The World. [volume] (Martinsburg, W. Va.) 1891-1896, 1893-04-21
REGULATING TINE.
An Electric spark Sets All the Mig Clocks
In the Country and Tells Us when
II IL MOON In wash
fnRton.


city Of Washington Is a wooded hill
overlooking the Potomac, and forming
part Of large government reservation
or park. which reaches down to the
rivers edge On the top Of this hiIi,
remote from AL the other public build
ings in Washington, stands tho United
States naval observatory.
This branch Of the navy department
Is Of great service TO the government,
and plays = very important parEin the
daily Affairs Of the country; for II Is
here that standard government time Is
reckoned for the use of the depart
ments. and for the primary purpose Of
testing and rating the chronometers
used on the United States war vessels,
and Il Is from this observatory that
standard time i regulated all over the
country.
Precisely at noon each day Il sends out
IN electric signal to the various govern
mont Offices and buildings throughout
the District Of Columbia, and, BY means
Of the telegraph, this same signal Is
flashed over the United States al the
same instant
In order that this signal NAV be
sent out at the right time, II Is necess,
sary that the officers in charge OF the
government time service nt The OBJ
seryatory should know at Just what
instant the sun crosses tho seventy
fifth meridian, or IS directly above the
meridian seventy-five degrees west
longitude, which, as yon have learned,
Is one Of number Of imaginary lines
stretched from pole to pole across the
earth's surface, and reclxuned accord
ing 70 their distance east or west from
Greenwich. Now. this seyenty-ffth
meridian has been chosen as the stand
ard for regulating time, so that when
the sun gets exactly over that line II Is
twelve o'clock at Washington. eleven
o'clock at Chicago, ten O'clock at Dem
yer and nine o'clock at San Francisco;
for, as y on perhaps know, according To
this system of standard or railroad"
time lit being originally adopted for
the convenience Of the railroadsj the
country Is divided into four sections
Eastern, Central, Mountain and Pa
cific-each just one hour In advance OF
the other, and time at oil places in the
same section Is the same. Accordingly,
when Il is noon at Washington ii Is also
noon at Philadelphia, New York, Bos-
ton and every other place included
within the eastern section. This, of
course, IS not strictly correct. for 1t is
really noon at, only such places
through which the seventy-fifth merid-
ian happens to pass. us the true noon
day Of place is when the sun Is direct
~ overhead Washington, for example,
Is on the seventy seventh meridian, or
two degrees farther west, and, conse-
qnently. according to its local time Il
Is only eight minutes Of twelve, while
the true time Of Boston, which is four
degrees to the east, is sixteen minutes
In advance. But II every city were to
use its own time, it would, in many
eases. give rise TO good deal of confu-
sion and Inconvenience; and it was for
the very purpose Of avoiding this that
the present system Of standard time
was adopted.
As we have seen, the time for send
ing out the noon signal from Washing
ton Is the instant the sun crosses the
seyenty-tifth meridian. This, however,
Is not the sun which gives us light and
heat, but an invisible. imaginary one;
because, for certain reasons, the true
sun does not cross the meridian at the
same moment every day, but during
one part Of the year he gets over 1t a
little more ahead Of time each day, and
during the other part he is correspond
ingiy behind time; and so this fictitious
sun is used. because its apparent path
around the earth brings it exactly over
the same line at the same moment
every day. Now at just what instant
this sun crosses the meridian Is deter
mined by means Of the stars; for time
at the observatory is not reckoned by
the sun, but by the stars.
Every clear night an astronomer at
the observatory looks through a large
telescope for certain stars which he
knows must cross a certain line at GER
tain times, and by the use Of an cleo
trical machine he makes record of the
time each star passes, as shown by o
clock which keeps sidereal or star
time He then consnlts printed table,
which shows him al just what time
each star must have passed, and by as
much as this time differs from that re-
corded by the clock the latter is wrong,
and in that WAY the sisicreal clock IS
regulated. This stAr time il then re-
dnced II snn tita wtith requires some
& ealciIla,a, as lss( Il difference be:
twcen te t f5ur minutes
c;sdA daT. 2 Ya.t7 eSasisting 81
j .iia y 81 lar year.
t %neigs tlAa one keeping