Opticks 1717 - Up

&fed and illdiI?inPt, -that I could IIO~ read them :
Viihoreupo~~ yicwing the Priful, 11 fOLmd it was
fIJ1 of \t’cins running from One end Of the Glafs
to the other; ii, tlm the RcfraC’rion could not
be IT~-L&I~. I taoI; another Ptifin therefore
which uqs f&e fromVeins, and initcad of the
Letter.s 1 u&d two or three pxallel black Lines
:I little broader than the itroakcs of the Letters,
and cadting the Colours upon thefe Lines
in ii~h 17x1l111cr t-hat Ehe Lines ran along the
Colours fi-0111 one end of the §pe&wn to the
other, I fot:nd that the 9;1o~u~~lwe the indigo,
or CCXI~-~IK of this Colour md violet cait the
Species of the black Lines n~oit diitin&Iy, to
be about four Inches or +; nearer to the Letis
than the Focus where the deepeft red caft the
Species of the fan-~ black Lines n~oft diitin&-
ly: The violet was fo fAint and dark, that I
could not difccrn the $xcies of the Lines diil-in&y
by that Colour ; and therefore co&-
dering that the Priiin was made of a dark col&-ed
GIafs inclining to qrecn,.I took another
Prifin of clear white GM\; but the Sp&rum
of Colours which rhis Prifin mad,e had long
UThite itrealns of faint Lighr ihooting out fixin
both ends of the Colours, which made lne concfudc
that ibmething was amii‘s; and viewillg
~-3~ PI-ilin, I found two or three little bubbles
3-11 the Glaij; which refia&d the Light irregula+y.
Wherefore I covered that part of tile Glafs
vmh black Paper ) and letting the Light pafs
~tlirough another part of it wlti’& was free from
fuch bdhlcs, the Spe&um of C3010urs became
fine fro111 ~hof$ irregular Streams of Light, and
was