Barrow, Isaac
,
Lectiones opticae & geometricae : in quibus phaenomenon opticorum genuinae rationes investigantur, ac exponuntur: et generalia curvarum linearum symptomata declarantur
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jam aliquoties inſinuatâ; </
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<
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<
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">& </
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<
s
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xml:space
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">deſignetur quilibet refractus KN; </
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<
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BN; </
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<
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<
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<
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<
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<
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catur recta PZ ad AB parallela; </
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<
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<
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nullum alium refractum per Z traſire. </
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<
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xml:space
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alius ZR; </
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<
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<
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ſtratis apparet quòd ſit RS = NG. </
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<
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quò RS &</
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refractus KN; </
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GN, ad ipſas NG, GB ſumatur tertia proportionalis V; </
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NG. </
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<
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rallela refractum NK decuſſans in Z; </
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per ipſum Z meare. </
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Y trajiciatur RY S; </
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- Iq. </
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<
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NGq . </
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<
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deducitur eſſe BP quartam proportionalem in ratione YP ad PN ; </
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conſequentérque fore RS minimâ NG majorem . </
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<
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ſatur oſtenſis . </
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<
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Q. </
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<
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ad rectiorem pertinens incidentem (hoc eſt ut incidentiæ punctum M
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inter B, & </
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(ſeu perpendiculari KB propinquior) . </
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<
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pendicularis XQ. </
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<
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M, Y traducatur recta MY H. </
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<
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quæ per Y angulo XQF interſeri poſſuntinter puncta M, N cadet
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(utì nuper admonitum, & </
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BP quarta proportionalis in ratione YB ad BN ; </
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<
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proportionalis in ratione YB ad B φ, erit PB &</
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<
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recta XQ rectis ZP, KB interjacet : </
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<
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Q X. </
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<
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<
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<
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<
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minima per γ ducibilium angulo AB F intercipienda punctis M, N
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intercider; </
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<
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<
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γ Qad Q φ; </
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<
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<
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<
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