Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1898-05-23

mate the tlattening Of the earth. indie
pendent of the measurement of the
arcs.
THE most important piece Of work
bearing on the determination Of the
figure of the earth that America has
contributed to the general knowledge
is probably the oblique arc which We
have measured from Maine to Mobile.
lis line cuts down along the AppaIach-
ian region aud runs from the north
eastern corner Of Maine To Mobile.
Another Is the transcontinental are
which starts at Cape May and goes on
the thirty ninth parallel to san Fran
cisco, which IL something rather unique
in that the longest line ever observed
In both directions il found thereon.
That line Is 1873 miles long. extending
from Mi. Ellen, having an elevation Of
i 600 feet 10 tucompaha2re, which ~
about II 600 feet high. The accuracy
THAI is attained in this work il remark
able There are inevitable dlEcrepau-
cies In Inc measurement; If angles. and
II il supposed that you cannot preserve
the accuracy ~ the base line forever
but TN this obiique are. they measured
a base line at Kent Isle. Md. ami an
other at Atlanta, Ga. and they carried
cut this tr!anguati1n If each base
to~ard the other. and mat somewhere
IN North Carolina Ia compare the
meeting lines They could calculate
on either base, and The result was that
the lines. about thirty miles long. show
ed q discrepancy between The two
measures ot not more than half an
inch. The TWO sets of observers war
each SO anxious u get out the results
first that as soon IS calculated they
mailed the length or rather the
logarithm, and the TWO letters cross ID
each other on the road, which show
that there was no fixing up the figures
in reaching this remarkable result.
The international Geodetic Asso-
citation is studying the effect of re-
fraction and alteration. the variation
OF latitude ami other kindred subjects.
Al The next meeting In October thay
will take III the variation IF latitude
and the idea is ~ determine this by
having four international stations all
on the same parallel at latitude, which
is going 10 be So and S. little north
Of Washington. near Rockville, Nd.
Two Of these stations will be in the
United States. one in the East and ona
in the West, one in Japan and one in
Sicily. The coast survey viii have
charge Of the two in the United States
AL the observations VIII be reduced in
Europe under the direction Of a central
bureau. When the coast survey stud
led these problems before. III conjunc-
ton with the Germans. each Govern
ment sent a man TO Honolulu. and
another man from each was stationed
at Berlin. They observed every night
when they could get stars for TWO
years and the TWO men at Honolulu
and the two men at Berlin brought
back results 50 opposite in character
as 10 fully establish the fact that
there was a slight Migratory motion Of
the pole, independent Of The regular
movements of the earth. Its period is
i27 days. II has been known since 1SSS
but We can go back to observations
made forty years ago and see the effect
Of the same fact Nobody was then
bold enough 10 say that the latitude
changes, for that is what she moVn-
ment of the pole means. Mr.. $. G.
Chandler Of Boston. editor Of the AS
Economical Journal. is the best author
ity in this country on the polar motion
He made observations with an instru-
ment floating in mercury, 50 as toI
avoid having to make the correction
for level, and made some very accu-
rate observations. After he had reg
istered them. he seemed to think there
was evidence that the latitude chang
ed, since that was the only way lel
could explain certain discrepancies in
his results, but he did not make the
assertion absolutely. The Germans
examined the matter very closely, and
from continued observations for two
years announced in about 1883 that the
latitude changed This. which Was att
first received With incredulity, is now
admitted on all sides.
In the same way the tetrahedral
theory is going through a period Of
probation. | am not prepared to say
that | accept it, and. if proved. the
amount of modification Of the spher-
oidal form of the earth in that direc-
ton will be very slight. of course.
But we know that the equator is not a
perfect circle, rather an elipse, and
the tetrahedray theory accounts for
some things not otherwise easily eN-
planned. Measurements on the fifty
second parallel in Europe showed that
that arc had radius of over 400 me-
tres less than in the Clarke figure, ana
then they measured another arc on
the same parallel, with a like result.
The evidence was unmistakabe as far
as it went. This arc in America seems
to show the same thing. The shrink
ing of the earth is a geological ques-
ton rather than a geodetc. but l be-
lieve it is scientifically admitted that
such process is going on. But our
coast survey service is primarily for
the making of maps. and it is one Of
cur first duties to determine the size
and shape of the earth, upon which all
else depends, and hence the greater and
painstaking experiments which the
Government is conducting in conjunc-
ton with the other Governments OF
the world"
LINCOLN