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# Title: [Lectiones XVIII, Cantabrigiae in Scholis publicis habitae] Lectiones XVIII, Cantabrigiæ in Scholis publicis habitæ (shelfmarks Leibn. Marg. 0; ZEN Leibn. Marg. 0)
# Folio 18, page id 797435492:0034
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P. F C T. II
reflectionis leges examussim obserrat. Nam quoniam iloscelis criari.
suliZ B6 anguli Z B6, Z6 B sunt aequales, etiam anguli (de rectis
relidui) ABF, a6P pares erunt; quod reflectioni proprium est.
ltaque non abs resto pronunciant hoc Dioptrici; neque tamen cauland.
Forractis ab iispraetermiltam, racere volui, nonnihil ab immediatae re-
Rectionis causa direrlam; ne quisquam haesitet, aut hoc adlumenti
gravetur concedere.
VII. Elac autem doctrina cum multis experimentis necunque com
probari queat, unum salcem brerire attingam latis illustre, neminisq.
non examini patens. Fstotriangulum A B C sectio prismacis trianou
laris xequilateri (nimirum vitrei, seu crystallini) bali parallela; in hu-
sus autem bale sumatur punctum quodpiam F, _ (IE angulus CF
circiter graduum 50. (unde juxra doctrinam hic insinuatam, _ poltea
clarius expeimendam radius F velut extremus cric corum, qui re-
Etx BC. e rieri partibus illabentes refractionem parientur; eo scilicet
obliquior quilibet refectetur.) Sic igitur (quoniam utramque quali
patitur inflectionem) ejus retractus FM, retlexus F F; item PC re-
Fringatur in C5O, _ F F in FR. Porro jam in CO Catuatur oculi
centrum O; et ab eo prodeat radius OC, qui retringatur in OP.
iptorum OC, OO retracti GF, OP (uti secundum principia no-
Pra Posthac constabit) progredientes divergent; eritque propterea
ang. OPC L OFC; quare radius (YP medium BC penetrabit,
ac retringetur, puta in P N; liquebit aurem e dicendis retractos PM,
P N a se diversere; Hinc jam radiis M F, NV P interpolicum objectum
radiisOC, O Q interjectum apparebit, velur ad ur, situ neutiquam
immutatum. Rursus aurem ab oculi disto centro prodeat alter radius
OK, cujus refractus (I RI; hic itaque rursum a CF direrget, ac
inde exit ang. RIF = ang. C F C; adeoque R L minime penetrabit
edium B C, at refectetur, puca in LH; cum l. HL retringatur in IIS.
Ergo jam radiis E R, HIS incerjacens objectum puta RS radiis 6,
OK incerjectum cernetur, velut ad 5o, litu partium cverto. C onse-
quuntur haec doctrinam nostram, ex experientia liquido consentanea
deprehendentur, quin ex observatu dignum erit, e duplici retractione
spectatum obieetum MEI Tridis coloribus tinctum adparere (rubro
scilicet ad us exruleo adr, croceo medium occupante) objecti vero
Se duplici retractione, sed refectione tamen intercedente, appre-
henli iriasinem so colore nihil ab ipso objecto ditterre. Ouod ex co
Tane videtur evenire, quoniam ars. FF B angulo FC, C aequatur.
adecique radtius RO non alitex evirro exit, quam R F insrectus est:
se
Xept. prOB 4