i47

ft,

Astronomy.

ftis his Light and Heat greatest, anda Pparent Diameter largest; and in this

Point

at C

P>m * n fame Plane with the Triangle A S B.Yrig n , ’ a nd because of the Parallels SB, C c, thethe! ? ^ C will be equal to the Triangle SBc,W etor e equal to the'Triangle SAB. By thehccefl- a y of Reasoning-, if the centripetal Force act*4 e"' 1 } 1 j" the Point " " ” .. ” ’ '

., U, earning me £>oay inme to describe the Right Lines

i - h P, bc. the Trianglesc ‘ will be equal, and all in the fame Plane

SCD, SDE,

t so. i n ; . , _

P r *bed , Equal Times, therefore, equal Areas are de-pths s/r? Composition of Ratios, any Sums ofY ^bicjj SAFS, are to each other as the Tin esi ^gles'h^- 3re ^ ei b cr ibed. Let now the Number-of6 * ncr eased, and their Breadth be diminished^ a p’ then will their Perimeter ADF be ulti-y 'Hi c j 1 ^ rv e : And therefore the centripetal Force,f I 1 of ®°dy is drawn perpetually from the Tan-o? 1 '^ a 1S Oorve, acts incessantly ; and the Areas de-f ^Heif-p. 6 i*'f° in this Cafe proportional to the Timespit. ^ ascription.

1 3tlet is siCe Velocity of the revolving Body orj 6t fall f r ever y where inversely as the Perpendicularh P] 0ftl Centre S to the Tangent of the OrbitA V S °f the Planet.- For the Velocities in thetiT> Bo bc. are as the Bases of the Triangles

the C c d. - -

; and the Bases of equal Triangles areSsinn -Y as their perpendicular Altitudes; andithere-'n the evanescent Triangles A S B, A f>C, or.% o.P n Lines A r, B A C e, &c. become Tangents tothe Points A, B, C, tf f. ’tis manifest thek Mi c ,i m those Points will be inversely as a fer-from S let ^1 upon those Tangent Lines

Val l^ e ! lce also it follows, that the Times in whichtches are described in any Planetary Orbit areL a directl y

£Fc. as being the Spaces described in