■to

Astronomy#

their Distances in the System above‘gn’d; But in the Ptolemean System, they

might

Q^y°- ’ s ca( V to observe, that since the same1S described in Times very unequal, viz. inits o?. tbe Planet describes the very unequal Parts^ti 0 ,j rblts ROZandZMR, the Velocity of thelfl th e 1 10 tbe former Cafe must be much less than that; that is, the Planet when direct moves ap-j _ lriu ch flower than when it is retrograde.

. . ...... „„ . ...

, lt . > e m also. Let S be the Sun, ACH the Earth’s

*t\ f lMK ■ ■ - — -

r •»w yi vr tiicvii vr irvri , v ij , v£ » *»*■'*

le RipeJ-' ' Ve consider the Dispositions of the Orbits ofof ' 0r Planets, we shall observe the same Phæno-». e m also. Let S be the Sun, ACH the Earth’sthat of Mars , and O L Q_the Firma-^ 0 M - ars - Through Mars at M draw Q_M Gr to touch the Earth’s Orbit in G and C,Cau se the Earth and Mars do both move thej*, the pj| ,> but the Earth very quick in respect of Mars ,f t Q , * n °rnena will be the very same if we supposeC|<: rtc e , e at rest, and the Earth to move with the Dif-i > their Velocities.

s e £in then be at Rest in M, and the Earth

i n -f hdotion from G. At G the Planet will be

i Rank .^ne O O, among the Stars at Q. Whenrt h TT - 1 ?I . t tr D

^rth : ' ^ xj» —1> — - ~

ig t k at H, Mars will be seen in the Line H p.C, btars at P. In the same manner at A, B,0. e Planet will be projected to the Points L,

lor '"S in L wm t

; Q Cr lbe s y. Heavens. Therefore while the Earthptov e ", P as t of its Orbit G A C, Mars will appeary‘ c h h e - r ° u gh the Arch of the Heavens Q_L O $ji^r of 1 *? from West to East is according to thetbe Signs, and the Planet will be direct in

^ a p.pe 3S Earth proceeds from C to D, Mars7 s on t > ar to move from O to N j and as the Eartham* b y L r °pR b p' F, to G, Mars will appear to re-a» 6 ^ r ch \ f ° Qj an d so measure back again they| e horn Q S “ e f°re : And thus during the Earth’s Pas-ic h ther e f t0 O, this Planet will appear retrograde ;°te must always be the Cafe when he is in3 Opposition

,*39

PlateLVI.Fig. 2.