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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        <div xml:id="echoid-div232" type="section" level="0" n="0">
          <p>
            <s xml:id="echoid-s6630" xml:space="preserve">
              <pb o="113" file="0119" n="119" rhead="OPTICAE LIBER IIII."/>
            hanc perpendicularẽ:</s>
            <s xml:id="echoid-s6631" xml:space="preserve"> & ſi penetraret motus ultra punctum, in quod cadit, ut liberũ inueniret tranſi
              <lb/>
            tum:</s>
            <s xml:id="echoid-s6632" xml:space="preserve"> caderet quidem hæclinea inter perpendicularem, tranſeuntem per politum, & lineam ſuperfi-
              <lb/>
            ciei orthogonalem ſuper perpendicularem, & obſeruaret menſuram ſitus, reſpectu perpendicularis
              <lb/>
            tranſeuntis, & reſpectu lineæ alterius, quæ orthogonalis eſt ſuper perpen dicularem illam.</s>
            <s xml:id="echoid-s6633" xml:space="preserve"> Compa-
              <lb/>
            cta eſt enim menſura ſitus huius motus ex ſitu ad perpendicularem & ſitu ad orthogonalem.</s>
            <s xml:id="echoid-s6634" xml:space="preserve"> Re-
              <lb/>
            pulſio uerò per perpendicularem incedens, cum no poſsit repellere motum ſecundum menſuram,
              <lb/>
            quam habet ad perpen dicularem tranſeuntem per politum:</s>
            <s xml:id="echoid-s6635" xml:space="preserve"> quia nec modicum intrat:</s>
            <s xml:id="echoid-s6636" xml:space="preserve"> repellit ergo
              <lb/>
            ſecundum menſuram ſitus ad perpendicularem, quam habet ad orthogonalem.</s>
            <s xml:id="echoid-s6637" xml:space="preserve"> Et quando motus
              <lb/>
            regreſsio eadem fuerit menſura ſitus ad orthogonalem, quæ fuit prius ad eandem ex alia parte:</s>
            <s xml:id="echoid-s6638" xml:space="preserve"> erit
              <lb/>
            ſimiliter ei eadem menſura ſitus ad perpendicularem tranſeuntem, quę fuit prius.</s>
            <s xml:id="echoid-s6639" xml:space="preserve"> Sed ponderoſum
              <lb/>
            corpus in regreſſu, cum finitur repulſionis motus, ex natura ſua deſcendit, & ad centrũ tendit.</s>
            <s xml:id="echoid-s6640" xml:space="preserve"> Lux
              <lb/>
            autem eandem habens reflectendi naturam, cum ei naturale non ſit aſcendere aut deſcendere, mo-
              <lb/>
            uetur in reflexione ſecundum lineam incœptam uſq;</s>
            <s xml:id="echoid-s6641" xml:space="preserve"> ad obſtaculum, quod ſiſtere faciat motum.</s>
            <s xml:id="echoid-s6642" xml:space="preserve"> Et
              <lb/>
            hæc eſt cauſſa reflexionis.</s>
            <s xml:id="echoid-s6643" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div233" type="section" level="0" n="0">
          <head xml:id="echoid-head264" xml:space="preserve" style="it">19. Colorem luci permiſtum reflecti, reflexionis organo ostenditur. 3 p 5.</head>
          <p>
            <s xml:id="echoid-s6644" xml:space="preserve">PAtet etiam ex ſuperioribus, quòd colores ſimul mouentur cum lucibus:</s>
            <s xml:id="echoid-s6645" xml:space="preserve"> unde erit reflexio co-
              <lb/>
            loris, ſicut & lucis.</s>
            <s xml:id="echoid-s6646" xml:space="preserve"> Et ſi probationẽ eius uidere uolueris ſecundum modum in parte ſecunda
              <lb/>
            aſsignatũ, poteris:</s>
            <s xml:id="echoid-s6647" xml:space="preserve"> Verùm per inſtrumentũ ad hanc denotandam reflexionẽ factum, nõ plenè
              <lb/>
            uidebis propter debilitatẽ coloris.</s>
            <s xml:id="echoid-s6648" xml:space="preserve"> Debilitatur enim color per elongationẽ:</s>
            <s xml:id="echoid-s6649" xml:space="preserve"> per reflexionẽ:</s>
            <s xml:id="echoid-s6650" xml:space="preserve"> per fora
              <lb/>
            men, per quod intrat.</s>
            <s xml:id="echoid-s6651" xml:space="preserve"> Quòd aũt foramen debilitet, planũ per hoc:</s>
            <s xml:id="echoid-s6652" xml:space="preserve"> Quia lux apparet maior poſt fora
              <lb/>
            men magnũ, quàm poſt paruũ.</s>
            <s xml:id="echoid-s6653" xml:space="preserve"> Pari modo cũ foramina ſtricta ſunt:</s>
            <s xml:id="echoid-s6654" xml:space="preserve"> color poſt reflexionẽ aut nullus
              <lb/>
            apparebit, aut ualde modicus.</s>
            <s xml:id="echoid-s6655" xml:space="preserve"> Tamen ſi in prædicto inſtrumento uidere uolueris:</s>
