the various circomftances^ Oae eircumftance F there decfa * 
redg of which I fee no notice taien; and it is^, That if any co* 
lotir at the L^«/ beintereepted, ihQWhitenefs will be changed 
into the other colours .• If all the colours but redbt intercept 
ted, that Red alone in the coucourfe or croffing of the Rays 
will not conftitute Whitene'fSj but continues as much Red as 
before; and foof theothcr colours. So that the bufinefs is 
not only to lliew, how rays^ which before theconcoarfe exhi- 
bit colouriS; do io the concourfe exhibit /F)^^/^ 5 but to iliew^ . 
How in the fame place^ where the feveral forts of r^ys apart 
exhibit (everalcoIourSjaGonfufioo ofall together make White. 
For inftancel, if red alone be firft tranfmitted to the paper at- 
the place of 'Concourfej and then the otiier colours be let fall ^ 
on that Red j the ^eftion will be. Whether they convert it in^ 
ti White, by mixing with it only, as Blew falling on Yiellow 
light is fuppos'd to compound Green 3 or^ Whether there be 
ii>me further change wrought in the colours by their mutual 1 
acting dfl one another^, until!, like contrary TeYtpatetic quali- 
ties, they become affiniilated. And he that (liall explicate this- 
laft Cafe mechanically^ mull conquer a double impolEbility, 
Me aluft/r^fliew, that many unlike motions in a Fluid can by 
clafliing fo afl: on one another, and change each otherj asto 
become one Uniform motion 5 and then^ that an Uniform mo- 
tion can of it felfj, without any new unequal impreffiooSj de- 
part into agreat variety of motions regularly un-equaL And 
after this he muft further tell mej Why all Objedts appear 
not of the fame colour, that is, why their colours in the AJr^ 
where the rays that convey them every way are confufedly 
mistj do not affimilate one another and become Uaiform be- 
fore they arrive at the Spedlators eye f 
But if there be yet any doubting/tis better to put the Event 
onfurther Circumftances of the Experment^ thm to acquiefce 
in the poffibility of any Hypothetical E%p\ication, Asj for in- 
ftance, by tryingjWhat will be theapparition of thefe colours 
in a very quick Confecution of ons another. And this may bis 
eafily pertorm*3 by the rapid gyration of a Wheel wiih |many 
Spoaks or coggs in its perimeter, whofe Interftices and thicks 
neffes may be equal and of fueha largeiieG^ that, ifthe Wheel 
be' interpo fed 'between .the Prifme and. the white concourfe - 
