Ibn-al-Haitam, al-Hasan Ibn-al-Hasan; Witelo; Risner, Friedrich, Opticae thesavrvs Alhazeni Arabis libri septem, nunc primùm editi. Eivsdem liber De Crepvscvlis & Nubium ascensionibus. Item Vitellonis Thuvringopoloni Libri X. Omnes instaurati, figuris illustrati & aucti, adiectis etiam in Alhazenum commentarijs, a Federico Risnero, 1572
<head xml:id="echoid-head314" xml:space="preserve" style="it">11. Viſibile & imago à ſpeculi plani ſuperficie in oppoſit {as} partes æquabiliter distant. 49 p 5.</head>
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<s xml:id="echoid-s7765" xml:space="preserve">SIt a punctum uiſum:</s>
<s xml:id="echoid-s7766" xml:space="preserve"> b centrum uiſus:</s>
<s xml:id="echoid-s7767" xml:space="preserve"> c d e ſpeculum planum:</s>
<s xml:id="echoid-s7768" xml:space="preserve"> & ſit d punctum reflexionis:</s>
<s xml:id="echoid-s7769" xml:space="preserve"> c d e
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linea communis ſuperficiei reflexionis & ſuperficiei ſpeculi.</s>
<s xml:id="echoid-s7770" xml:space="preserve"> A puncto d ducatur d f perpendi-
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cularis ſuper lineã cõmunẽ:</s>
<s xml:id="echoid-s7771" xml:space="preserve"> [per 11 p 1] & à puncto a ducatur perpendicularis ſuper ſpeculi ſu
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perficiẽ, [per 11 p 11] quæ ſit a c, & producatur ultra ſpeculũ:</s>
<s xml:id="echoid-s7772" xml:space="preserve"> & a d ſit linea, per quã forma accedit ad
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ſpeculũ:</s>
<s xml:id="echoid-s7773" xml:space="preserve"> b d, per quã reflectitur ad uiſum.</s>
<s xml:id="echoid-s7774" xml:space="preserve"> Igitur b d, f d, a d, ſunt in ſuperficie reflexionis [per 23 n 4.</s>
<s xml:id="echoid-s7775" xml:space="preserve">]
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Et cũ f d ſit æquidiſtãs a c [per 28 p 1:</s>
<s xml:id="echoid-s7776" xml:space="preserve"> quia cũ a c ſit քpẽdicularis ſuperficiei ſpeculi per fabricatiõem:</s>
<s xml:id="echoid-s7777" xml:space="preserve">
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erit perpẽdicularis lineę c d e per 3 d 11] & [per 13 p 11] d b declinata ſit ſuper f d, cõcurret [per lemma
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Procli ad 29 p 1] b d cũ a c.</s>
<s xml:id="echoid-s7778" xml:space="preserve"> Cõcurrat ergo in puncto g.</s>
<s xml:id="echoid-s7779" xml:space="preserve"> Dico, quòd g c eſt æqualis c a.</s>
<s xml:id="echoid-s7780" xml:space="preserve"> Quoniã enim