Opticks 1717 - Up

the ~IO$OII and to the par&l edges of the
paper DJ and WE, and the tranfverfe LineFG
is pcrpdicular to the Piane of the ?Kndo~~,
AIld de ~ep&ms the Lnqe of the Paper ken
l)y &fr&ion uptTmds in iuch manner that the
blue hlllf 10 G is carried higher to dg than the
red llillf FE is to fe, and therefore furers a
grcMXr RCfi-ilEtiOl1. If the edge of the refra&
jng AI& be turlled downward9 the Image of
the &per n;ilI bc refraAed downward, f~ppofe
to J,, and the blue half will be refraAed lower
to $y than the red half is to Q E.
~x~‘Pv~, 2. About the aforeiid Paper9 whofe
two ha1y!‘s were painted over with red and blue,
and \I-hich was Mf like thin Paitboard, E lapped
kveral times a fl cnder thred of wry black Silk,
in fuch manner that the feveral parts of the
thred might appear upon the Colours like fo
rnaq~ black Lines drawn over them, or like
10x1~ and flender dark Shadows cafk upon them.
1 ,mlght have drawn black Lines with a Pen,
but the threds ~crc finallc~ and better defined.
This Paper thus colourcd and lined 1 fet againfi
a %‘a11 perpendicularly to the Horizons fo that
one of the Colours might Oand to the right
hand, and the other to the left. ‘Clofe before
the Papey tit the co&he of the Colours below
1 placed a Candle to illuminate the Paper ikongjy
: jt;‘or the &periment was tried in the
‘Ihe flanw of the Candle reached up to the
loser edBe of the Paper, or a very little hioher.
‘Then at the diitance of fix Feet and one oPt~70
hdmcs fkm the Paper upon the Floor I ere&ed
a &p-lS Lens four Inches and a quarter broad,
which