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

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[41] h t a d ſ s g k b e
[42] a b h e d z
[43] b a g q t d z e h
[44] a g b e d z t q h
[45] b g a t z d h
[46] a h b e g p d z n q
[47] h a b e g p d z n q
[48] a h b e g p f d z n q
[49] x e g k z a d
[50] g m h z p b d a k
[51] t g p b h i z d a k s
[52] g z f h a b d c q e k ſ r
[53] m t n q h b f e z p d a g
[54] b ſ d h f r g z q t e a
[55] a d q c m x b g p o k t f z h
[56] a d k u m r h b g i l f e o z t y
[57] a d u m b g o e q s z h p
[58] a d u m c g b o t q p n z h
[59] b k a p f m e l z g t r o q h n d
[60] b k u a p e g t q n d
[61] b d a f e g c
[62] q a e g
[63] a z g e b q
[64] d q g h a z b
[65] k t o z m u y f c l z
[66] q d g e a b
[67] q d n e g h a b
[68] d q n g a e h b
[69] a g e b d
[70] h n t f x q c u p m z ſ
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          <p>
            <s xml:id="echoid-s842" xml:space="preserve">
              <pb o="13" file="0019" n="19" rhead="OPTICAE LIBER I."/>
            bus uerticationibus:</s>
            <s xml:id="echoid-s843" xml:space="preserve"> & ſunt uerticationes linearum rectarum, quarum extremitates concurrunt a-
              <lb/>
            pud centrum uiſus tantùm.</s>
            <s xml:id="echoid-s844" xml:space="preserve"> Et iſtæ lineæ appropinquantur in centro, quia ſunt diametri eius uiſus
              <lb/>
            ſcilicet, & perpendiculares ſuper ſuperficiem uiſus ſentientis.</s>
            <s xml:id="echoid-s845" xml:space="preserve"> Et ſic erit ſenſus ex formis uenienti-
              <lb/>
            bus ex rebus uiſis, & erunt iſtæ lineæ quaſi inſtrumentũ uiſus, per quod diſtinguẽtur à uiſu res uiſæ,
              <lb/>
            & per quod ordinabuntur à uiſu partes cuiuslibet rerum uiſarum.</s>
            <s xml:id="echoid-s846" xml:space="preserve"> Et quòd eſſe uiſus appropriatur
              <lb/>
            aliquibus uerticationibus tantùm, habet ſimilia in rebus naturalibus.</s>
            <s xml:id="echoid-s847" xml:space="preserve"> Quoniam lux oritur ex cor-
              <lb/>
            poribus luminoſis, & extenditur ſuper uerticationes rectas tantùm, & non extenditur ſuper lineas
              <lb/>
            arcuales aut tortuoſas.</s>
            <s xml:id="echoid-s848" xml:space="preserve"> Et corpora ponderoſa mouentur ad inferius motu naturali ſuper lineas re-
              <lb/>
            ctas:</s>
            <s xml:id="echoid-s849" xml:space="preserve"> non ſuper lineas curuas, aut arcuales, aut tortuoſas:</s>
            <s xml:id="echoid-s850" xml:space="preserve"> nec tamen mouebuntur ſuper omnes li-
              <lb/>
            neas rectas, quæ ſunt inter ea & ſuperficiem terræ, ſed ſuper lineas rectas proprias, quę ſunt perpen
              <lb/>
            diculares ſuper ſuperficiem terræ & diametrũ eius.</s>
            <s xml:id="echoid-s851" xml:space="preserve"> Et corpora cœleſtia mouẽtur ſuper lineas ſphæ.</s>
            <s xml:id="echoid-s852" xml:space="preserve">
              <lb/>
            ricas, & non ſuper lineas rectas, neq;</s>
            <s xml:id="echoid-s853" xml:space="preserve"> ſuper lineas diuerſi ordinis.</s>
            <s xml:id="echoid-s854" xml:space="preserve"> Et cum fuerimus intuiti motus na
              <lb/>
            turales, inueniemus, quòd quilibet eorum eſt appropriatus aliquibus uerticationibus tantùm.</s>
            <s xml:id="echoid-s855" xml:space="preserve"> Nõ
              <lb/>
            eſt ergo impoſsibile, ut ſit uiſus appropriatus in receptione operationum lucis & coloris aliquibus
              <lb/>
            uerticationibus rectis, quæ concurrunt apud eius centrum tantùm, & ſunt perpendiculares ſuper
              <lb/>
            ſuperficiem eius.</s>
            <s xml:id="echoid-s856" xml:space="preserve"> Comprehenſio autem uiſus de rebus uiſis ex uerticationibus linearum rectarum,
              <lb/>
