIS.,
1ble at the time; that is, over one entire
hemisphere Of the earth. Furthermore, a
lunar eclipse, whether total or partial, pre-
sents one and the same appearance to
every observer, no matter where he Is sta
toned, whether in Boston or San Francis
CO or Rio Janeiro, just as the shadow of a
tree cast upon house appears the same
from whatever point of view it is looked
at. A solar eclipse is caused by the pas
sage OF the moon between us and the sun.
10 see 1t one must be situated that the
range Is right. just as to see distant house
exactly behind some near object, as a tree
one must SO stand that the tree is exactly
In line with him and the house. If he
moves from this lire, to the right or the
left, the tree changes its position with ref
erence to the house. and when he has
moved to a certain distance 1t ceases alto
gether to range with the house.
A Simple Explanation.
In the case of solar eclipse the sun is
the distant house; the moon Is the tree
Since this moon is a comparatively small
body, only about 1900 miles in diameter,
while the diameter of the earth is nearly
5000 miles, there is on the earth ample
room for getting of the range when the
moon Is passing the sun. Thus, to an OBJ
server situated next Thursday anywhere
on the twenty-ive-mile line above located,
say at Havana, the moon will appear to
pass directly across the suns face its CEN
ter moving along the line marked on the
diagram Moons PATH" in the direction in
dictated by the arrow. One circumstance
only will prevent the eclipse from being to-
tai for that observer, and this is that the
neon: being now at very nearly her great
frnv fhn ortI, h,
size Is at its least and is less than that of
the Sun. This eclipse therefore has no
especial interest for astronomers, who con-
Germ themselves nowadays with total
eclipses.
For an observer at Washington the range
will be different. To him the moons center
Will appear to pass along the line marked
ABB SO that its upper limb will Just reach
the suns center. An observer in about lat
ftude So will be still farther off Of the
range. To him the moon, could 1t be seen.
would seem to move along the line CD. Its
Upper edge would just Craze the lower
edge of tie sun in passing, and there would
be no eclipse. Much less could there be an
eclipse for an observer still farther north
By No Means Infrequent.
1t is a rather curious fact that, though
we are less often favored, in any particu-
lar locality, with solar eclipses than with
lunar, the former are really the more fire.
quent. An eclipse, whether solar or lunar
can occur only when the moon is, at the
time Of the new or the full" within a
certain short distance of one of the two
points at which her path crosses that of
the sun, and the adjustment of things is
such that at least two solar eclipses must
occur every year and four may occur with
In single year, visible in some parts of
the earth. while an entire year may pass
the present, for example-without the oc-
currence of an eclipse Of the moon.
In the last eighteen years there have
been fOr1v-tw0 eCliDsRS ~ tr fxye.v,
ty-seven of the moon. OF the solar eclipses
eleven only were visible III any part of the
United State. OF these eleven The most in
teresting were the eclipse Of March 3, 1856,
which was annular along a line running
from the west end of Lake Superior south
TO the mouth of the Mlssiss1nui river and