؀nProduced by Suzanne Lybarger, steve harris, Josephine Paolucci and the Online Distributed Proofreading Team at http://www.pgdp.net. OPTICKS: OR, A TREATISE OF THE _Reflections_, _Refractions_, _Inflections_ and _Colours_ OF LIGHT. _The_ FOURTH EDITION, _corrected_. By Sir _ISAAC NEWTON_, Knt. LONDON: Printed for WILLIAM INNYS at the West-End of St. _Paul's_. MDCCXXX. TITLE PAGE OF THE 1730 EDITION SIR ISAAC NEWTON'S ADVERTISEMENTS Advertisement I _Part of the ensuing Discourse about Light was written at the Desire of some Gentlemen of the_ Royal-Society, _in the Year 1675, and then sent to80ir Secretary,%A& u(ir Meetings the rest was added about twelve Years after to complete84Theory; except,third Book, Q lastA posiAM11dSecond, which were since pogether of scatter'd Papers. To avoid being engaged in Disputes a hese M@s, I haavi_ to delayeihpAqing),should still5 ,$it, had no (ImportunityFriends prevailed upon me. If any o}  writ on!=Ds Subject are got -my HaT they$ imperfect %@perhap R$ten beforepd tried all the Experiments h%|et down O,fully satisf7my self9S Laws of &EnCom.C$.!xlhpublish'd what I think propUhe abroaA!ish!t,it may%z$be translainto ano%Z0Language with!C\my Consent._ _The CrownQsometimAAppearSunMoon, I EK endeavourAF|o give an Account of; but for waH sufficient Observaa s le!$Iaube far examined.a} Q,of aTu}1m$also left ].Ahav%RbiI!V! en I'yW (s, nor repe%!Ba thoseLdiAy, untildFcaI8ir Circumstancei$communicat]AAA ied,! 1Ito Es%1NEnquiisp0my Design in M%'BmE?In a LeealHto Mr._ Leibnitz _iae yAC 1679Qed by D2(Wallis, _I a0ion'd a Metho:1sfound)ageneral emsMsquarCurvilin(Figures, or!?p " theme#  Conic +%5 sistJ 7 abe "arAAn Dgo I leaut@anuscript contain such)2Mmet {EdT!s copXofI VOccasiadeD%ck,fixztoan_ Int !,, _and subjo Ha_ Scholium _conceri%. 8aAith it smA Trac%FeNa5 Ki:aHA many9u)Dknown!< ͦo!de soliciMkmak!it1-A _I. 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