            quarum extremitates concurrunt apud centrum uiſus, eſt conceſſa à mathematicis, & nulla diuerſi
              <lb/>
            tas eſt inter eos in hoc:</s>
            <s xml:id="echoid-s857" xml:space="preserve"> & iſtæ lineæ uocantur ab eis lineæ radiales.</s>
            <s xml:id="echoid-s858" xml:space="preserve"> Et cum hoc ſit poſsibile, & for-
              <lb/>
            mæ lucis & coloris ueniant ad uiſum, & pertranſeant per diaphanitatem tunicarum uiſus, & uiſio
              <lb/>
            non compleatur ex receptione iſtarum formarum, niſi quando uiſus receperit ipſas ex uerticatio-
              <lb/>
            nibus tantùm:</s>
            <s xml:id="echoid-s859" xml:space="preserve"> uiſus ergo non comprehendit luces & colores rerum uiſarum, niſi ex formis uenien-
              <lb/>
            tibus ad ipſum ex ſuperficiebus rerum uiſarum, & non comprehendit iſtas formas, niſi ex uertica-
              <lb/>
            tionibus linearum rectarum, quarum extremitates concurrunt apud centrum uiſus tantùm.</s>
            <s xml:id="echoid-s860" xml:space="preserve"> Aggre
              <lb/>
            gemus ergo modò ea, quæ poſſunt aggregari ex omni, quod diximus, & dicamus:</s>
            <s xml:id="echoid-s861" xml:space="preserve"> quòd uiſus ſentit
              <lb/>
            lucem & colores, qui ſunt in ſuperficie rei uiſę, ex forma extenſa, & ex luce, & colore, qui ſunt in ſu-
              <lb/>
            perficie rei uiſę per corpus diaphanũ, quod eſt medium inter uiſum & rem uiſam.</s>
            <s xml:id="echoid-s862" xml:space="preserve"> Et nihil compre-
              <lb/>
            hendit uiſus ex formis rerum uiſarum, niſi ex uerticationibus linearum extenſarũ inter rem uiſam
              <lb/>
            & centrum uiſus tantùm.</s>
            <s xml:id="echoid-s863" xml:space="preserve"> Et declaratum eſt, quòd hoc ſit poſsibile.</s>
            <s xml:id="echoid-s864" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div31" type="section" level="0" n="0">
          <head xml:id="echoid-head50" xml:space="preserve" style="it">21. Viſibile uiſui oppoſitum uidetur. 2 p 3.</head>
          <p>
            <s xml:id="echoid-s865" xml:space="preserve">NOs uerò modò exponemus quęſtionem, quare fiat uiſio ſecundum modum hunc, dicendo,
              <lb/>
            quòd uiſio nõ poteſt eſſe niſi ſecundum hunc modum.</s>
            <s xml:id="echoid-s866" xml:space="preserve"> Quoniam uiſus quando ſenſerit rem
              <lb/>
            uiſam, poſtquam non ſentiebat ipſam, aliquid accidit ei, quod nõ erat prius:</s>
            <s xml:id="echoid-s867" xml:space="preserve"> & nihil accidet,
              <lb/>
            poſt quam non erat prius, niſi per aliquam cauſam.</s>
            <s xml:id="echoid-s868" xml:space="preserve"> Et inuenimus, quòd uiſus quando fuerit oppoſi-
              <lb/>
            tus rei uiſæ, ſentiet ipſam, & cũ auferetur ab eius oppoſitione, non ſentiet ipſam, & cum reuertetur
              <lb/>
            ad oppoſititionem, reuertetur uiſus.</s>
            <s xml:id="echoid-s869" xml:space="preserve"> Et ſimiliter inuenimus, quando uiſus ſenſerit rem uiſam, dein-
              <lb/>
            de clauſerit palpebras, quòd ſenſus deſtruitur, & cum aperit palpebras, & res uiſa fuerit in oppoſi-
              <lb/>
            tione, reuertitur ſenſus.</s>
            <s xml:id="echoid-s870" xml:space="preserve"> Sed cauſſa eſt illud, quòd quando deſtruitur cauſſa, deſtruitur cauſſatum, &
              <lb/>
            quando reuertitur cauſſa, reuertitur cauſſatum.</s>
            <s xml:id="echoid-s871" xml:space="preserve"> Cauſſa ergo, quę facit contingere rem illam in uiſu,
              <lb/>
            eſt res uiſa, quando opponitur uiſui.</s>
            <s xml:id="echoid-s872" xml:space="preserve"> Viſus ergo non ſentit rem uiſam, niſi propter illud, quod facit
              <lb/>
