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

T1E'TYCIrONIO SYS'TEMt. 311
146. Such a deferent and eplicycle may be devised for each
phlanet as ill fillly explain all its ordinary motions; but it is
inconsistent with tihe ptases of.ercury and'Venus, whichl
beilng bctteen us and the sun on both sides of the epicycle,
twould present thcir dalrk - sides toward ius in both these positions, iwhereas at one of the conjunctions they are scen to shine
with lfill face. I: is rmoreov1er absutrd to lspeak of a gomletrical center, whilelh lhas no bodily existencee, Imoving around th1e
earth on the circumference of another circle; and htencl somo
suppose that the ancients merely assumed this hypothesis as
afordillng a' conlVcnient geometrical representation of tlte 1phenomcnaa-::a- ( tditagram simply, without conceiving the system to
have aniy rcaln existnc)e in nature.
447. Thle objections to the Ptolemaie system, in general, are
the following: I.First, it is a mere hypotlhesis, havilng 1no evidence in its favor, except that it explains tle phenomena. t'llis
evidence is insuflllicient of itself; since it fiequently hapllens that
each of t\wo:hypotheses, directly opposite to eaet othler, will
explaiin all the 1known phenomena. Bu:t the?tolemlaic system
does not evien do this,l as it is inconsistent -with thie phases of
Mcercury and Venus, asalready observed. Secondly, now thlat
we -are acqluainted: ith tAhe distances of the remoter planets,
andl -eseecially of the fixed stars, the sw iftness of motion implied
inl a daily revolution of tlhestarry firmament around the cart h,
renders such a iotion wholly incredible. Thli'dly, the cetl'tf-?/al/tfJrce that would lbe generated in these bodies, especially
in tihe sunll, lrenders it' impossible thalt they canw continuoe to rcvolvo:aromnd the earth as a center.
T;hlcese reasonlls are sufficielnt to shoow the absurdities of tho
Ptolcmaic System of the World.
TIlE TVYif0lONOt 8YST3M.,
448. Tlyclho Bralh, like Ptolemy, placed the eartll in thl
center of theo univerlse, and accounted for the diurnal motions
iln thesame nanner as Ptollemy had done, namely, by an actiual
revolutioll of tile whl0ole 1host df heaven around the earth every
tw'llty-f)'ur o10lurs, u131t hlo rejected the scheme of deflrents'i...' Co..........t S,................
o VinCo's CoMPlCto System, i., p. 96.