, 1879-08-09

showers which hAQc Geen fccofued al0We that
tic point whcEe the path Of lc ueteors crosses
tic c4rths orbit Is not xed, but that every timo
thu tuctcors come round they strike tho
carth'a orbit at po!nt which Is twenty
ntuc minutes q. c., nearly half Il degrce) farther
on in tl.e direction In which the earth Ia travel
iue. In other words, tic motcors do not de-
scrlbe rxActlY Tic sau,e orbit over and over
a4yatn tllcr path In one revolution ts not exact
" tllc same uB their path III the next revolution.
although very close to f.: Thus, their path 10
A. d. 12b was that which Ia represented by the
strt,ng oral line In Tho diagram, hut, In the aev-
cntton centuries which had since elapaes. II has
gradually shifted fo'iM IL fhs position sE topfo-
tim Is we'll known to astronomers, and It's Cause
is we'll known. II would not happen If the sun
wern the only body attracting the mctcors, but
otl'cr. directions; and although te attraction Of
the planets Il yeFy weak compared With tile lsa-
meuse power Of tho sun, still ttcY arc abe to
drag the mcscorB llttle ont Of thcir course
shifting ro,iud q the orbit Of which we
aro speaking. Now, In thu case OF ms
tcors v4et, arc really travelling III the lnsga
orbit, this shifting of the orbit must be due TO
Urau,ls, ntsl the Earth, while, Il They had trav-
cleh In any Of .hu four smaller orbits. t!o
planets thAt would bo near enough, H'!d large
dHough to act scnsi1!y upon them would oe tho
ono could DO found nblo to calculate how much
nlrcct would be produced IN each of the t1ve
cast-s, thu calculated amount Of shifting OF the
orbit could be compared with the observed
amount, which ls - 1nlu. In thlrtythreo n,lu u
quarter years. and this would at once tell which
OF Lie 1lyo possible orbits ia the true ono.
These papers Of Pfol; Ncwtons were pub
lisf.cd III 1874. Before tl.c computations which
necessary t.iut tho direction In wtifct, the me-
ieors enter the eaEtt's atmosphere should bc
known murt, tnoEo acclratci! shnn It then
was' in order to unable astronomers
lions Of tho tive posalblu orbts.' THIS obscr7a-
tion, then, WAS OF the greatest Importance In
1851, 1ltI II waa on this necount thnt aI the ns-
tronosuer6 Oil that occasiot, devoted nearly oil
lht!r efforts to determining With tic utmost
| precision the o1act point Of tile constellation
Leo, from which
| THE METEoRs SEEMED TO nAn1ATH,
Tll[s Important direction was aacertnnea durIng
tlIH great 1lcteosic shower OIL the morning of
| ihe 18th Of November. 1855, anl !mu,cuIntclY
after Prof. Adams mud Ills Two assistants in te
| CainbridVe Observatory fct to work at their
Ar.!.Ious task. This grcat calculation required
thu solution Of II problem In mechanics which,
fsad never brforc bce,l attempted, mid inyolvcI
Al, ttntne,sc nfnouslt Of tedious labor. Amid all
ta!cHu difficulties l'rot, Ada,ns trutnphed; and
after months Ut toll he was able to announce In
tie following. ,Mnrch that, u the 'netaors uro
moving III tho large orbit. Jupiter would prodcs
q shifting II thu orbit IN each revolution asnount-
| l,,g to 70 lnin.. tho attraction ot Saturn
would aud tu .h!a mln., Uranus would nah |
n,In,; tho effect q tho eattn u!M! o'her planets
wuulu be tnsen4tbie. As!'iIns tllrsc nunbera tn
gct.er, tic whole effect, according to Mt, Adams
computation. IL ~ nin., utmost cxnctlY tho snlna
rs The ot,suryeu Atnount wsi*ll had beun dotcr~
InInch by Prof. N9wtuII, which WIS 20 InIt,.
but, II The mctvora wera III my Of tlu o. her tour
possible urhts, tho tniat amount would nsytr
Gscccd IL 1nn llcEe, then, NO have rcnct,ed the
!lMAl result: Ihs hag orbit Il The orbit of the
sI*' saf5 ,}7 Th'' great discovery was published III
Meanwhile stgnor scllapparctlt, OF Milan, nas
lafl0rlg ~ au1:hcr direction. 1t WIS eyi1ent
from the observations that the .ncteors wurc
cause Of thtst StEnor asl.lannasc!l polntod out
that II a cloud OF 1netoors wcro startul under
conditions which aro not 1Nttu tbs same, each
nrteor you'd pursus IT. own orntt, which
treated almost exactly. though not quito, altkc
" starting. tl.eir yurlous nrb!ts would lie tx
cessiyely closo to ono another. md would bo
EndstinEutlhahla in most rrst,ects. Hut II
IRON revolution tu revolution. such an effect
would In the end BECOME very sensible. Aud
such I'LL effect there II.
TuE PEnloDIo TIMES pIrpER LlrrLH
In these different orbits. At the emf OF Tho first
revolution thusc insteors wh!ct haYc lha 1ongcs
periodic t!tnos aro tsle last To yet hack to tx
AtArt.lg polnt, anil llsye, therefore. alread1
fallen llttlu iuto the rear Of tic xruup, wli't
thuse wlth tho shortest periodic titnc have gon'
u little ailead. At tic end OF Tho sccoru Eevo
luton thu separation u doubled, aud IN eacl
successive revolution the column ta still uuri
!ensthened out. After sufficient number q
rcsuutions It will 10 sprcad nut over tho w|lols
lsuyth Of thu orblt, aud form . complete oya
ring. THIS has mt yet happened to shu Noyctn
bdr ncteurs. and wo aro thus assumed that j
cannot hu auY ENORMOUS period, speakl1ll
co,nlutGaly, since the tins when they rst starte.
Oil sl.uir prescnt patl. On The ollcr slntl. til.
August 1lcieors, which haYo returned pllucta'l1
eeerg year sineo tlcy were first observed, ar'
! uruGabiy II cumplc:c ring, and ars as oil rycnls
) OF ! far greater antiquity than tho Noyeubt
mcseocs. Hut they arc a'so. III might bu TX
pected, lnoru scattered, 10 that the sprfnklin}
Of 'nuscors they discharge Upon tho earth as I