The Sedalia weekly bazoo. [volume] (Sedalia, Mo.) 187?-1904, 1893-01-03
VARIOUS KINDS OF TIME.
why the Watch Of a Traveller Going West
seems tn lie Fast.

y ast.
Turning upon its axis in the period
which We divide into twenty-four
hours. the sun appears to cross the
meridian o. each place on the globe
once in that interval The moment
ut which il crosses the meridian of
any place IS termed local apparent
noon" at that place. This would all
be very we'll if the earth and sun re-
manned liked in their relative posi-
tons: or If the earth. competing" ~
II does an annual revolution pout the
sun. did ~ uniformly in "a pee Get cir
c. and that circle were IN the same
l..gue with the motion u daily rota-
;!rn. Then the successive intervals
between the meridian passages vi the
sun at EIcciwich would ai D: e .ual
and Il perfect chronomct"r -c' at II
.our>. minutes. - second when The
sun PASSES the meridian io.a. woIld
Indicate rrcsi,.i. The same instant
!"- 'appHr:n; II, on every day.
But the tarth'- path around the sun
j. not a perfect circle il j. ~ tiiipse
and the moi .on in one portion uf the
rltip>e . moe rapid than IN another
causing u H.. ht variation Ia tue IN
t,rvals between the solar passages
again the plans of the eartl's path
around the elliptic Is inclined
- degrees 10 the plane OF the egua-
tor. i'll which the daily rotation takes
place and consequently twice u year
the intervals of apparent noon are
each about twenty seconds greater
and twice "a year about twenty seconds
less than twenty four hours 10 eX-
plain just why this result would re-
Astronomical principles than i here
contemplated. but it Is 80 neverihe-
less and any text book will eiucidate
:he reasons A combination OF the
two effects causes the >uD apparently
10 slow fourteen minutes in Novem-
Der. But in the course of year the
average il preserved. and therefore %
mean solar day OF exactly twenty
four hours is adopted in The almanacs
and is used for all Purposes. This
accounts for tn. differences between
mean time and sun time. A regulator
keeps the former: Il sun dial indicates
the latter.
A few years ago every large city in
the United STATES had it, own local
tine. says the san Francisco Exam
iner AID this was for each place the
true mean solar time obtained Is
above indicated. t'onse iuenily man
travelling westward from Washington
would lind his watch fast IL follows:
At Chicago " minutes: at Oma
] hour. Ii minutes: Mt Denver hou.
- minutes; at salt Lake City hours
- minutes and finally at san Francis
90 5 hours , minutes. IL will readily
be recalled boT much annoyance botu
To trainmcu and travellers was occa-
stoned by al these various corrections.
Within the last decade IA great reform
VIA, iDausuratej. To-day traveller
going westward finds his watch fast
from t me IL time. bat only the hour
hand is in error. The hour j. changed
for each fifteen degree, OF longitude.
Washington time is five hours slow of
Grcenw!ch; Chicago six hours; Den
YER seven hours, and san Francisco.
eight hours. All the intermediate
tenn ur the other according To their
Location in latitude. the standard De-
in Eastern. Central mountain and
Pacific time All the time-picces on
the coast are set by Pacific standard
time. which Is eight hours slow of
Greenwich mean time. Therefore a
watch which is set at san Francisco
solar time by MEANS of a corrected
sun dial is still minutes ~ seconds
slower than a Pacific standard time
because We are that much in longitude
west of the 10th meridian which
forms the eastern boundary of North
ern California and on which only is
the Pacific time coincident with
local mean time"
q m1anmLess Bailey