But, foppoUng that all Cohms might ^o.cc aiding t© eliil e^' 
p^riaieDtjbe produced out of ttmhy mixture ^ yet if follow^ 
DGtj that ihofe two are the only On^^W/ coIours5 and that fo- 
a double reafon, i^?>y?5 becaufe thofe two m€ not themfelve^ 
Origioal colourSj but compounded ofothers 5 there being 00 
liquor nor any other body in nature,whGfe colour io Day. light 
is wholly un-corapounded* And then^ becaufe^ though thofe 
two were Original^ and all others might be compounded of 
them^ yet it follows not, that they cannot be otherwifc produi? 
ced* For I faidj that they had a double Origin^ the fame Cc- 
lours to fenfe being in fome cafes compounded and in others 
un compounded ; and fufficienily declarM io my i'te^ fedv 
fmrtb Propofitions, and in the Conclnfion^ by what Properties 
the one might be known and diftinguifli^rfrom the other. Buc^ 
becaufe I fufpedby fome Circumftances, that the DijlinUton 
might not be rightly apprehended, I fllall once more declare 
it, and further explain it by Examples. 
That Colour is Primary* or Original^ which cannot by any 
Art bechangedvand whole Rays are nct ».% refrangible : 
And that Compouritied^ which is changeable into other coloursy 
and whofe Rays are net alikg refrangible. For infiame^^ to 
knoWi whether the colour of any Green objedbe compound 
ded or notj view- it through a Prinej and if it appear conjafed^^ 
and the edges tinged mthBlerv^ TeHow^ ot any variety of o- 
ther colours, then is that Gww compounded of fuch colours 
as at its edges emerge out of it : But if it appear rf//?jff/E. and 
well defin'dj and entirely Green to the very edges, without 
any other colours emerging^ it is of an Original and un-com- 
pounded Green. In like manner, ifa refraded beamof lightj 
being caii on a white wall, exhibit a Gr^i??^ coiour, to know^ 
whether that be compounded, refrad: the beam with an in- 
terpofedprifmef and if youfind any DifFormicy io the refra 
caionsg and the Grmi be transform'd into Blerv^ YeSompt any 
variety of other colours, you may conclude, that it was com-^ 
pounded of thofe which emerge: But if the Refraaions be 
UDiformj and the Gr^^^ perfift without any change ofcoldur. 
then is it Original and un compounded^ Andche reafon why 
I c^ll it fa, is, becaufe a Green indued with fuch properties can- 
not be produced, by any mixing of other coloars. 
