Audubon County Republican. [volume] (Audubon, Audubon Co., Iowa) 1885-1894, 1892-05-12
VARIOUS KINDS OF TIME.
why tho watch OF Traveller Going West
seems to he Fast.


Turning upon It's axis in tho period
which We divide into twenty-four
hours, the sun appears TO cross tho
meridian OF each place on the globe
once In that interval. The moment
at which II crosses tho meridian OF
any place Is termed local apparent
noon" at that place. This would all
manned fixed In their relative posi-
tons; or II tho earth, completing rs
II does an annual revolution about tho
sun did SO uniformly In perfect cir.
Gle and that circle were In tho same
plano with the motion OF daily rota-
ton Then the successive intervals
between the meridian passages OF tho
sun ut Greenwich would all be- equal
and u perfect chronometer set ut II
hours, 0 minutes, 0 seconds. whom tho
sun passes tho meridian today would
indicate precisely the same instant
for apparent neon" every day.
But the earth's path around tho sun
Is not n perfect circle; II Is an ollipso
and tho motion In ono portion OF tho
ellipse is moro rapid than in another.
causing slight variation In tho in
tervals between tho solar passages
Again, the plans OF the earth's path
around the elliptic Is inclined
PA degrees to the plane OF tho equa-
tor In which the daily rotation takes
place, and consequently twice year
tho intervals OF apparent noon" are
/ Ia.
ind twice u year about twenty seconds
loss than twonty.four hours To OK
plain just why this result would ro.
quiro moro Of mn Investigation into
Astronomical principles than Is here
contemplated. but IL Is 40 noverthe,
less and any text book will olucidato
tho reasons A combination OF tho
J two effects causes the sun apparently
! To slow fourteen minutes In NOyem.
Dor But In tho course Of year tho
average Is preserved, aud therefore 1,
mean solar day OF exactly twonty-
four hours Is adopted In tho almanacs
and IL used for MI purposes This
accounts for the differences between
mean tlmc aud sun Time. A regulators
keeps the former; II sun dial indicates
| tho latter.
| A fow yonrs ago every largo city in
tho United States had It's own loca
| time. says the san Francisco Exam
iner, and this was for each place the
truo moan solar limo obtained rs
above indicated. Consequently II man
travelling westward from Washington
would find his watch fast rs follows
| Az Chicago - minutes; nj Omaha,
hour. Ii minutes; at Denver. hour
81 minutes; ~ SILT Lake City hours.
20 minutes and iinall y NJ san Francis
co 3 hours ? minutes II will readily
be recalled how much annoyance both
to truinmou and travellers was Gee u,
stoned by all those various corrections
Within the last decade u great reform
was inauguratod, To-day traveller
going westward finds his watch fast
from t,mo 10 time but only tho hour
hand Is In error Tho hour Is changed
for each fifteen degrees OF longitude.
Washington time IL five hours slow Of
Greenwich; Chicago six hours; Den
yer, seven hours; and san Francisco
cities and towns are run on ono sys.
tenn or tho other according TO thcil
location In latitude, tho standard bo
ing Eastern. Central mountain ano
Pacific time All tho time-pieccs OF
the coast are set by Pacific standard
time, which is eight hours slow o
Greenwich mean time. Therefore I
watch which il set mt San Francisco
solar time by means OF n corrected
sun dial Is still minutes ~ second,
slower than u Pacific standard time
because We arc that much in longltud,
west Of tho l2Oth meridian which
forms the eastern boundary OF North
ern California and on which only Il
tho Pacific time coincident will
local mean time"