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

RElrJATION5 }nlR'WEltRN B]ODI)lS OF rlitH SOL,AR SYSTE:'M]. 2-3
number of times exactly, while alloter plallcet, next to it, revolved a certain other even number of tilmes, then, whlblt thley
once came into the sphere of each othetr's influencc, tlheiy miglt,
remain undler it so long, and return to their rclative position
so otten, as seriously to derange their orbits. An instance of
this, in fact, occurs in the case of Jupliter and Satlurn, live revolutions of Jupliter being nmearly equal to two of Saturn, a relation whlich gives risc to whlat is called the long inequaltity (of
SatunZ. aQnd YJiiter. Similar effects result from a near commcnsurability of the Inean motions of any other two 1)lancts.
One exists bletween the Eartil and Venus, 1.3 times the period
of Velnus being very nearly equal to 8 times that of the Earthl
still tlhe ifltuencce of this disturbing cause is so nicely con)mpcnsatel, and its effects so distributed, thtat, according to MAr. Airy
(whio was tlhe first to (letcct it), it amounts, at its,maxi1muln, to
no more thlan a few seconds for a period of f240 years. Thlc
laws wllich regulate the eccentricities an(d inclinations of the
p)lallctary orbits (says an able writer on Pthysical Astronomy),
colllmbind with the invariability of tlhe meian distances, Ssecure
tihe permanence of the solar system throughout an inldefilnite
lapse of ages, and ofler to us an impll'ressive iltnlication of tlhe
Supreme Intelligen e wlhich presides over nature, and perpetinates 11ci' beneficent arran'it-eentts. When conteil)latc(l
merely as speculative trutlls, they are unquestionably tlle lmost
ilnlortant wvlichl the transcCendenltal ainalysis has disclosed to
the. researelhes of the gcomleter; and tllceir complete establishmenit would suffice to imllnmortalize the names of JLagrange and.Lalacc, even altllougll tllseo great geniuses possessed nlo othecr
claim to the recollection of postcrity.x
hNUMIERIOA I, RLtEInLIONS JI'i+W tEN T'HE Bf O1)XIES OF TIlE,
SOLAR SYTs'rEIU.t1
387. Iff we contemplate the relations subsisting between ac
central body, as the sun, anld a revolving body, as one of the
0 Glrant's list. Phys. Ast., p). 66.
- Int thte preparation of this article, tlhe aulthor ihats dCtived much "assistance
from a su.nal work, now nearly out of lprint, contaiting thle substance of threei
lecturcs duliverted to tihe Students of Yale College int 1781, by tecv. Nteheimialt
Strong', at that timet'rofe0sor of Mathematics and Natural Philosophy.