the other
side of the Ray that is _adjacent_ to the dark, namely, AHO will preserve
its _Blue_ entire, and these Rays must be so far produc'd as till AN and BR
cut each other, before there will be any _Green_ produc'd. From these
Proprieties well consider'd, may be deduc'd the reasons of all the
_Phaenomena_ of the _prisme_, and of the _Globules_ or drops of Water which
conduce to the production of the Rainbow.

Next for the impression they make on the _Retina_, we will further examine
this _Hypothesis_: Suppose therefore ABCDEF, in the fifth _Figure_, to
represent the Ball of the eye: on the _Cornea_ of which ABC two Rays GACH
and KCAI (which are the terminating Rays of a luminous body) falling, are
by the refraction thereof collected or _converg'd_ into two points at the
bottom of the eye. Now, because these terminating Rays, and all the
_intermediate_ ones which come from any part of the luminous body, are
suppos'd by some sufficient refraction before they enter the eye, to have
their pulses made _oblique_ to their progression, and consequently each Ray
to have potentially _superinduc'd_ two proprieties, or colours, viz., a
_Red_ on the one side, and a _Blue_ on the other, which notwithstanding are
never actually manifest, but when this or that Ray has the one or the other
side of it bordering on a dark or unmov'd _medium_, therefore as soon as
these Rays are entred into the eye and so have one side of each of them
bordering on a dark part of the humours of the eye, they will each of them
actually exhibit some colour; therefore ADC the production of GACH will
exhibit a _Blue_, because the side CD is _adjacent_ to the dark _medium_
CQDC, but nothing of a _Red_, because its side AD is _adjacent_ to the
enlightned _medium_ ADFA: And all the Rays that from the points of the
luminous body are collected on the parts of the _Retina_ between D and F
shall have their _Blue_ so much the more _diluted_ by how much the farther
these points of collection are distant from D towards F; and the Ray AFC
the production of KCAI, will exhibit a _Red_, because the side AF is
adjacent to the dark or quiet _medium_ of the eye APFA, but nothing of a
_Blue_, because its side CF is _adjacent_ to the enlightned _medium_ CFDC,
and all the Rays from the intermediate parts of the luminous body that are
collected between F and D shall have their _Red_ so much the more diluted,
by how much the farther they are distant from F towards D.

Now, becaus