Opticks 1717 - Up

E
0.7 .
‘p T is compofed, and whidh in the middle parts
of the SpeCkrum interfere and are intermix’d
with1 one another, are not internnix’d in their
otitmofi parts ,where they t0UCh thOi’b re&ilinear
fides A H; and G ,M. Aud tl~rcfbre in
thofe re&jl,inear fides when diil:intl.ly defined,
there is 110 new Colour gelleraWd by Refix-
,Ction. 1 obferved alib, that if ally where between
the two outmo[I Circlks ‘r b’l I! ’ and
P GA a right Line, as y $, Was crofs to the
+e&rum, fo as at @t-h end,s to Ml perpendi*
cdarly upon its ro&linear ildes, thCV2 appcared
ogle arld the ilttieColour and degrCC of colour
from 01x2 end of tl1i.s Line to the other. I
&&leated therefore in a I%ycr tk perimcrer
cjf the SpeRrum FA.P G M’I’, ‘and in tr ing
the third Experinxnt ‘of t-tic firik I:,oo~, 1 kid
the Paper ii, that the f$x&um might Ml upon
this delineated Figure, and agree with it cxa&-
ly, whilft an AiIibt vr7hok Eyes fbr difiinguiking
Colours were more critical than nlinc, did
by right’lines CL/~, y 1, EC; @e. drawn crofs the
Spe&rurn , note the Corlfines .of the Colo~ris,,
that is of the red .&$ CE (427, of the orang CL 3 60,
of ‘the yellow +J E gs, of 1-1x grew E k-j 0 c, of the
blue 111 IC 8, of the illdico L h ,U JC, and ot i:hC violet
~G!,G. And this O,pcratinn~ bci ng divm
rimes repeated bdth in the fkme and i.n feveral
Papers, I found that the Obfervations agreed
well enough with one another, and that the n
xektilinear fiqks M G and F‘ A. WCE by rhc hid
crofs Lines divided after the manner of a. mufical
Chord. Let GM be roduccd to X, th&
M X may be equal to 6