, 1877-03-16

A CLOCK IN THE SKY AT SIoHr.


land which have clocks showing the
time with only one hand-the hour hand
/ dare say that il will seem very strange
10 active and busy minds in America
that such clocks rs these should still
continue in existence. A Slumberous
place it must be, truly. where men are
content TO know time by the hour, and
to take no note Of minutes. Or. IL that
is not really the way Of il. still It must
he strangely backward world where
such clocks, once sufficient for their
purpose, have not yet been replaced by
time measures better suited to active,
business-like folks When such clocks
were more common, and households
and watches less used land probably
very seldom in Order), it would have
been useful to know what | am now
going to tell you about a clock in the
sky, though at present the knowledge
will help rather to teach young folks
the stars than 10 show them how to
learn the time from the stars; for the
clock / have to describe has only one
hand, and not only SO, but that hand
goes the wrong way round, and only
once round in O day.
| LUG uIoI blCD kOnOlN u hAOMlCukO Vi
the stars should be the recognition of
the pole-star, because the pole of the
heavens being the point around which
all the stars are seemingly carried, 80
Lsoon as we know the stars around the
pole, we have a center, so to speak, from
which we can pass to other groups until
we know them all. Once known, the
pole-star can always be found by the
learner, supposing he observes the
heavens always from the same station
for it always lies in the same position
Tor so nearly 80 that the change can
scarcely be noticed.) If, for example,
you have once been shown, or have
found out for yourself, that from q GER
tain spot in your garden, or from a GER
tain window in your house, the pole
star can be seen just above a certain
chimney or tree, then at any time, on
any night when the sky is clear, if you
betake yourself to the spot, or look
through that window, you will see the
pole-star over its accustomed chimney
or tree. 1t is there, indeed, all the time,
whether the sky be clear or cloudy,
whether it be day or night. Not only
does knowledge Of the pole-star give
you a known central-point whence to
others, but it gives you the means Of
knowing where lie the cardinal points
round the horizon; for, Of course, when
you face the pole-star, the north lies
before you, the south behind you, the
east on your right, the west on your
left.
But to find the pole-star, it is well to
begin with the dipper. This we'll
marked group includes two stars which
are called the pointers, because they
point to the pole-star. r.ne dipper is so
conspicuous and well-marked q group
that it is easily learned and cannot easily
be forgotten. Although not very near
the pole, it is yet not so far from It as to
range very widely over the heavens;
and if you look toward the north at any
hour Of any clear night, you will seldom
require many seconds to find the familiar
set of seven bright stars, though at one
time it is high above the pole. at another
close to the horizon, now to tho right Of
the pole, and anon to the left In Eng
land the dipper never sets; it America
it partly sets, but still can be recognized
Except at stations in the most southern
States) even when partly below the ho-
rizon.
In order TO see the dipper in its diff
ferent positions, and also in that portion
of its course which in December it
traverses during the daytime, it is not
necessary to keep a long watch upon
the group, or to study the heavens dur
ing those "wee sma' hours ayont the
twal" wherein the professional astrono-
mer does the best part Of his work. If
you come out in the evening (say at
about 81 once or twice o week on clear
nights, all through the winter half of
the year, and a little later during the
summer months, you will see the dipper
and all the polar groups carried right
round the pole. For though, speaking
generally, It may be said that they com
plete circuit once in every day, yet in
reality they gain about four minutes
motion in the twenty-four hours, and
thus get further on little by little night
after night-gaining an hours motion
in about fortnight, two hours motion
in q month, twelve hours motion Tor
half the complete circuit) in half year,
until finally, at the end Of the year, they
have gained o complete circuit.
It is because Of this steady turning
motion or rotation around the pole Of
the heavens, that the stars Of the dipper
(say, for instance, the pointers) form as
1t were q clock in the sky. by which the
astronomers at any rate, though also any
one who Is willing to give . little attsn-
ton 10 the matter, can tell the hour
within few minutes on any night in the
year.
A few observations made In this vay
on few nights during the course Of the
year, will give q clearer idea Of the