The Grenada sentinel. [volume] (Grenada, Miss.) 1868-1955, 1911-08-04
TIME BY MERIDIANS
ARRANGEMENT THAT MAKES
THE COMMON STANDARD.
System Dates From 1888, n MAJ
Devised to Meet the Require
ments Of the Railroads.
Explanation is Simple.

The measure of any circle. includ-
ing the circumference of the earth. OF
course. is $50 degrees. The earth re-
wolves on its axis once IN "a hours'
hence the sun appears to pass oven
one-twenty-fourth of the circumfer-
ence of the earth in n hour. 1t Is
always noon at some point on the
earth's surface, and of course at a
point halfway around the earth, II is
midnight. The extension OF the rail-
way systems of the United States,
which cover nearly 60 degrees OF
longitude, caused all kinds OF trouble
because of the difference of time. 1t
is noon by the sun at n point on
the earth's surface when the u IS
directly over the meridian of that
point-that is, 1t Is noon by sun time;
but nobody runs by sun time. Why?
Because the movement OF the eartn
in it's orbit is faster In winter h
in summer: so that the time common
ly called "sun time." at each city, is
not sun time, as by the
minute the sun reaches the meridian
of that point; but, what is called
mean time" which is the average
time throughout the year that the
sun would be on the meridian If the
motion of the earth were absolutely
equal at all points in its orbit.
The more the railway business OF
the country increased, the greater be-
came the trouble. So, in 1883, the
system called standard time" was de
: vised and adopted by all the railroads
in the United States. The plan-and
a remarkably wise one-was to des
ignate certain meridians, l. degrees
apart-and where the difference II
actual sun time would, Of course, b.
exactly one hour-and have the tim
. be the same for a space of country
of which these meridians should b
the middle.
Dr. The first meridian is that Of rs d.
" grees west of Greenwich. This lin
ee passes Just east of Philadelphia. Fo
y. seven and one-half degrees east an
IN west of this, the railroads keep whs
is known as eastern time" III
next meridian is that Of 80 degree
rs. west Of Greenwich, which pass'
ie' through Wisconsin. eastern Iowa ar
ny close to Memphis. This is GALE
central time" The next is tt
d. space, is degrees wide. of which Il
On meridian of 1O5 degrees west
Greenwich is the middle. That mer'
ian passes through the eastern edg
on Montana and wyoming, and j,
west of Denver. This Is call
ms umouptajn time" The next finest
has its middle on the meridian
the 120 degrees west of Greenwich, VIII
$50 passes through Washington, Ores
by and California. This is called "Pf
fc time"
10 For instance, suppose n is tra'
ing from San Francisco east, and S
90 his watch in that city. Suppose
comes east over the Union Pacific.
90 Ogden, which the railroad has M
the point Of timedivision, he sets
10 watch an hour faster. At Cheyel
Mills, Colo, he sets 1t an hour ia:
40 again, for the changes from noun
'.35 to central time. He reaches Chici
100 and goes east over the Lake Sh
- At Buffalo he sets his watch one I
LIZ faster, that being the dividing ?
II. between central and eastern t
When he does this he finds his W;
agreeing with the time of the pl
through which he passes, and
,ndi- the railway tlmecards. IL ne traV
year westward, he would Simply set
d in watch one hour slower at the I
bust. named.