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Tinged with Blue, Yellow, or any variety os other Colours, then is thatGreen Compounded of fi ich Colours, as at its edges Emerge out of it: Butif it appcar distinct, and well defined, and intirely Green to the very edges,without any other Colours Emerging, it is of an Original and Uncompound-ed Green. In Jike mannet, is a Resracted Beam of Light being cast oi? aWhite Wall exhibit a Green Colour, to know whether that bc Compound-ed, Refract tlie Beam with an interposed Prism, and if you find any Diffor-mity in the Refractions, and tlie Green bc transformed into Blue, Yellow, orany variety of other Colours, you may conclude that it was Compounded ofthole that Emerge : But if the Refractions be Uniform, and the Green persistwithout any change of Colour, tlien is it Original and Uncompounded. Andthe Reason why i call it <b is, becaule a Green indued with such pro-perties cannot be produced by any mixing of other Colours.

Now, If two Green Objects may to the naked Eye appcar of the sinjeCo-lour, and yet one of them thro’ a Prism leem confuled and variegated with'other Colours at the edges, and the other diffindi and entircly Green ; oristhere may be two Beams of Light, which falling on a White Wall, do to thenaked Eye exhibit die fame Green Colour, and yet one of them, when transmitted tino' a Prism, be uniformly and regularly Rcfracted, and retain itsColour Unchanged, and the other be irregularly Rcfracted, and made to di-varicate into a mukitudc of other Colours: I fiippolc thefe two Greens will in 5both Cales be granted of a different Origin and Constitution. And if bynaixing Colours, a Green cannot be Compounded with the Properties of theUnchangeable Green, I think I may call that an Uncompounded Colour, elpe-ciaily since its Rays are alike Refrangible, and Uniform in allprelpects.

The sime Rule is to be obferved in Examtning, whether Red, Orange,Yellow, Blue, or any other Colour be Compounded or not. And, by theway, since ali White Objects thro' the Prüfn appcar confuled and terminatedwith Colours, Whitenels muff, according to this diffinction, be ever Com-pounded ; and that the raost of all Colours, becaule it is the mofl confuledand changed by Refractions.

There remains now the t hirci Querie to be confide red, which is, WhetherWhitenels be an Uniform Colour, or a Drlhmilar Mixture of all Colours ?The Experiment which I brought to decide' it, the Animadversor thinks maybe otherwise explained, and lo concludes nothing. But he might easily have■sitisfied himlelf by trying,what would be rhe reluit of a Mixture of all Colours.And that very Experiment might have latisfied him, if 1 e hnd plealed to ex-amine it by the various Circumstances. One Circumftance 1 there declared,of which 1 see no Notice taken-; and it is, That if any Colour at the Lensbe intercepted, the Whitenels will be changed into the other Colours: If »11tfie Colours but Red be intercepted, that Red »Ione in the Concourle or•crolhng of the Rays, will not confftitute Whitenels, but continues as much•Red as before • and so of the other Colours: So that the businels is not onlyto Ihew how Rays, which before the Concourle .exhibit Colours, dp in theConcoucle exhibit White; -but to fhew, how, in the sime place, where the le-«yal sorts of Rays apart exhibit lever ad Colours, a Confusion of altogether

make