upon different points in the bottom of the Eye, and their trembling
Motions are too quick and confused to be perceived severally. And all
these illuminated Points constitute one broad lucid Point, composed of
those many trembling Points confusedly and insensibly mixed with one
another by very short and swift Tremors, and thereby cause the Star to
appear broader than it is, and without any trembling of the whole. Long
Telescopes may cause Objects to appear brighter and larger than short
ones can do, but they cannot be so formed as to take away that confusion
of the Rays which arises from the Tremors of the Atmosphere. The only
Remedy is a most serene and quiet Air, such as may perhaps be found on
the tops of the highest Mountains above the grosser Clouds.
FOOTNOTES:
[C] _See our_ Author's Lectiones Optic 10. _Sect. II. 29. and Sect.
III. Prop. 25._
[D] See our Author's _Lectiones Optic _, Part. I. Sect. 1. 5.
[E] _This is very fully treated of in our_ Author's Lect. Optic. _Part_
I. _Sect._ II.
[F] _See our_ Author's Lect. Optic. Part I. Sect. II. 29.
[G] _This is demonstrated in our_ Author's Lect. Optic. _Part_ I.
_Sect._ IV. _Prop._ 37.
[H] _How to do this, is shewn in our_ Author's Lect. Optic. _Part_ I.
_Sect._ IV. _Prop._ 31.
THE FIRST BOOK OF OPTICKS
_PART II._
64