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# Title: Opticks: Or, A Treatise Of The Reflexions, Refractions, Inflexions and Colours Of Light (shelfmark Leibn. Marg. 193)
# Folio 10, page id 1677894601:0182
# Original at the GWLB: https://digitale-sammlungen.gwlb.de/resolve?id=1677894601&page=182
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# Model: FoNDUE-GD_v2_ft_Leibniz, run 74, 2026-09-06T16:05:13Z — 34 lines, status machine
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L
and my Fre ras distant Erom it 8 Tnches. And a third
proportional to halt this From the Diameter of the
Sphiere 15 soeso Parts oF an Inch. This is theretore the
chicknels oF the Air atthis Ring, and a titth part there-
ot, viz. the sosioth parc ot an Inch is the thieknels there
OE at the Erst oF the Ringo as above.
Perred the lame thins by lavins these Object-C7lasco
upon Hat pieces of a broken Lookins-glats, and tound
the same meatures oF the Rings: Whuch MakeS ME
rely uxon them till ther can be determined more ac-
curatelr by Cilasses ground to larger Spheres, though
in Cuch Cilases greater care muit De taken OE a FruC
Plaim.
Phele Dimentions wrere taken irhen my Pye WaS
placed almost perpendicularly orer the GlaPes, beins
about an luch, or an lnch and a quarter, distant Erom
the incident rays, and cight luches distant Erom the
Cla(s; (0 that che rays ivere inclined tothe Cilals in an
Ansle ot about 4 degrees. Whence by the Tollorvins
Oblerration rou will understand, that had the rays
been pervendicular to the CElases, the thickneis otthe
Air at these Rings ould hare been less in the PropOr-
tion ot the Radius to the secant oF 4 degrees, that is ot
10000. P et the thicknesses tound be theretore dimi-
nistred in this proportion, and ther vill oecome ssogo and
s Or (to usc the nearest round number) thC sguo th
part ot an Inch. Thisis the thickness oF the Air at the
darkelt part ot che Arst dark Rins made by perpendi-
cular rayS, and hals this chieknels multiplied by the
progreltion, 1,3,597, 9, TI, c. Sires thethicknesles of the
Air at the most luminous parts oE aIl the brishtelt
LII8S, VIZ. 1oS e eces  SC. Theis arithmeticat
MeaNS