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# Title: Opticks: Or, A Treatise Of The Reflexions, Refractions, Inflexions and Colours Of Light (shelfmark Leibn. Marg. 193)
# Folio 28, page id 1677894601:0038
# Original at the GWLB: https://digitale-sammlungen.gwlb.de/resolve?id=1677894601&page=38
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# Model: FoNDUE-GD_v2_ft_Leibniz, run 74, 2026-09-06T16:05:13Z — 34 lines, status machine
# Lines: 34 recognised, mean confidence 0.93
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I considered Furcher chac by che breadch ot the hole F
chrouoh wrhich che Lighe enters into the Darke Chamber,
there is a Penumbra made in che circuie ot che Spectrum
T, and chac Penumbra remains in the rectilinear Sides ot
the Spectrums P Pand pt. I placed cheretore ac char hole
2 Lens or Object. glals ot a l’elelcope itich miohe cast
che Image ot the sun distinetly on Y wichout any Penum-
bra ac aIl, and Found chac che Penumbra ot the Rectili-
near Sides oF the oblons Spectrums P T and pt vas allo
cherebr cakcen arar, (o chac chole Sides appcared as di-
Rinctir detired as did che Circumterence ot the trst Imaoe
Y. Thus ic happens it che Olass of the Prilms be free
trom veins, acd cheir Sides be accuratetr plane and vell
polished wichoue chole numberlels vares or curles irtrich
ulually arise trom Sand holes a licele smoothed in polist-
ino wich PuteY. IE ehe Class be ouly well polished and
Frec trom reins and che sides noc accurarely plane bue a
licele Conrex or Concare, 25 ic trequeney happens; rec
may chethrec Spectrums Y, P I and pt manc Penumbras,
buc noc in equal distances trom che Prisms. No From
this mane et Penumbras, Ikneu more certainty chac every
one ot the circles as retracted accordine co lome most
regular, uniform, and constane lar. For il chere ivere
any irregularier in cheRetraction, che riohe Lines AC and
OL irhrich all che circles in the spectrum P Y do touch.
could noc br chac Retraction be translaced into che Lines
ae and el as dictinet and sraiohe as they vere betore, buc
chere mould arise in chose cranslated Lines Lome Penubra
or croolcednels or undulation, or ocher sensible Percurba-
eion contrary ro whac is tound by Experience. Whaclo-
ever Penumbra or Percurbation Bould be made in che
circles by the cross Retraction ot the sccond Pris, aII
that Penumbra ox Perturbation rould De conspicuous in
che