Produced 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
to their Secretary, and read at their Meetings, and the rest was added
about twelve Years after to complete the Theory; except the third Book,
and the last Proposition of the Second, which were since put together
out of scatter'd Papers. To avoid being engaged in Disputes about these
Matters, I have hitherto delayed the printing, and should still have
delayed it, had not the Importunity of Friends prevailed upon me. If any
other Papers writ on this Subject are got out of my Hands they are
imperfect, and were perhaps written before I had tried all the
Experiments here set down, and fully satisfied my self about the Laws of
Refractions and Composition of Colours. I have here publish'd what I
think proper to come abroad, wishing that it may not be translated into
another Language without my Consent._
_The Crowns of Colours, which sometimes appear about the Sun and Moon, I
have endeavoured to give an Account of; but for want of sufficient
Observations leave that Matter to be farther examined. The Subject of
the Third Book I have also left imperfect, not having tried all the
Experiments which I intended when I was about these Matters, nor
repeated some of those which I did try, until I had satisfied my self
about all their Circumstances. To communicate what I have tried, and
leave the rest to others for farther Enquiry, is all my Design in
publishing these Papers._
_In a Letter written to Mr._ Leibnitz _in the year 1679, and published
by Dr._ Wallis, _I mention'd a Method by which I had found some general
Theorems about squaring Curvilinear Figures, or comparing them with the
Conic Sections, or other the simplest Figures with which they may be
compared. And some Years ago I lent out a Manuscript containing such
Theorems, and having since met with some Things copied out of it, I have
on this Occasion made it publick, prefixing to it an_ Introduction, _and
subjoining a_ Scholium _concerning that Method. And I have joined with
it another small Tract concerning the Curvilinear Figures of the Second
Kind, which was also written many Years ago, and made known to some
Friends, who have solicited the making it publick._
_I. N._
April 1, 1704.
Advertisement II
_In this Second Edition of these Opticks I have omitted the Mathematical
Tracts publish'd at the End of the former Edition, as not belonging to
the Subject. And at the End of the Third Book I have added some
Questions. And to shew that I do not take Gravity for an essential
Property of Bodies, I have added one Question concerning its Cause,
chusing to propose it by way of a Question, because I am not yet
satisfied about it for want of Experiments._
_I. N._
July 16, 1717.
Advertisement to this Fourth Edition
_This new Edition of Sir_ Isaac Newton's Opticks _is carefully printed
from the Third Edition, as it was corrected by the Author's own Hand,
and left before his Death with the Bookseller. Since Sir_ Isaac's
Lectiones Opticæ, _which he publickly read in the University of_
Cambridge _in the Years 1669, 1670, and 1671, are lately printed, it has
been thought proper to make at the bottom of the Pages several Citations
from thence, where may be found the Demonstrations, which the Author
omitted in these_ Opticks.
* * * * *
Transcriber's Note: There are several greek letters used in the
descriptions of the illustrations. They are signified by [Greek:
letter]. Square roots are noted by the letters sqrt before the equation.
* * * * *
THE FIRST BOOK OF OPTICKS
_PART I._
My Design in this Book is not to explain the Properties of Light by
Hypotheses, but to propose and prove them by Reason and Experiments: In
order to which I shall premise the following Definitions and Axioms.
_DEFINITIONS_
DEFIN. I.
_By the Rays of Light I understand its least Parts, and those as well
Successive in the same Lines, as Contemporary in several Lines._ For it
is manifest that Light consists of Parts, both Successive and
Contemporary; because in the same place you may stop that which comes
one moment, and let pass that which comes presently after; and in the
same time you may stop it in any one place, and let it pass in any
other. For that part of Light which is stopp'd cannot be the same with
that which is let pass. The least Light or part of Light, which may be
stopp'd alone without the rest of the Light, or propagated alone, or do
or suffer any thing alone, which the rest of the Light doth not or
suffers not, I call a Ray of Light.
DEFIN. II.
_Refrangibility of the Rays of Light, is their Disposition to be
refracted or turned out of their Way in passing out of one transparent
Body or Medium into another. And a greater or less Refrangibility of
Rays, is their Disposition to be turned more or less out of their Way in
like Incidences on the same Medium._ Mathematicians usually consider the
Rays of Light to be Lines reaching from the luminous Body to the Body
illuminated, and the refraction of those Rays to be the bending or
breaking of those lines in their passing out of one Medium into another.
And thus may Rays and Refractions be considered, if Light be propagated
in an instant. But by an Argument taken from the Æquations of the times
of the Eclipses of _Jupiter's Satellites_, it seems that Light is
propagated in time, spending in its passage from the Sun to us about
seven Minutes of time: And therefore I have chosen to define Rays and
Refractions in such general terms as may agree to Light in both cases.
DEFIN. III.
_Reflexibility of Rays, is their Disposition to be reflected or turned
back into the same Medium from any other Medium upon whose Surface they
fall. And Rays are more or less reflexible, which are turned back more
or less easily._ As if Light pass out of a Glass into Air, and by being
inclined more and more to the common Surface of the Glass and Air,
begins at length to be totally reflected by that Surface; those sorts of
Rays which at like Incidences are reflected most copiously, or by
inclining the Rays begin soonest to be totally reflected, are most
reflexible.
DEFIN. IV.
_The Angle of Incidence is that Angle, which the Line described by the
incident Ray contains with the Perpendicular to the reflecting or
refracting Surface at the Point of Incidence._
DEFIN. V.
_The Angle of Reflexion or Refraction, is the Angle which the line
described by the reflected or refracted Ray containeth with the
Perpendicular to the reflecting or refracting Surface at the Point of
Incidence._
DEFIN. VI.
_The Sines of Incidence, Reflexion, and Refraction, are the Sines of the
Angles of Incidence, Reflexion, and Refraction._
DEFIN. VII
_The Light whose Rays are all alike Refrangible, I call Simple,
Homogeneal and Similar; and that whose Rays are some more Refrangible
than others, I call Compound, Heterogeneal and Dissimilar._ The former
Light I call Homogeneal, not because I would affirm it so in all
respects, but because the Rays which agree in Refrangibility, agree at
least in all those their other Properties which I consider in the
following Discourse.
DEFIN. VIII.
_The Colours of Homogeneal Lights, I call Primary, Homogeneal and
Simple; and those of Heterogeneal Lights, Heterogeneal and Compound._
For these are always compounded of the co
评论1