St. Tammany farmer. [volume] (Covington, La.) 1874-current, 1894-09-08

GlRTH OF The GLOBE.

GlRTH OF The GLOBE.
Efforts Of the Scientists to Ascertain the
Exact Distances.
For thousand years men have been
trying to determine the exact distance
around the world. The distance was
long ago calculated approximately at
~ .OOO miles. but the time has passed
when scientists can be content with \
result expressed merely in round num-
bers of miles. Andrew Braid, execu-
tive of the coast and geodetic survey,
recently said that he believed the dis
tance would eventually be computed
so that the error in the diameter would
not exceed 20 feet.
The basis for this statement is to he
found in the fact that the United
States coast and gcodetic survey will
in few months take up this huge
problem for solution.
The task is one of great magnitude,
and will require from two to three
years of solid mathematical grind
ing" such as would turn the majority
of students pale.
The most recent authorities differ
much with each other. The two
Frederick w. Bessel, distinguished
German astronomer. and Col. A. X.
Clarke. an English engineer, are at =
variance with each other about the
diameter to the extent of one mile, and
during the last thirty years. since the
results of Col. Clarke were promul-
gated. the surveyors of different couu-
tries have been dicided against them
selves on this question.
The preparation for this mammoth
of the mathematical men
of the survey requires the actual
of the longest possible
ON the earth's surface. This
is what is technically called an arc, be-
cause it comprises portion OF the
earth's circumference. The surveyors
will soon have an arc of 5000 miles in
length. extending from the Atlantic
TO the Pacific ocean. which has been de-
lermined with precision by the use of
The most accurate instruments and the
of the most skilled men.
This line is along the thirty-ninth par
allel, and will be completed with the
system of triangulation through what
IS called the continental divide, the pres
ent season.
The principle for determining the
of the earth in this case
is easy of comprehension. The survey
DIS are able to determine the difference
in longitude of the two extremities of
This long line, which begins in New
Jersey. near the southern part of Cape
May. and ends in the lower part of
county. California. Know
ing that the whole circumference Of
the earth comprises 800 degrees
IF circle. and reckoning the
fractional part of this circle,
which is covered by the arc, the
gvhole distance is readily computed.
The difficulty comes in reducing the
taken from the series of
triangles extending across the conti-
nent to a sea level, for many of the
ines from which the distance must be
are situated on the mountain
ops and in many cases above the
clouds, especially in the mountainous
-cgions of the west. through which the
parallel passes. The measurement of
he earth's circumference is to be ac-
incidentally to the other
work for which the triangulation is
designed, and therefore the final re-
,ults will not be obtained for q consid-
.rable time.
In more primitive times men made
many attempts to ascertain the dimen-
ions of the globe. A Frcnchman
named Fernel. court physician to
Henry H.. in the early part of the six
eenth century. had an ingenious but
rude scheme for measuring with q
wagon wheel, which would have been
facilitated by the use of the modern
'yclometer. He travelled due north
rom Paris to Amiens, what he calcu-
ated to be a degree, and. sseturning
of his wagon wheel 20 the
number of l7.O24. Those amounted to
Is Italian miles and 96 PAGES, &C.
,ording to his computations, and in
this by 500 he believed
hat he had the approximate distance
lround the world. He was not far
rom the truth, but his rude methods
would come far short of satisfying the
demands of science in these
lines. He supposed that the earth was
ound. and took no account of the wab-
bling in and out of the road. or the in
curvature of the path of the
Wheel from q straight line.
The ancients, however, were fully rs
hrewd as Fernel, and more than 2,5OC
ears before his time they arrived at
he same results by methods equally
lever. The Chaldeans worked on
he problem and reckoned by camel
teps. They had it that 1000 camel
teps were necessary to make . mile,
md that 33H miles were one-half of
legree. From this they declared that
t was "a, 900 miles around the world.
In connection with their triangula-
ion, the surveyors are attempting to
earn what is the exact shape Of the con-
inent through which their labors ex-
end. This has a great deal to do with
correct computation of the distance
or through the earth. In fact,
hey know that the earth is far from
eing what they call Clarke's spheroid.
hat is the present scientific name for
he earth since the American surveyors
that Col. Clarke's dimensions
vere most nearly correct A large part
+ the north American continent bulges
ut abnorn,ally, like q rubber ball
shich is squeezed by q strong hand.
his is one of the things. that puzzles
he wise men. The great western
lateau is elevated above the leve
+ equilibrium probably more thar
., 900 feet on an average. The
heory is that the mass of the earth
viscOus, but this immense
lateau. weighing billions and billions
tons, is supported in some manner
the great height. when on geneul
IL should sink down to the
evel of the sea. On the contrary, the |
reat plateau is probably rising, and
lumb bobs and pendulums. which are |
tilted in reaching conclusions on