The Kenosha telegraph. [volume] (Kenosha, Wis.) 1860-1888, 1869-08-05
ECLIPSES.
Director of Dearborn Observatory, Chicago.)
BY t. II. STAFFORD.

II 1Oiu ILAl6 W tIlu6 ~ Is uOJlCGQ 6I1dI
the sun and moon are partially or totally
eclipsed +; that is to say, in the suns case,
a portion or the whole of that luminary,
as we usually see it, is hidden by a round,
dark body, now we'll known to be the
moon; and III case the N Don is eclipsed,
a dark shadow appears to cross its disc.
We know by observation that. when the
moon is eclipsed it is always full moon;
that the earth is interposed between the
sun and the moon, and that it is the
earth's shadow which produces the
eclipse. Again, when the sun is ,eclipsed
it is always new moon; and we always
see the slight lunar crescent called the
new moon day or two afterwards.
But not at every new moon does an
eclipse take place77only atcertain seasons
OF this kind, when the sun, earth and
moon are unusually near the same line /;
for if the sun and moon be apparently in
conjunction, that is in the same region of
the heavens, but at the same time one ap-
pears SO far above the other that they es-
cape appearing to touch, there will be no
eclipse. And in the same way,if the moon
at its fnll does not pass exactly through
the earth's shadow, it may pass over or
under it, and so escape an eclipse entirely,
Before going any further, it may be
well to state that so-called total eclipse
of the moon does not cause the moon to
disappear entirelyi but even then she
still shines with q, dusky light More Of
this further on. r9dBag o5s rrroEe s..
There are three kinds of eeiipses of the
sun-partial, the eeommonest kind : total,
the rarest; and a third kind, annular,
neither partial nor total, strictly speaking.
The reason of this -kindiwe must think
about for moment. a4e f
We all know that the sun and moon
appear to be very much of the same size
but they are very different in magnitude.
The sun islmueh larger, and about as
much further off; so that, as the pane OF
glass i'll my, room appears nearly as large
as q great. building alta half-mile distance,
SO the sun and moon appear relatively OF
the same size at But it | go nearer the
Window shall see the pane larger pro-
portionably than the building; and pact
oegs0 if I go away from the, window, u II
then, we place the moon at such a, dis
Stance from us, and in such pl4ce, that it
will appear just to cover the sum- and
then approaehnearer, the moon will appear
to grow larger faster than the sun
does, and atotal eclipse will take; place
On the other hand, if we go further. from
the moon, it will grow Ito ps) smaller, and
will not cover the whole sun, but leave a
ring of light outside. And just the same
thing happens, when the centre OF
The sun and moon appear just in the same
place to US that is, when the eclipse lis
"central," as astronomers. d call it. The
moon is IN this case so near as to entirely
cover the sun, sometimes so far as
to leave ring of 4ightaround itself the
eclipse in the first case is called total, in
the second case annplar-oT, as the Ger
mans say, ring-formed. ssI oa4 IL aeiE8ou
When do the ecllpses of the sun take
place ?-that is how can we predict them!
To do this thoroughly and with extreme
accuracy, requires tables of the SUMS, and
moons motions, and great deal of calcu-
lation. Large volumes are, devoted to
the purpose of telling exactly at what
point in the heavens the sun and moon
will be at any future instant, and dc SO
with such accuracy that we cannot ,foa
many years fail by one minute Of time in
predicting when any eclipse will take
place; and when even this degree Of &C.
curacy is reached, corrections will be
made from the results of the daily and
nightly observations now making in all
civilized countries But it is comparative.
ly easy to predict when an eclipse will take
place with some approximation to the
trath, and by two considerations IL 1of B.
First, there are two days in every
year near which a new or full moon is
likely to bring an eclipse. For this yeal
these dates are February 9TH and January
Both and so we fined, by the more re
fined calculation, that there are eclipses
of the moon on January 9th and July
Esd, both these dates being full moons
and Of the sun, February a11th and Au
gust 18th, both these days being new
moons. aF Era .enned 55aI enl
~ Again, every eclipse is followed by "a
somewhat similar eclipse VISIBLE how
ever in a, very different part of the, earth
lat an interval of eighteen years ten
days andaa fraction so that the eclipse
which took place in the forenoon OF July
29th, 1851, will be followed by one.in-tlhle
afternoon of August 18th, 1862 Bat; this
eclipse of 1851, was only partial in in /, the
United States, and total In a, small part
of the nor9herly part Of North America,
and through small belt of conntIy lin
Europe; that of 1869 will be- fetal oaIE
in narrow belt in Northernaya.Aa=s iaa and
North America IA belt Hhichvi rpsSses
through Illinois as will be Re9tleBsd by
and, bysIgif. s'8egial 9 -i,frrsits Il jssEl
s Between these two ecll1sdsi idulgi 1s5hl
and August, 1869. there lave htzHailab5
served about seventy othsB,and it is cal
culated that of these seventy, forty-one
have been of the sun and twenty-nine of
the moon, and eachaSne Of except
perhaps, some of TIE Smaller ij5thes Tffiffl
have Is s sls