ment. But this, I conceive, is enough to enforce it, and fo to de- 
cide ttie concroverfy. Hour-ever, I Ihall now proceed to ftew forae 
other ways of producing TVhhenefs by mixtures^ {xxxct I perfwade my 
felf, that this Affertion above the reft appears Faradosical, and is 
with moft difficulty adoiitted. And becaufe the Anmadverfor ddir^s 
an inftancc of it in Bodies of divers colours^ I ftiall begin with that. 
But in order thereto itrauftbe confider'd, that fuch colour d Badies 
refledbutfome part of the Light incident on them ^ as is evident 
by the 13 Pfopofition : And therefore the Light refleded fro® an Ag-- 
gregat of them will be much weakned by the lofs of many rays.' 
Whence a perfed and intenfe Whitenefs is not to be expeded, but 
rather a Colour between thofe of Light and Shadow, or fucli a 
Gray or Dirty colour as may be made by mixing White and Black 
together. 
And that fuch a Colour will refult, may be colleded from the 
colour of Z)/^/ found in every corner of an houfe, which hath been 
obferv*d to confift of many colourM particles. There may be alfo 
produced the like Dirty colour by mixing feveral Painters colours 
together. And the fame maybeeffeded by Painting a Top (fuch 
as Boys play with J of divers colours. For, when it is, made 
to circulate by whipping it, it will appear of fuch a dirty co- 
lour* 
Now, the Compounding of thefe colours is proper to my pur- 
pofe, becaufe they differ not from Whitenefs in the Species of co-. 
lour, but only in rfifg'rd'i? of Luminoufnefs which f did not iht An^ 
imadverfor concede it) I might thus evince. A beam of the Suns 
Light being tranfraitted into a darkned room, if you illuminate a 
fiieet of White Paper by that Light, refledcd from a body of a- 
By colour, the paper will always appear of thc/colour of that bo- 
dy, by whofe refleded light it is illuminated. If it be a red bo« 
dy, the paper will be red, if a green body, it will be green? and fo 
of the other colours. The reafon is, that the fibers or threds, of 
which the paper confifts, areall tranfparent and fpecular 5 and fuch 
fubftances are known to refled colours without changing thera. Tq 
know therefore, to what Species of colour a Grey belongs, place a- 
ny Gray body(fuppofe a Mixture of Painters colours ^)in the faid Light,' 
and the paper, being illuminated by its reflexion, fhall appear White* 
And the fame thing will happen, if it be illuminated by reflexion 
from a ^/^c'^fubfl:ance» ' 
Thefe therefore areall of one Speties but yet they feera diftin- 
guiflitnot onlyby <^f^wjof Lumi?tioufnefs, but alfo by fome other 
Inequalities, whereby they become more harfli or pleafant. And the 
diftindion feems io be, that Greys and perhaps Blacks trc made by an 
uneven defed of Light, confifting as it were of many little veins 
or flreams, which difter either in Luminoufnefs or in the Unequal di- 
Mmmmra ' ftribution 
