sarily be A, as being farthest remov'd from the heat, all the
intermediate spaces will be gradually discriminated by the continuall
mixture of heat and cold, so that it will be hotter at EE, then DD, in DD
then CC, in CC then BB, and in BB then A. From which, a like refraction and
condensation will follow, and consequently a lesser or greater refraction,
so that every included part will refract more then the including, by which
means the Rays, GKI, GKI, coming from a Starr, or some remote Object, are
so inflected, that they will again concurr and meet, in the point M. By the
interposition therefore of this desending vapour the visible body of the
Star, or other Object, is very much augmented, as by the former it was
diminished.

From the quick consecutions of these two, one after another, between the
Object and your eye, caused by their motion upwards or downwards,
proceeding from their levity or gravity, or to the right or left,
proceeding from the wind, a Starr may appear, now bigger, now less, then
really it would otherwise without them; and this is that property of a
Starr, which is commonly call'd twinkling, or scintillation.

The reason why a Star will now appear of one colour, now of another, which
for the most part happens when 'tis neer the Horizon, may very easily be
deduc'd from its appearing now in the middle of the vapour, other whiles
neer the edge; for if you look against the body of a Starr with a
_Telescope_ that has a pretty deep _Convex_ Eye-glass, and so order it,
that the Star may appear sometimes in one place, and sometimes in another
of it; you may perceive this or that particular colour to be predominant in
the apparent Figure of the Starr, according as it is more or less remote
from the middle of the _Lens_. This I had here further explain'd, but that
it does more properly belong to another place.

I shall therefore onely add some few Queries, which the consideration of
these particulars hinted, and so finish this Section.

And the first I shall propound is, Whether there may not be made an
artificial transparent body of an exact Globular Figure that shall so
inflect or refract all the Rays, that, coming from one point, fall upon any
_Hemisphere_ of it; that every one of them may meet on the opposite side,
and cross one another exactly in a point; and that it may do the like also
with all the Rays that, coming from a _lateral_ point, fall upon any other
_Hemisphere_; for if so, there were to b