Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-12-29

clock says is simply considered the
time; New Year day seems the nat
ural and absolute beginning of the year.
In reality time is an unbroken stretch, which
man has marked OF in logical but arbitrary
divisions.
New Year day, for US, is a division of the
calendar. There is no seasonal change to
make it fitting The year could begin, as ap-
propriately for any division made by nature,
in December or July.
Some primitive people have no beginning Of
the year, others start the list of months with
the first day of the dry season, rainy season
or harvest. Tribes of American Indians have
New Year festivals at harvest time in August,
or at the time of the first snowfall. Eskimos
begin the year when the sun has reached the
lowest position, at the Winter solStice.
The beginning of the year in our sense,
however, is merely the starting point of the
series of calendar days. When the calendar
was in the process Of repatriation, the month
with which reckoning was begun became auto
matically the first of the year. This beginning
point, like other questions of time, is linked
with observation of the stars.
THE time that we plan our lives by the ordi-
nary familiar time that is used for boiling
eggs and catching trains, is calculated directly
from the stars. Clocks and watches all over
the country are checked by the radio time
signals sent out from the Naval Observatory in
Washington and the standard time kept by the
observatory is in turn checked by sideral or
star time.
Three master clocks are kept at the observa-
tory in an underground vault, under uniform
temperature and air pressure, never disturbed
except for repairs. These keep sideral time.
BY electricity the time is transmitted from
them to the time room from which the radio
signals sent.
The time signals are automatically sent out
by transmitting clocks. The time registered by
recording OF the master clocks and with Green
wich time
Radio dashes are sent out on each second,
for five minutes, at ass am, 11:55 am. and
9:55 pm. Eastern standard time. The twenty
ninth second and the flftieth to sixtieth seconds
are left blank to identify the end of the half
minute minute.
The signals are sometimes thought of as
coming from Arlington or other radio stations.
In reality, they come directly from the time
room at the observatory. The transmitting
clock sending the signals stretches a long tele-
graphic arm to Arlington and Annapolis and
the two radio stations are under temporary
automatic control Four other stations, at
Great Lakes, Key West New Orleans and San
Diego, transmit the Naval Observatory signals,
received through Western Union lines.
The observatory signals were first sent out
90 that navigators could check their chronom-
eters before leaving harbor Now they are
used all over the world Byrd receives them at
Little America and they are used by surveyors
in Alaska.
THERE are three kinds of time in use, or
= three ways Of measuring time Sun time,
or local apparent solar time is told by the posi-
ton of the sun In relation to the earth This
can be read by sundials. But because of the
Hregularity of the earths motion in its orbit
apparent solar days vary in length and thus
the time is not constant.
Sideral time Is used by astronomers and Is
an accurate basis for checking. The exact
times at which certain stars are in certain
positions is observed; the correct time Of pass
ing those positions is known by previous rec
ords and calculations; thus comparison be-
tween the known time and the time recorded
by the clock during the observation shows any
error Of the clock. Sidereal time may be con-
sidered the perfect abstract time, because the
stars are so many light years away that their
variation cannot be detected.
The time that is in ordinary use is mean
solar time. This is an average time used so
that all the hours can be precisely the same
length. There is a variation between apparent
tire and mean time, that at its widest point
is Is minutes. What is generally considered
time, then is neither measurement by the stars
nor accurate measurement by the sun; 1t is a
popular rendering OF time, averaged arbitrarily
for convenience.
A NEW method of determining time has been
discovered by Capt r. b. Littell and J. e.
Willis of the observatory This method is be-
ing practiced satisfactorily now and after few
minor corrections 1t is hoped to be put in use
this Spring.
The method is based on pictures taken of
the stars by Photographic telescopes It is an
adaptation Of the Photographic reflex zenith
tube, now used to find variation of latitude to
the determination Of time.
Photographic plate is used which is sta
tionary in the east-west direction The image