Telegram-herald., 1890-02-17
HoW THE 6ARTe MOVES
rrefessef searis Haias Al WAssal.stos q
AS >pheT4ix and Molten

. -NAta% Ar~AAt 81 " asttAEftff
AS SpheTiis @ad Motion.
lne sorond lecture ~ fhe publlo astrauorli-
~ oourse ey ProiesSoS GeorF. n Sssrls "A
tue estaoiic university on FRIDAY afteraooas
wss ga the sub5e-t ~ The spberlty ahS nsoti Ia
oi The earth. Tie iecturer sskea has hearsrs
g. imagine themselves "a tls decf ol AZ ,srean
steamer hound for the TROPICS AZ darknsss
comes cu we begin 70 sIady the snnsss afions
thai sonle fTselsd 81 our elbsow l. 'rs~dy g
Fsolnt oul to Is. hs SAD Ne uo14os so1lss
star tWlnsllng near TIE Aoriaos, Jnsi making
F rs dslg circle around ths uumovlng pois star
+ above. one ~ the seven stArs 81 the npper
F lei a. note carefully ale relAtaon u thAi stssr
Z q the horlson and to the ssers ~ the surround
. lug heavens Ne have os-y d tAks Out ear
watch and make note 81 tLe time. and go
. astronomical work NAV he lsia assoc for' The
evening Tomorrow night iet NJ olaBs out
on oeck al the same tiule aat look a. Ias slar
IA lis relation a. tae pole star and horizon a.
belore. Bat Tie Dpper that y ~ reslsrdaY 0n
the So hle has a-nosi disappeared itlcn TIE
iue. Last llghi ghe wake u tie slip was
P@uts4 toward Wonder star and now ~ ~ a
good oeal above it although our dlreciiau
has no. chauged We are stiH going sousA
but south nov Is not the same - soual then
have descended into the sea
Al last we reach the equator, aa5 we and
tie pole star Itself las sunk dow - the ho.
rl1on. We So no pole star in the south. tut.
as our studies on a lreyious occasion have led
Ne 10 expect, There j. a spot unmarked ty
any especially brilliant orb. around Nhioh
the stars II the southern heavens circis
There Is no explanation for this. except that
u -
over a curved one. II ve compare the ~.
tions OF ssy that appear in the south or dis
appear in the north with the number of mile
passed over by our ships log Ne shall find
that they have always been in proportion
We have then been sailing of steGmine over
great circular arc instead of 3 straight llne.
as K appesred - be
There are other proofs than these of the
circular character = fhe earth. the lecturer
said. We have only % look out T. saa when
"A ship Is leaving port IL Is now just on the
horizon. ana presently only The InaSis are
visible and the hni Is seemingly under wAier.
Something has intervened between tbs vessel
and theeye. What can this lie but tAs curved
surface Of the ooe&ni
A grander and more direct proof than spy.
II we could only realize r. is that which We
get III ecbp~es of the moon Before an sclip.~
becomes total watchers viii Zee q curved Inc
which marks the edFe 81 the shadow thrown
by the earth upon the lunar surfao<. and al
know that al object which slwars casas a
regularly and uniformly curved shadow n,u,t
be "A sphere
The first illustra tlon though not ~ striking
as some Others, is the best, for II shows net
only that the earth y round. bot Also lust
what the amount Of IL curvature is Hence
II is found out what rs siHe Is a. well a. is
shape. One days voyage ou the southward
bound steamer brings the star which vas
seen the night before Just appearing above
the southern horizon a good distance above
the waters edge How many sDch hfts
would be required 10 bring il up D. the zenith
right over our headsi Suppo-e ne thought
that iiftsen would be needed. II then We
could keep on for - days u would h< m the
zenith, in 80 days II would be th~re h~hipd
US IN - il would b. down baiow the hori-
zon, directly under our feet and ia a. davs
u would he in the same place again " here il
IS al present Ia other words. We would in
90 days have returned 10 Just where ". are
now. Our log tells us We have travsled 400
miles each day, and 90 tinlss tt1ns would n.
- 900 miles TINS, then, Is the circunnfsr-
ence of the giobs A"
There Is stall, the lecturer said. q more nc
curate method than that which he de~rrih.f
By making otEserv atoms with delicate instfal-
mentS upon the land instead % with the loo
which is 70 Inaccurate, u has ben possible 20
measure accurately the arc ~ the meridian.
and the true circuinference of the earth hns
thus been ascertained
The lecturer referred - the re-ulisrifias of
the earth shape and its fsttenIng n the re-
gi0n ~ the poles, snd then yrooo.ied o. give
tho scientific demonstration 81 the ia. that
tho apparent motion 81 the heavens is really
csusei by the motion ~ the earth itssH IL.
periments show din1inution in the weight
II objects as We approach the equator. which
shows That the equator u really in motion
portion q TINS dBniuuison. however. can
b. accounted for by the slight difference IN
the rofundity n tbe earth 81 The equstor and
toward The polr-, and r. infsr from ~ ~.
earth's motion it BE- necessary - asgrrr,s fbs
nearly uniform density ~ tho glot,e Wash
iueton Star.