The elements of astronomy, physical and geometrical (1715)
Gregory, David, 1659-1708, Halley, Edmond, 1656-1742. Synopsis of the astronomy of comets, Adams, John, 1735-1826, former owner. BRL, Boston Public Library (John Adams Library) BRL · London : Printed for J. Nicholson ... and sold by J. Morphew ... · leaf 509
n C and theTangent D R in D, and from P draw another lineP Nparaliel to it: And C D will Be equal to thelight line S L (by Frop. i;9. ^,4. of Gregory 5^-Vmant) and P N to P S. Blit G C is to CD ina given ratio, namely of G P to .P N; and there-fore EL is to LS in the given ratio of .G P to P Ncr G… … BookIIL e?/ A S T RO N O M Y* 43 I with ^. And fhis is evident from henee, that(by Trop, 34. 5.1, ff Conies.) RG being a Tangent^ .^5 is to SP as AG to GP; from whence, by.:permutation and inverfion, GJ is to AS asjGP •to P S, This Propofition holds alfo in the otherSedions of the Cone. Proposition…
Astronomy
Internet Archive · Boston Public Library · Public Domain Mark 1.0. Free to use for anything.
