Now, these being the proprieties of every single refracted Ray of light, it will be easie enough to consider what must be the result of very many such Rays collateral: As if we suppose infinite such Rays _interjacent_ between AKSB and ANOB, which are the terminating: For in this case the Ray AKSB will have its _Red_ triangle intire, as lying next to the dark or quiet _medium_, but the other side of it BS will have no _Blue_, because the _medium adjacent_ to it SBO, is mov’d or enlightned, and consequently that light does destroy the colour. So likewise will the Ray ANOB lose its _Red_, because the _adjacent medium_ is mov’d or enlightned, but 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 _Phænomena_ 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.