The Plymouth weekly Democrat. (Plymouth, Ind.) 1860-1869, 1869-07-29

predict when an eclipse will take place
with some approximation to the truth
and by two considerations
First, there are two days in every year
near which a new or full moon is likely to
bring an eclipse. For this year, these
dates are February 5th and July 30th and
so we find by the more refined calculation,
that there are eclipses of the moon on
January 27th and July 23d, both these
dates being full moons; and of the sun
February 11th and August 7th, both these
dates being new moons.
Again, every eclipse is followed by a
somewhat similar eclipse-visible, how
ever, in very different part Of the earth
at an interval of eighteen years, ten
days and a fraction; so that the eclipse
which took place in the forenoon of July
2Sth, 1851, will be followed by one in the
afternoon of August It'll, 1869. But this
eclipse of 1851 was only partial in the
United States. and total in small part of
North America, and througha small belt of
| country in Europe; that of 1859 will be
| total only in narrow belt in Northern
Asia and North America belt which
passes through Illinois, as will be men
TONED by-and.by.
Between these two eclipses, July, 1851 i,
and August, 1859, there have been OBJ
served about seventy others; and it is
calculated that of these seventy, forty-one
have been of the sun and twenty-nine of
the moon and each one of them, except
perhaps some of the smaller ones, will
have its corresponding eclipse in about
eighteen years and ten days after its own
date.
Some one will here say that eclipses of
the moon are not rarer than those of the
sun; but, on the contrary, much COM
moner. On looking one moment at the
subject, we see the fallacy of this.
where in that half of the earth for which
the moon is up at the time of the occur
renee, but eclipses of the sun are only visi-
BILE through smaller space ofcountry. The
great eclipse of this year has its centre in
Alaska it does not extend much south of
the equator, nor great way into Asia it
is in some degree visible over the whole
of North America, and little way into
the Atlantic Ocean and covers about one
fifth of the earth's surface with the va
rious boundary lines of It's visibility.
And when we come to look at the
extent of total eclipse, we see that it ex-
tends over belt of country about one
hundred and sixty miles wide, beginning
in Siberia, thence passing through Alaska,
some of the late Hudson's Bay territories,
a part of DacOtah, most of Iowa, a large
part of Illinois, Indiana and Kentucky,
part of Tennessee, most of North Carolina,
and little of Northern Nebraska, Min
nesota, South Carolina and Virginia. This
belt of totality just escapes the following
important places: Chicago, st. Louis, Gin
cinnati, Indianapolis and Omaha; and any
one will find that belt one hundred and
sixty miles wide, passing between Chicago
and st. Louis, and avoiding Omaha on the
south and Cincinnati on the north, must
pass about in the direction above indicated
by the States mentioned above. And you
can represent, In q rough way, the course
OF the shadow-that is, of the total portion
of the eclipse-by cutting out a slip of
paper of the width of the representative
of one hundred and sixty miles on any
map of the United States, and long enough
to reach from the map position of Beau
fort, N c., TO that of Fort Union, Dacotah.
Place this strip so that the centre of one
end shall be near Cape Lookout, and the
edge shall Just lap over Rock Island and
avoid Omaha. The path Of the eclipse,
however, is somewhat curved, and the
maps themselves distort the shape of the
earth, so that you will not find such strip,
made straight, to give more than very
rough idea of the shadows course. On
the map which l use, for instance, Gin
cinnati and Indianapolis would be thus
included, and st. Louis be left too far TO
the south.
The phenomena attending eclipses are
quite familiar to those who notice such
phenomena, and in general are these:
The earths shadow is seen at the predicted
time to enter upon the moon, first as u
small circular arc, growing wider and
wider, and often of a pea green tint, until,
when the eclipse is large one, 1t is sue
ceeded by deep copper hue, finally over
spreading a great part or the whole ofthe
moon. After this we can see. with good
telescope, not only the general outlines OF
the lunar disc, but also special features,
such as the ranges of mountains, the cir
cular valleys so familiar to telescope OBJ
servation, and the great plains called by
the old astronomers seas" After
while-perhaps an hour or two-the to-
tality ceases and the partial eclipse recurs
and goes off in the inverse order OF phe-
nOmena. The most striking thing about
such an eclipse is the deep coppery hue OF
the moons surface.
Partial eclipses Of the sun are more
exact phenomena for observation; the
indentatiOn which is seen is produced by
the body of the moon itself, and we some
times see the jagged prominences OF the
lunar mountains This, too, IS to be no
ted that every solar eclipse appears at
different magnitudes for different places,
because an observer at one point can see
further around the intervening obstacle
of the moons disc than at another; and,
as will be inferred from what was before
said, the Sane eclipse may be partial at
one place and total at another.
Partial eclipses OF the sun yield In I'M
portance to anDular. In the latter, four
| phenomena are to be noticed: first, the
beginning of the partial eclipse or indenta-
ton of the suns disc; next, the beginning
of the annular eclipse-namely, the form
alton of the ring, where the moon is first
seen completely within the sun, and its
breaking up as the moon rCcrOsses the
boundary of brilliant light: and finally
the end of even partial eclipse. The an
nular phenomena are much more accu.
rately observable than those of partial
eclipse and the formation and breaking
up of the ring are sometimes accompanied
with what are called "Baily's beads"
The rim of light between the moons edge
and that of the sun is, when very narrow,
broken up into points partially discon-
nected, like string of beads. 1t is sup
posed that the jagged points OF the lunar
mountains cause this appearance.
But a total eclipse of the sun surpasses
in sublimity, as well as interest, all other
astronomical phenomena whatever. Dur
ing a space of time never ever exceeding
1 as<,At r..tvx tha