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abstractedly without rcspect to any Hypothesis, I can as easily conceive, that-the several Parts os a fhining Body may emit Rays of different Colours andöther Qualities, of all which Light is constituted, as that the. feveral parts of afalse or unevcn String, or of unevenly agitated Water in a Brook or Cata-ract, or the several Pipes of an Organ infpired all at once, or all the varietyoffounding Bodies in the World together, fhould produce Sounds of severa! .Tones, and Propagate thcm thro’ the Air confusedly intermixt. And if thcrewerc any Natural Bodies that could reflect Sounds of one Tone, and stifle ortranltnit those of another ; thcn, as the Eclio of a confused Aggregateof all Toneswould be that particular Tone, which the Echoing Body is dilposed to Re-flect ; so, since (even by the Animadversor’s Conceiiions) there are Bodies aptto Reflect Rays of one Golour, and stifle or transmit those of another ; I canas easily conceive, that those Bodies, when illuminated by a Mixture of all Go-lours, must appear of that Golour only which they Reflect.

But when the Objector would insinuate a ditsiculty- in thcse things, bysdluding to Sounds in the String of a Musical Instrument before Perculsion, orin the Air of an Organ-Bellows before its arrival at the Pipes ; I must confeß,..1 understand it as little, as if one had fpoken of Light in a piece of Wood *before it be set on Ehe, or in the Oyl of a Lamp before it aseend up thematch to feed the Flame.

You see therefore how much it is besides the Business in band, to disputeabout Hypotheses. For which reason I Ihall now, in the last place, proceedto Abstract the difficulties irt the Animadversor’s Diseourse, and without havingregard to any Hypothesis, consider them in general Terms, And they maybe reduced to these three Queries.

I. PVbether the unequal ftcfraclions mndc xcithout respcFl to any incquality ofbici-eknce, he caufcd by the different Rpfrangibility of feveral fftys ; or hy the Jplit-ting, hreakjtig, or diffipating the fame I{ay into diverging Parts ?

1. Whether there he more thun rtvo forts of Colours ?

3. yVucthcr Whitenefs he a Mixture of-all Colours?

The firft of these Queries you may find determined above by an Experi-ment, the design of which was to shew, That the length of the ColouredImage proceeded not from any Unevenneß in the Glaß, or any other Con-tingent Irregularity in the Refractions. Amonest other Irregularitics, I knownot, what is- more obvious to sospecsi than a fortuitous dilating and spreadingof Light after some such mannet, as des Cartes hath described in his ALthcreal\cfrailions for cxplicating the Tail of a Comet; or as the -Animadversor nowlüpposes'to be effected by the splitting and rarefying of his iEthcreal Pulses. Andto prevent the fulpicion of any seich Irregularitics, I told you, that I Re-fracted the Light contrary ways, with two Prifms succeffively, to destroythereby the Regulär Effects of tbe'first Prisin by the second, and to discoverthe Irregulär Effects by Augmenting them with iterated Refractions. Now,amongst other Irregularitics, if the hrst Prisin had fpread and’ diflipated everyRay into an-indefinite Number of Diverging Parts, the second fhould in like-

manner