An introduction to astronomy: designed as a text-book for the use of students in college. By Denison Olmsted ...

ZODlIACAL, LIR,10T. 77
orlbit of the earth..it is brighter in the parts nearer thle sutt
than in those that are more remote, and terminates in an obtwuse apex, its light fading away by ilnsensible gradatiolts, until
it becomtes too feeble for distinct vision. Jlelnce its limits are', at
lthe same time, fixed at different, distances firom the stll by diffle-relt; observers, accordling to tleir resp)ectivoe powers of vision.
2. fis eulpels val 7/very m/ci twit qi/f t t't fle /Jrea,,t scuso),S /'/lthe
y/ca. Aboullt the first of October, in our1 climate (:iat. 4:l
i8'), it becol-ns visible before tthe dawn of day, rising alotong
north of tlle ecliptic, a.nd t.erlilnatinlz above the nebula. of
(llancer. A.bout thell middle of Novembe'r, its vertex is ill the
collstellation Leo. At thlis time no tralces of it are seent in the
Nwest after Suitset, but about the first of Dl)ecemlber it b)ecolnes
fiintbly visible in the west, crossingl te NMilky Wfay near thle
h orizn, and ea cling firom tile stlun to thle head of (apri-.orlolnn5s, fotilling, as its britglhtness increases, a counterplart1 to
the Mi\[ilky'Wary, between which on the rigoht, and tlhe Zodiacal
I, lit, oil tthe left, lies a triangul ar space emlnbracing the D)olplint. 1T roull the month of Decetmber, tihe Zodiacd1.I-ight is
seenl on both sides of the sun, namely, beftore the ml0ornXigt
an:tld aftert e t the eveilg twilight, sometimtes extending 50 westard, anll 70) east\ward of the stun att the same time. After it
blegins to appearl in the vwest-,ern sky, it in',reases ra1pidly
from nlgllt to night, b)othl in lengtl and brightness, and wvith.draws i;tself fr lom thle Iolling sky, wherel it is scar seen
after the montht of I)ecember, until t}he next October.
3. fhe Zod iacal it(gf lt ia)tvCS th?-outylt t(e ectavt s ite t/he
ord'.rr: /f the.sipwns. It moves Nwith unequal velocity, 1being
somnetitces stationary and sometines retrograde, while at otlher
times it advances mucll ftaster than the sun. Inl Felbrulary alnd
MINarc l, it is very colnspicunous iln the west, reaching to tlte
Pleiades anid beyondt but inl A.pril it becomeis mntoroe fai;tt, and
nearly or quite disapp)ears dluring the month of M[ay. It is
scarcely seen ill this lattitudle durig the summer molnths.
4..1 It, i-Mtt?.arkably eons2tie:ew.to, at certain.perioc tv q/t ag/w
ea?.cti, atR thee faor a long/ intetrval tlhmoslt ist ppears.
5. ['he Zodiaca it/l. twas formelty heed to be t ie an. t. osp2iere o tIhe, stn.' But ]La P.lace lhas shown that the solar
* M5hsran},;J1Memonlvnrirs lFrenclh Acadenmy, for 1733.