icS8 ) 
lors a white which to the naked eye fhall appear like other 
whues, but alfo fc^ them in all other propcr- 
But to let you underftand wherlin fuch a white vtouM 
differ from other whites and why from thence it would fol- 
low that other whites arc Othcrwife compounded 5 I flbal! Jay 
down this pofitioDt 
Jhat a compounded color can he refolved into no more jimpk co^ 
, tors then thofe of rohich it is compounded, 
A 
This feeois to be felf evident 5 and I have alfo tryed it feve- 
ral ways, and particularly by this which 
fellows. Let esreprefent an oblong piece A ^ 
of white*paper about tor | of an inch J'"" ] fZZ~~! 
^troad5and illuminated in a dark room 
with a mixture of two colours caft upon B 
it from two Prifeis, fuppofe a deep blew 
tnd fcarlct, which muft fcverally be as 
uncompounded as they can convenient- 
ly be made. Then at a convenient di* 
ftancCjluppofe of fix or eight yardSjView 
it through a clear if iangularglafs or cry ftal Prifm held paral- 
lel to the paper, and you (hall fee the two colors parted from 
one another in the fafliion of twoimagesof the paper^as they 
are reprefented at ^ and >, where fuppofe thefcarlet and 5^ 
the blew 5 without green or any other color between 
them. 
Now from the aforefaid Pofition I deduce thefe two con- 
clufions. That if there were found out a way to compound 
white of two fimple colors onlyjthat white would be again re- 
foivablc into no more than two. a. That if other whites ("as 
that of the Suns lights &€. be refolvable into more thaa two 
fimple colours (as I find by Experiment that they are^ then 
they muft be compounded of more than two. 
To make this plainer, fuppolc that A reprefents a white bo- 
dy illuminated by a dired beam of theSun tranfmitted through 
a fmall hok into adarkrooro^ and tf fuch another body illu- 
minated by a mixture of two .fimple colors^ which if pofiible 
may 
iiiiiiiiii 
llllllllll!! 
