The Washburn times. [volume] (Washburn, Wis.) 1896-1976, 1907-10-17
LENGTH OF THE DAYS
Difference Between the Star Day
and the Sun Day.
1T is GREATEST IN WINTER.

Biographies say that it is the time re-
l."n.l for the earth to turn once on
! $ a:.a. that it measures twenty-four
| OUR, " The clock and that fraction
| ora than $50 of them are to be found
| ga year
1t is Il good plan when one reads
MT; Ing in a book to test it when he
! III fer himself We want to see just
Low long it takes the earth to turn
ever 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 at 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 on it's 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-fou hours for the
| earth to turn over once. About four
minutes before the day isAup, by the
clock, the earth has revolved once and
brought the star back to it's 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 $3.50 revo-
lutions in year.
But human beings are not so much
interested in the stars as in the sun.
We really don't care much how long 1t
takes the earth to turn over and bring
star back again to the same point In
the sky or how many times in a year
a star seems to go 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 1t,
1t takes about four minutes longer to
bring the sun up to it's old place in
the sky than to bring back 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 looking
straight at the tree again, but II he
tried the same thing when he was on
moving train he would find that
while he was making the turn the tree
had fallen behind. He would then, ac-
cording to the way he twirled, have to
turn little more or a little less to
bring the tree straight before his nose.
Therefore it is not quite true that
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 were 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
it is the faster it travels, the difference
between star day and sun day is
greatest in winter.
Oddly enough, it happens that Dec.
%. 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. 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 -hundredths
seconds, and there are 366 of them in
year Then there is the ordinary le-
gal day, which is the time required for
a proper clock to get round twice.
This is just twenty-four hours Be-
sides these, there is the sun day, it's
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 a 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 a 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 it is noon for us when the clock
strikes 70 Nevertheless. astronomers