( '6i )

4. Whitenesi, in all relpects like that of the Sun’s Immediate Light andof all the usoal Objects of our Senfes, cannot be Compounded of two Sim-ple Colours alone. For such a Composition mustbe made by Rays that ha veonly two degrees of Refrangibility, by Des. 1, and ? ; and therefore it cannotbe like that of the Sun’s Light, by Pros. 1 \ Nor, for the fame Reason, likethat of ordinary White Objects.

y. Whitenefs, in all relpects like that of the Sun’s Immediate Light, cannotbe Compounded of Simple Colours, witkout an indefinite variety of them.For to such a Composition there are requisite Rays endued with ali the in-definite degrees of Refrangibility, by Pros. 1 . And thole infer as many simpleColours, by Des. 1, and z. and Pros. 2, and z.

To malte these a little plainer , I have added also the Propositioris thatfollow.

6. The «Rays of Light do not act on one another in pafling thro’ the simeMedium. This appears by several former Paflages, and is capable of furtherProof.

7. The Rays of Light suffer not any change of their Qualities from Re-fraction.

8. Nor aftcrwards from the adjacent quiet Medium. These two Propositi-oris are manifest de facto in Homogeneal Light, whose Colour and Refrangi-bility is not at all changeable either by Refraction orby the Contermination ofaquiet Medium. And as for Heterogeneal Light, it is butan Aggregate of se-veral sorts of Homogeneal Light, no one fort of which suffers any more Al-teration than if it were alone, because the Rays act not on one another, byProp. 6 . And therefore the Aggregate can soffer none. These two Proposi-tioris also might be further proved apart by Experiments, too long to be heredeseribed.

9. There can no Homogeneal Colours be educed out of Light by Refra-ction, which were notcommixt in it before; because by Prop. 7, and 8, Re-fraction changeth not the Qualities of the Rays, but only separates tholewhich have diverse qualities, by means of the different Refrangibility.

1 o. The Sun’s Light is an Aggregate of an Indefinite variety of Homoge-neal Colours; by Prop. 1, 5, and 9. And hence it is, that I call Homoge-neal Colours also Primitive or Original.

VII. 1. I doubt not of what Mr. Newton affirms; and have my sclf sometimes irtlike Circumstances observed the like Difterence between the Length and Breadthof the Coloured Spectrum ; but never found it fb when the Sky was Ciear and freefrom Clouds, near the Sun: but then only appeared this Difference of Length andBreadth, when the Sun either Ihined thro’ a White Cloud,orenlightned some sochClouds near unto it. And then indeed it was no marvel, the find Spectrum fhouldbe Longer than Broad; since the Cloud or Clouds, so Enlightsted, were inorder to those Colours like to a great Sun, making a far greater Angle ofIntersection in the Hole, than the true Rays of the Sun do make; andtherefore are able to enlighten the whole Length of the Prifm, and not only-'some Imall part thereof, as we see enlightned by the truc Sun-beams comingVol. L Y tlnV

lAnimtiverfionson this Theory ofLight <tn.i O-lour; ■ by Mr. Fr«Linus, n. i io.p.217'