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# Title: Opticks: Or, A Treatise Of The Reflexions, Refractions, Inflexions and Colours Of Light (shelfmark Leibn. Marg. 193)
# Folio 60, page id 1677894601:0070
# Original at the GWLB: https://digitale-sammlungen.gwlb.de/resolve?id=1677894601&page=70
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Angle of Retraction, which is cheretore 53 deg. 35 min. and
itS Sine 8047. These are che sines ot Incidence and RC-
traction of che mean retransible Rays, and cheir proportion
in roundnum bersis 201031. This Classmas oF a colourir-
clininq to oreen. The last of che Prilims mentioned in the
chird Lxperimene as ot clear irhice Clals. Ies retractine
Angle 63: deorees. The Angle. which the CMeKGCNE R ayS
concained, ich che incident 15 deg. 50 min. The Sinc ot
halF che First Angle 5262. The Sine oF halt che Sume
OFthe Anoles 8157. And cheir proportion in round num-
bers 20 10 31 a5 betorc.
From che Lensch oE che Image, ihich as about 92 Or
10Tnches, Fubduet its Breadch; Which Was 2 Inches, and
the Remainder 73 Tnches vould beche lenethofche Image
ivere the sun buc a pome, and cheretore subcends the An-
ole irhich che most and least retransible Rays, when inci-
dent on che Prism in che lame Lincs, do contain with one
anocher atter cheir Emergence. Whence chis Anole is
2 deg. 0. 7. For che distance betreen che lmageand the
Prilm nhere chis Angle is made, Was 18 = Feet, and ac chiac
distance the Chord 7? Inches subtends an Angle ol 2 deg.
0. 7. NTow half chis Angle is che Angle wrtich chele e-
mergent Rays contain ich che emergene mean retrangible
RayS, and a quarter chereot, that is 30. 2. may bc ac-
counted che Angle which cher rould concain irhich ehc
Tame emergene mean retrangible Rays, ivere ther coninci-
dene eo ehem ichin che Class and (uftered no octer Re-
Fraction chen thac at their Emergence. For if erro equal
Refractions, the one ac the incidence of che R WVS on the
Prism, the ocher ac their Emergence, makce half the Angle
2 deg. 0. 7. then one ot thole Retractions ill make
aboue a quarter ot thac Angle, and this quarter added to
aA