shall happen, if the Paper be placed about Kk, for towards T shall appear a
_Red_, and towards V a _Blue_, which does exactly agree with this my
_Hypothesis_, as upon the calculation of the progress of the pulse will
most easily appear.

Nor do these two observations of the colours appearing to the eye about p
differing from what they appear on the Paper at N contradict each other;
but rather confirm and exactly agree with one another, as will be evident
to him that examines the reasons set down by the ingenious. _Des Cartes_ in
the 12. _Sect._ of the 8. _Chapter of his Meteors_, where he gives the true
reason why the colours appear of a quite contrary order to the eye, to what
they appear'd on the Paper if the eye be plac'd in steed of the Paper: And
as in the Prisme, so also in the Water-drop, or Globe the _Phænomena_, and
reason are much the same.

Having therefore shewn that there is such a propriety in the _prisme_ and
water _Globule_ whereby the pulse is made _oblique_ to the progressive, and
that so much the more, by how much greater the refraction is, I shall in
the next place consider, how this conduces to the production of colours,
and what kind of impression it makes upon the bottom of the eye; and to
this end it will be requisite to examine this _Hypothesis_ a little more
particularly.

First therefore, if we consider the manner of the progress of the pulse, it
will seem rational to conclude, that that part or end of the pulse which
precedes the other, must necessarily be somwhat more _obtunded_, or
_impeded_ by the resistance of the transparent _medium_, than the other
part or end of it which is subsequent, whose way is, as it were, prepared
by the other; especially if the adjacent _medium_ be not in the same manner
enlightned or agitated. And therefore (in the fourth _Figure_ of the sixth