The morning news. [volume] (Savannah, Ga.) 1887-1900, 1899-10-02
TO SURVEY WHOLE EARTH.
TASK IN WHICH MANY GOVERN
MENTS TAKE PART.

and Land boundaries Get Tangled.
How Magnetic Ncridians Constant
" Change and Throw the Needle
Of the Compass Away From the
Trnc North-One Thousand sta
tionS Necessary in This Country.
New York. SEPT. $40 any one who
haS ever seen a surveyor at work measure
Ing ID ton-ucrc field or city iot. the state
mcni hat the whole earth is 20 be sur
vcycd vii be startling. But The govern
mcnts of the great nations including the
United states, have undertaken this mam-
moth TASK i is hoped that il can be
completed i'm ton years. although this is
10y no means certain.
OF course this survey vii not mean any
OF the minute measurements necessary IN
the work which are ordinarily made by
the common surveyor. But without the
great work which is now under way those
minute measurements would not he accur-
ate; and, furthermore, safe navigation at
sea would be out OF The question For the
surveyor and the navigator alike must de
pend upon the compass In order TO get
their directions, without which they can
not work at an. and the compass, con-
trary TO the general idea. does not always
point true north.
On any good navieators a chart of the
Atlantic ocean, for instance, besides the
current routes and ocean steamer paths,
etc, there are white lines running almost
Hike curling snakes. The explanatory ,et-
tering says that along this line the COM
pass variation is so much, on other that
u1lfrb flnnsr that
or less, as the case may be- In other
words, when navigator is in that par
ucuiar part Of the world he may figure
that his compass varies the given amount
from pointing true north.
These lines Of variation are known as
magnetic mcridans. and they are con-
stanty although slowly changing
The geographical meridians are station
AIRY and always run true 10 the two geo.
graphical poles so that everybody knows
just where they are, but unless the mag
netic meridlans are precisely located the
geographical meridians are wen nigh use
less for exact calculations So great is
the effect of the magnetic meridians upon
the compass that ship may appear to be
going in one direction, according 10 the
geographical meridians whereas it is real
~ turning in another. Navigators are
Obliged TO make allowances for these
changes, in their calculations, for If they
did not they would be in imminent dam
ser at all times of steering into rocks and
reefs. and there would be no safety in
ship. Surveyors have also to depend upon
the magnetic meridians for their lines. ana
as the meridians change surveyors lines
would follow them and surveys would all
become tangled If allowance was not made
for the shiftings.
\ Vast Undertaking.
To catch the elusive magnetic meridians
and fix them so that surveyors and navi-
gators may know their precise location,
and make their calcula tions accurately, is
The work upon which the officials and the
Geodeuc and coast survey have embarked
in common with similar officials in almost
every government of importance in the
world, ana the entire earth will practically
be surveyed before it is completed.
The officials at Washington have been
for several years preparing for this work
Under the supervision of Charles A
SchotL assistant superintendent of the
survey, the most delicate instruments have
been made 10 register the lightest and
slightest magnetic impressions on land and
sea. and these Instruments have been plac-
Cd on board of every vessel of the coast
survey ana in nearly 200 observatories on
land
The difference between the magnetic
meridians and the geographical meridans
is like that between the magnetic poles
and the geographical poles. Only a mag
netic needle can follow their convoMtons.
A magnetic chart locks like a picture of
snakes squirming over the globe, their
heads conVerging toward a common center
ar the magnetic pole. The magnetic po,es
are supposed to be four in number two
in the northern and two IN the southern
hemispheres, ana they slowly shift their
positions around the geographical poles,
the periods of their changes being centu-
res. The stronger magnetic pole in the
entity of the mining region at the head OF
The great lakes and the weaker in Asia.
TO illustrate the manner in which these
poles shift their positions and thus change
the location of the magnetic meridians. In
1868 the magnetic pole was to the north
and east of Paris il moved westward until
1914 when il attained its western maximum
of - degrees "a minutes. In 1880 it was at
So degrees, AZ minutes west of Greenwich.
In 1865 il viii pass near the meridian west
of Paris and then il viii pass easterly I'M
I'll the year PIG, when il will be 80 degrees
east of Paris. The eastern variation at
Paris viii decrease, becoming zero in 2267
when the magnetic pole will return TO the
meridian Of Paris.
Columbus Found the AgOnic Line.
The line Of no variation. technically
known as the asouic line, is the basis of
an magnetic calculations, ana as it shifts
from place to place. allowance has to be
made for il in charts and by navgators
und surveyors. This is the line ON which
The needle remains true TO the magnetic
pole 1t was discovered by Christopher
Columbus during his first voyage of dis
covcry in 1892 in the Azores. Upon his re-
turn to Spain he announced it, but was
discredIted and IL was not until 1856 when
he had been long dead, that another navi-
gator Martin Cortez, corroborated him and
ne was believed. Since then it has made
some eccentric moves. In 1860 it ran
through New York city; in l770 it started
from a point near Birmingham. Ala, ana
ran due east across the Atlantic; in 1900
it had shifted so that il started from a
point near White river. Ontario, and ran
IN "A southeast direction past Georgian bay
through the peninsula. crossed Lake Erie
near Buffalo, ran through New York and
Pennsylvania, past Harrisburg, through
Baltimore, down the Chesapeake bay, to
Norfolk, along the coast to Hatteras, and
50 out to sea.
The line now runs from Lansing. Mich,
through Columbus. o.. Charleston, W.
" f1rDgph Arfrofpft tho Csaroftr,e raa.