            res uiſas contingere in uiſu, quando ſcilicet opponuntur uiſui.</s>
            <s xml:id="echoid-s873" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div32" type="section" level="0" n="0">
          <head xml:id="echoid-head51" xml:space="preserve" style="it">22. Viſibile per medium perſpicuum uidetur. 13 p 3.</head>
          <p>
            <s xml:id="echoid-s874" xml:space="preserve">ET iterum uiſus non comprehendit rem uiſam, niſi quando corpus, quod eſt medium inter ea,
              <lb/>
            fuerit diaphanũ.</s>
            <s xml:id="echoid-s875" xml:space="preserve"> Nam comprehenſio uiſus de re uiſa ex poſteriori aeris, qui eſt medius inter
              <lb/>
            eos, non eſt propter humiditatem aeris, ſed propter diaphanitatẽ eius.</s>
            <s xml:id="echoid-s876" xml:space="preserve"> Quoniam ſi medium
              <lb/>
            fuerit inter uiſum & rem uiſam aliquis lapis, aut aliud corpus diaphanũ quodcunq;</s>
            <s xml:id="echoid-s877" xml:space="preserve">: comprehendet
              <lb/>
            tunc uiſus rem uiſam, & erit comprehenſio ſecundum diaphanitatẽ corporis mediantis:</s>
            <s xml:id="echoid-s878" xml:space="preserve"> & quantò
              <lb/>
            corpus mediũ fuerit magis diaphanũ, tantò erit ſenſus uiſus de re illa manifeſtior.</s>
            <s xml:id="echoid-s879" xml:space="preserve"> Et ſimiliter quan
              <lb/>
            do fuerit inter uiſum & rem uiſam aqua clara diaphana, comprehendet uiſus rem uiſam à poſteriori
              <lb/>
            aquæ:</s>
            <s xml:id="echoid-s880" xml:space="preserve"> & ſi illa aqua fuerit tincta aliqua tinctura forti, ita ut deſtruatur diaphanitas, quamuis rema-
              <lb/>
            neat in ea humiditas, tunc uiſus non comprehendet illam rem uiſam, quæ eſt in aqua.</s>
            <s xml:id="echoid-s881" xml:space="preserve"> Declarabitur
              <lb/>
            ergo ex iſtis diſpoſitionibus, quòd uiſio non completur, niſi per diaphanitatem corporis medij, &
              <lb/>
            non per humiditatẽ.</s>
            <s xml:id="echoid-s882" xml:space="preserve"> Illud ergo quòd res uiſa operatur in uiſum apud ſuam oppoſitionẽ contra illũ,
              <lb/>
            ex quo eſt ſenſus, non cõpletur niſi per diaphanitatẽ corporis medij inter uiſum & rem uiſam.</s>
            <s xml:id="echoid-s883" xml:space="preserve"> Lux
              <lb/>
            ergo & color rei uiſæ non cõprehendetur à uiſu, niſi ex aliquo, quod ſit ex illa luce & colore in uiſu:</s>
            <s xml:id="echoid-s884" xml:space="preserve">
              <lb/>
            & illud non accidit ex luce & colore in uiſu, niſi quando corpus medium inter uiſum & rem uiſam
              <lb/>
            fuerit diaphanum.</s>
            <s xml:id="echoid-s885" xml:space="preserve"> Diaphanitas aũt non appropriatur alicui ex eis, quæ pendent ex luce & colore,
              <lb/>
            quo diuerſiſicetur à nõ diaphanitate, niſi quia forma lucis & coloris pertranſit per diaphanũ, & non
              <lb/>
            pertranſit per non diaphanũ:</s>
            <s xml:id="echoid-s886" xml:space="preserve"> & quia corpus diaphanum recipit formam lucis & coloris, & reddit
              <lb/>
            ipſam partibus oppoſitis luci & colori, corpus aũt nõ diaphanũ nõ habet iſtam proprietatẽ.</s>
            <s xml:id="echoid-s887" xml:space="preserve"> Et quia
              <lb/>
            uiſus non ſentit lucem & colorem, quæ ſuntin re uiſa, niſi ex aliquo cõtingente ex luce & colore in
              <lb/>
            uiſu, & illud non contingit in uiſu, niſi quando corpus medium inter uiſum & rem uiſam fuerit dia-
              <lb/>
            phanum:</s>
            <s xml:id="echoid-s888" xml:space="preserve"> & corpus diaphanum nulli appropriatur, quo diſtinguatur à corpore nõ diaphano ex eis,
              <lb/>
            </s>
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