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

O ITAPTIt: I, IV.
oP TIl',: SYSTE'M': o O'' IlE WORLD,).
4,309. I t'te airran.ygement f a ll the bodies that compose Iite tmateoirl n~ivterse,: and' thieir' Welatiodns to eac'h other, constitutes the
iS//stem, of the jjold, -(
It is otherwise called the Meelanism dof tfhle If[ea'vens; and,
ilndeed, in the System of the World, we figutre to ourselves a
nalchile, all the parts of which lhave a mn utulal dependencice, and
conispire to one great end. " Il aclines - that are first ilvcnted (says Adam Smitlh) to perform ilany particulalr moovemelntt are always the most complcex; and sulccecding artists
generally discoverl that Nwith fewer whleels (and wvith fewer plinciples of motion than hlad originally b)een employed, the same
cffects maylte more easily produced.'lite first systems; in thIe
samlle manner, are always the most complex; and a patrticular
colmecting chain or principle is gcnerally tthought necessary to
ullite cvcy two seemingly disjointed appearanecs; but it often
]ihppl)tnlS that one great co ninectingy rin e jyple is afterward.d found
to be stufficient to bintd togcether all the discordlant phllcnomelna
that occur in a wholc:species of thlings." This rem1 ark'is
st.rikingly applicable to thie origin and proegress: of systems of
astronomy.
440. From the visionary notions which are generally miderstood to have been Cntertained onl thlis subject by tlhe ancients,
we are apt to imnagine that they knew l1 ss ithan thcy actually
did of the truths of astronomy. But ]ytlhagoras,: who livedI
500 years bel)fore the Christian era, was acquaintc d with many
importalnt facts:in our science, and entertained nteta mally opinions
respectillng thle System of the World wlihell are lnow hel(l to be
true. AmonI g other thilngs well known to P'ythagoras wereo
the followino'g:
1.''l't lTc principal constellations.'These hlad? beguni to b)e
formed in the carliest ages of the mworld. Sevcral. of tihl3m
bc-ring' the sme llames as at present are mentioned iln the
writings of I csiod and Homer; -and theG sweet inlitielnces of