MicROGRAPHIAL 
by the refifiance of the tran{parent medina, than the other part or end.of 
it which is fubfequent, whofe way is, as.it were, prepared = the other ; 
efpecially if the adjacent medixm be not in the fame manner enlightned 
oragitated. And therefore(in the fourth Figure of the fixth Iondm )the 
Ray AAAHSB will have its fide HH more deadned by the refiftance 
of the dark or. quiet #edinw: P PP, Whence there willbe a kind of dead- 
nefs fuperinduc d onthe fide H HH, which will continually increafe from 
B, and {trike deeper and deeper into the Ray by the Jine BR. ; Whence 
all the parts of the triangle, R BHO willbe of a dead Blve colour, and 
fo much the deeper, by; how much the nearer they lieto the line BHH, 
which is moft. deaded or impeded, and. fo much the more dilute, by how 
much the riearer it approaches the line BR. Next on the other fide of 
the Ray AAN, theend A of the pulfe AH willbe promoted, or made 
{tronger, having its paflage already prepar'd as ‘twere by the other parts 
preceding,and {o its impreffion wil be ftronger;And becaufe of its obléqui 
zy to the Ray,there will be propagated a kind of faint motion into QQ. 
the adjacent dark or quiet zzedium, which faint motion will {pread fur- 
ther and further intoQ Q_as the Ray is propagated further and further 
from A,namely,as far as the line M A,whence all the triangle MAN will 
be ting'd with a Red, and that Red willbe the deeper the nearer it ap- 
proaches the line MA; and the paler or yel/ower the nearer it isthe line 
NA. Andif the Ray be continued,{o that the lines A N andBR (which 
are the bounds of the Red and Blue diluted) do meet and crofs each other; 
there will be beyond that interfeGtion generated.all kindsof Greens... 
Now.thefe being the proprieties of every fingle refracted Ray of light, 
it will be eafie enough to confider what mutt be the refult of very many 
fuch Rays collateral: As if we fuppofe infinite fuch Rays interjacent be- 
tween AKSB and ANOB, which are the terminating : For in this cafe 
the Ray A KS B will have its Red triangle intire,as lying next to the dark 
or quiet medium, but the other fide of it BS will have no Blve, becaufe 
the medium adjacent to it SB O, ismov'd or enlightned,and confequent- 
ly that light does deftroy thecolour. So likewife will the Ray ANOB 
lofe its Red,becaufe the adjacent medium is mov'd or enlightned,but the 
other fide of the Ray that is adjacent to the dark, namely, AHO will 
preferve its B/ve entire, and thefe Rays muft be fo far produc‘d as till 
AWN andBR cut eachother, before there will be any Greex produc d. 
From thefe Proprieties well confider'd, may be deduc’d the reafons of all 
the Phenomena of the prifme, and of the Globules or drops of Water which 
conduce to the production of the Rainbow. toda dasile 
_. Next forthe impreffion they make onthe Reti#a, we will further ex- 
amine this Hypothefis : Suppofe therefore ABC D EF. jin the fifth Figure, 
to reprefent the of the eye: on the Correa. of which ABC two 
Rays GACH and KCAI (which are theterminating Rays of a Iumi- 
nous body) falling, are by the refraction thereof collected or converg'd 
into two points at the bottom of the eye. Now, becaufe thefé termi- 
ating Rays, and all the z#termediate ones which come oe a part of 
the luminous body, are fuppos'd by fome fafficient refraction betore they 
enter 
63 
