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# Title: Optica Promota, Seu Abdita radiorum reflexorum & refractorum Mysteria, Geometrice Enucleata (shelfmark Leibn. Marg. 94)
# Folio 49, page id 727094130:0061
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FOD. 38.
Theorema
Si visibile mistat radios parallelos, insphaeroidem densiratis; erunt api-
ces penicillorum, sinculorum visibilis punctorum, in uno quam proxi-
me plano.
Le Sphaerois densicaris A R C B, Cusus aris CC producetur ad
L DFOcum remOLIOrEM M; e per M ducacur planum I. M TH.
cui normalis scaxis C CM. Dico omnes apicespenicillorum,
exradiis in sphaeroidem parallele incidencibus, ortorum, cadere
quam proxime in planum L M T N. Sic enim unius penicilli
aris FR, normalicer incidens in spharoidis superticiem in puncto
R; e per axem sphaeroidis e penicilli, ducatur planum, Faciens
cum sptaeroide communem sectionem ellipsen A R C B, ex qua
veneratur; cum plano
verOL MTNI, rectam
LM TN; X per pun-
Ctum R, duCACuE una
recta ORO, cangens
ellipsem, _ axi Oc.
currens in O; alia ve-
FO K R, axi ellipleos
Parallela, quae igicur
retringetur in focum
M. seu apicem peni-
cilli radiorum axi pa-
Fallelorum: ducacurq.
per verricem ellipleos
C, recta TC, ipAF R,
Paralleloz quae ideore-
Fringetur in I, apicem
Penicilli, Radiorum
ip(I F R Parallelorum:
Fx quoniam angulus incidenriae IC P, est aequalis angulo inciden-
ciX F RK; erit _ angulus refractionis RHC, angulo refractio-
nis RM C aequalis; crunrq;e triangula C C H, C R M similia; d
 juts
1uS