Orleans County monitor. [volume] (Barton, Vt.) 1872-1953, 1907-12-16
LENGTH OF THE DAYS
Difference Between the Star Day
and the Sun Day.
1T IS GREATEST IN WINTER,
Why the Difference Occurs and How.
1t May Be o5served-Oddly ENOUGH
the Shortest Day In the Year Is
Really the Longest Day In Time.

really the Longest Day In Time
How long. after all. is a day? The
! Biographies say that it 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 a fraction
, more than 800 of them are to be found
in year
1t is a good plan when one reads
anything in book TO test it when he
can for himself. We want to see lust
how long it takes the earth to turn
over once. Let us take any one of
the fixed stars that chances to be in
| line with some convenient point and.
watch in hand, notice the precise mo-
ment at which the star touches. LET us
say. particular tree. branch or stee-
pie on the horizon line. If on the next
evening we stand Al precisely the same
spot and sight the same star again in
, line with the same point as before,
then we shall know that the earth has
turned OH its axis just once.
Curiously enough, however, we shall
discover if this is done carefully that
in spite of what the books say, it does
not require twenty-four hours for the
earth to turn over once. About four
minutes before the day is up, by the
clock. the earth has revolved once and
brought the star back to its old posi-
ton in the sky. Really. then, the earth
turns on its axis once in twenty-three
hours, fifty-siX minutes and four sec
ondS and. as one can easily reckon.
makes something more than 366 reyo-
lutiOns in Il year
But human beings are mot so much
interested in the stars as in the sun.
We really don't care much how long it
takes the earth to turn over and bring
a star back again to the same point i'm
the sky or how many times in a wear
star seems to 90 by. We set our
clocks and reckon our year by the
turning Of the earth under the sun.
and because the earth not only turns
under the sun, but also goes round it.
1t takes about four minutes longer to
bring the sun up to its old place in
the sky lhaIfto bring back a star. This
comes about simply enough Suppose
one is in a room looking out the win
dow at tree. If he turns round once
exactly he will find himself lookin.
straight at the tree again, but if he
tried the same thing when he was on
a moving train he would find that
while he was making the turn the tree
had fallen behind. He would then ac-
corGing to the way he twirled, have to
turn a little more or q little less to
bring the tree>straigllt before his nose
Therefore it is not quite true that a
day is the time required for the earth
to turn once on its axis. 1t really is
this time plus the four minutes or so
required for it to turn and look back
, at the sun The time required for this
extra turn is not the same at all times
in the year. One 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 to shift its position.
Since the earth is some 100000 miles
nearer the sun in winter than in sum-
mer. and since also the nearer the sun
1t is the faster it travels. the difference
EetWeen star day and sun day is
greatest in winter.
Oddly enough. it happens that Dec.
%. which has the least daylight Of
any day inethe year and is therefore
commonly said to be the shortest of
all days. is really the longest. 1t does.
as matter of fact. run almost half a
minute over twenty-four hours, While
the true shortest day which comes on
Sept. II, 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
| six minutes, four and nine-hundredths
seconds. and there are 3G6 of them in
! year Then there is the ordinary Ie-
! gal day, which is the time required for
Il proper clock to 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 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