Clarke courier. [volume] (Berryville, Va.) 1869-1997, 1907-11-20
OF THE DAYS
Difference Between the Star Day
and the Sun Day.
1T is GREATEST IN WINTER.

How long. after all. is a day? The
Biographies say that Il Is the time re-
quired for the earth to turn once on
its axis, that it measures twenty-four
hours by the clock and that n fraction
more than 500 OF them are to be found
in year
1t Is a good plan when one reads
anything in book to test IL when he
can for himself. We want to see lust
now long 1t takes the earth TO turn
over once Let MS take any one OF
the fixed stars that chances to be I'm
line with some convenient point and.
watch in hand, notice the precise mo-
ment az which the star touches. let us
say. particular tree branch or stee-
pie on the horizon line. III on the next
evening we stand mt precisely the same
spot and sight the same star again I'm
line with the same point as before.
then we shall know that the earth has
turned on its axis just once.
Curiously enough. however. we shall
discover. II this is done carefully. that.
IN spite OF what the books say. il docs
not require twenty-four hours for the
earth 70 turn over once. About four
minutes before the day is up. by tho
ciock. the earth has revolved once and
brought the star back to its old posi-
ton in the sky. Really. then. the earth
turns on rs axis once in twenty-three
hours. iifty-Six minutes and four sec
onds and. rs one can easily reckon.
makes something more than 500 revo-
lutionS in n year
But human beings are not so much
Interested IN the stars as i'm the sun.
We really don't care much how long IL
takes the earth TO turn over and bring
Il star back again Ia the same point in
the sky or how many times I'm year
a star seems to 80 10y. We set our
clocks ana reckon our year by the
turning Of the earth under the sun.
anu because the earth not only turns
under the sun. but also goes round it.
4 takes about four minutes longer to
bring the sun up 10 its old place in
the sky Than 10 bring back n star. This
comes about simply enough. Suppose
one Is In Il room looking out the win
dow at n tree. II he turns round once
exactly H. VIII find himself looking
straight at the tree again. but II he
tried the same thing when be was on
moving train he would find that
while he was making the turn the tree
had fallen behind. lie would then. ac-
cording 10 the way he twirled. have TO
turn little more or little less 10
bring the tree straight before his nose.
Z Therefore IL Is not quite true that n
day Is the time required for the earth
10 turn once on it's axis. Ii really Is
this time plus the four minutes or so
required Tor IL to turn and look back
at The sun The time required for this
extra turn Is not the same at all times
I'm the year. Ono can easily see In the
case Of the moving train that the fast
er the cars We're moving or the nearer
the track the tree stood the more the
latter would seem 10 shift its position.
Since the earth Is some 100000 miles
nearer the sun IN winter than IN sum
mer, and Siace also the nearer the sun
IL Is the faster il travels. the difference
between star day and sun day is
I greatest In winter.
Oddly enough. IL happens that Dec.
30, which has the least daylight Of
any day in the year and Is therefore
commonly said TO be the shortest of
all days. Is really the longest. It does.
- matter OF fact. run almost half a
minute over twenty-four hours. while
the true shortest day. which comes on
sept. Il. falls short by about the same
( time
So we really have three different
days" There Is the star day. which
is the time during which the earth
turns over once. This. because the
earth spins steadily. is always the
same length. twenty-three hours. fifty
I SIX minutes. four ana nlne-hundredthS
l seconds. ana there are 800 OF them in
q year. Then there is the ordinary le-
I sal day. which is the time required for
4 proper clock 70 get round twice.
This is just tWenty-four hours. Be
sides these. there is the sun day, its
time told by the sundial, which. tax
ing short With long. averages twenty
four hours, but is never found to be
exactly the same length for two DAYS
/ in succession.
There is string OF long days in the
winter, followed by a series Of short
ones in the spring. In the summer the
sun days get long again. though not
! quite so long as in the winter. In the
autumn come the shortest days Of all.
Only occasionally are clock day and
sun day OF the same length. Only
( four times year do clock noon by
the clock hands and sun noon by the
| sundial occur at the same moment.
while. because the long and short sun
days are found in sets. they oftentimes
may be more than fifteen minutes
| apart.
The vast majority OF the people
reckon their time by the sun. But
time for civilized men is time by the
| clock. The days are all twenty-four
hours long. and no matter where the
sun Is il is noon for us when the clock
strikes II. Nevertheless. astronomers
often go by star time, get in an extra
day in each year and have their noon
Iall ar all times of the day or night
E. I. Brewster in Chicago Record-Her-
aid.
1t is kingly act to help the fallen
Ovid.