The Caldwell tribune. [volume] (Caldwell, Idaho Territory [Idaho]) 1883-1928, 1897-05-01
THE EARTH'S CURVATURE
THIRTY YEARS HAVE BEEN CON
sUMED IN THE MEASUREMENT.
The Most Gigantic Feat of Geodetin
Surveying Ever Accomplished
Anywhere in the World.

An arc 5000 miles in length. which has
been in process Of measurement by tri-
angulatioa for period Of over 20 wears.
showing the curvature of the earth's sur
face on this hemisphere. was conpleted
by the United States Coast and Geodetic
Survey early this month"; Although 1t Is
the most gigantic feat of geodetic sur
Yeylng ever accomplished anywhere in the
world, no public announcement of its
completion has heretofore been made, says
the Denver Republican.
Ihe enterprise was inaugurated by
president Jefferson in 1907, but no active
progress in pushing 1t was recorded for
many years later. Since 1874 several par
ties OF civil engineers have been at work
almost steadily between the Atlantic and
racine coasts making the triangulations
for the big arc, under the direct super
vision of the different coast and geodetic
survey superintendent. These earth meas
ures worked in general line toward one
another from both sides of the continent
About the middle of the month the two
base line from which the closing calcula-
tons have been made were verified One
was drawn In the state of Kansas and
the other in Salt Lake Valley, Utah.
Engineer P. A. Welker. who co-operated
with Engineer William Einbeck on the
Salt Lake valley base line, is now at the
Brown Palace hotel He has just return
ed from Utah, and is on his way to Wash
ington to report on his labors. The final
measurements in Kansas were taken I'M
der the direction of Engineer Granger
1T is extremely difficult to give in an
interview anything like comprehensive
and Ineligible account of the work the
United States Coast and Geodetic Survey
has just completed in this section of the.
United States" explained Engineer We'll
ker yesterday. 1.-THE general purpose in
measuring an arc across the American
continent Is, primarily, to get the true
curvature of the earth on this hemisphere.
An accurate survey, something that was
never before reached, is also desired. Sur
veys are generally made on the basis that
the surface of the earth Is fiat.
This country is cooperating with all
the other civilized countries for the COM
mon purpose of getting a new figure of
the earth established. This figure will be
an approximately true one, and is to SUI
persede the figure now in general use.
BessePs ellipsoid, the first figure of the
earth used by scientists, was established
from data collected by the Germans The
next elllpsoid--the one now accepted-was
established, think. by Clark, an Eng
lishman.
I'm 1874 an international agreement
was reached among the civilized nations
to take measurements for another ellip-
sold, one that win be practically true.
Every government of consequence In the
world has since been engaged In measure
ing out an arc on the surface of the globe
The arc in this country is the longest
measured by any one nation. 1t is 5000
miles in length.
From Atlantic to Pacific.
"All surveys in this country are to be
corrected by the arc measured out from
the Atlantic to the Pacific. The ordi-
nary surveys are inaccurate, as the sur
veying engineers do not allow for the
curvature of the earth. In surveying a
state, say they measure from county TO
county allowing for a fiat surface, and
the consequence is that the surveys thus
made overlap each other
''There have been a large number of en-
gineering parties employed on the Amer
lean and from time to time William Elm
beck, whom l Joined in Salt Lake Valley
last summer, has recently had general
charge on the triangulatlon operations
from the Pacific coast to the Rocky
mountains. Engineer Granger finished
up the work on the Kansas base line.
1.-TWO years ago the connection between
the eastern and western parties of en-
gineers were made at Mount Ebert and
Ouray. I was up there then, using the
Photograph in getting the measurements
among the mountains. By this system of
sun flaming much better work can be
done In mountainous country than on
the plains, as we get longer lines.
"a longer arc than ours is the one meas
ured conformity by England, Germany and
Russia. These countries combined on one
arc, and France and Spain on another.
The English have also done a good deal of
triangulation measuring in India. AS l
said before, all the important nations have
been engaged in the work.
at will probably be a year before the
calculations are all completed and a true
figure of the earth established. The arc
in this country will be combined with all
the others established over the globe, and
the mean curvature of the earth's surface
thus obtained. 1t Is expected that the tri-
angulation calculations, combined with
the use of the pendulum, will give us the
length Of the earth's diameter, to a de-
gree Of accuracy within a possible diff
ference of so feet from the exact
diameter"