            <s xml:id="echoid-s6656" xml:space="preserve"> facias ſpeculũ ar-
              <lb/>
            genteum:</s>
            <s xml:id="echoid-s6657" xml:space="preserve"> in ferreo enim ſpeculo color apparet debilior:</s>
            <s xml:id="echoid-s6658" xml:space="preserve"> quoniã in reflexione miſcetur cum luce re-
              <lb/>
            flexa, mixta exluce deſcendente & luce ſpeculi ferrei modica, & color ferreus colori reflexo mixtus
              <lb/>
            debilitat ipſum.</s>
            <s xml:id="echoid-s6659" xml:space="preserve"> Verùm in domo unici foraminis tantùm, habeatur inſtrumentũ prædictum, cui do
              <lb/>
            mui paries opponatur albus;</s>
            <s xml:id="echoid-s6660" xml:space="preserve"> & inſtrumentũ foramini domus aptetur:</s>
            <s xml:id="echoid-s6661" xml:space="preserve"> cuius foraminis latitudo ſit,
              <lb/>
            ut duo inſtrumenti foramina occupare poſsit, per quorũ alterũ inſpiciatur paries albus, domui op-
              <lb/>
            poſitus, & parti comprehenſæ parietis apponatur corpus coloris fortis, & per aliud inſtrumenti fo-
              <lb/>
            ramen uideatur pars parietis.</s>
            <s xml:id="echoid-s6662" xml:space="preserve"> Cum ergo lux intrauerit per foramina inſtrumẽti:</s>
            <s xml:id="echoid-s6663" xml:space="preserve"> uidebitur color re-
              <lb/>
            flecti per foramen illud reſpiciẽs, quod oppoſitum eſt colorato corpori, per aliud minimè:</s>
            <s xml:id="echoid-s6664" xml:space="preserve"> & ita ac-
              <lb/>
            cidet quocunq;</s>
            <s xml:id="echoid-s6665" xml:space="preserve"> oppoſito corpori foramine.</s>
            <s xml:id="echoid-s6666" xml:space="preserve"> Et quæ dicta ſunt in reflexione lucis, conſiderari po-
              <lb/>
            terunt in reflexione coloris.</s>
            <s xml:id="echoid-s6667" xml:space="preserve"> Occupauit autem latitudo foraminis parietis duo inſtrumenti fora-
              <lb/>
            mina ei adhibita, ut maior deſcendat in ſpeculum lux, & melius appareat color reflexus.</s>
            <s xml:id="echoid-s6668" xml:space="preserve"> Et quoniã
              <lb/>
            color debilitatur per foramen directus, & ſimiliter reflexus, cum in corpus ceciderit uiſui oppoſitũ,
              <lb/>
            percipietur ſecundus:</s>
            <s xml:id="echoid-s6669" xml:space="preserve"> unde ſi poſt reflexionem cadat in corpus album foramini colorationis adhi-
              <lb/>
            bitum:</s>
            <s xml:id="echoid-s6670" xml:space="preserve"> forſan propter debilitatem non comprehendet eum uiſus:</s>
            <s xml:id="echoid-s6671" xml:space="preserve"> adhibito autem ſecundo uiſu fo-
              <lb/>
            ramini colorationis, forſan comprehendetur:</s>
            <s xml:id="echoid-s6672" xml:space="preserve"> quoniam primus, non ſecundus uidebitur.</s>
            <s xml:id="echoid-s6673" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div234" type="section" level="0" n="0">
          <head xml:id="echoid-head265" xml:space="preserve">QVOÒ
            <unsure/>
          D COMPREHENSIO FORMARVM È
            <unsure/>
          CORPORIBVS
            <lb/>
          politis fiat reflexione. Cap. 1111.</head>
          <head xml:id="echoid-head266" xml:space="preserve" style="it">20. Falſa eſt utra opinio: & radios à uiſu ad ſpeculum miſſos, inde́ ad uiſibile reflexos, ima
            <lb/>
          ginem percipere: & imaginẽ in ſpeculo iam antè impreſſam inde ad uiſum manare. 23. 24 p 5.</head>
          <p>
            <s xml:id="echoid-s6674" xml:space="preserve">SVper modum cõprehenſionis formæ in politis corporibus diſſentiunt plurimi.</s>
            <s xml:id="echoid-s6675" xml:space="preserve"> Vnde quidam
              <lb/>
            eorum radios à uiſu exire ad ſpeculũ, & à ſpeculo redire, & formã rei in reditu comprehendere
              <lb/>
            exiſtimant:</s>
            <s xml:id="echoid-s6676" xml:space="preserve"> alij affirmant formã corporis ſpeculo ei oppoſito imprimi:</s>
            <s xml:id="echoid-s6677" xml:space="preserve"> & proin de in eo uideri,
              <lb/>
            ſicut in corporibus fit cõprehenſio formarũ naturalium eius.</s>
            <s xml:id="echoid-s6678" xml:space="preserve"> Verùm quòd aliter ſit, palàm per hoc.</s>
            <s xml:id="echoid-s6679" xml:space="preserve">
              <lb/>
            Quoniã ſi quis ſe uiderit in aliqua ſpeculi parte, motus in partẽ aliam, non uidebit ſe in parte prima,
              <lb/>
            ſed in ſecunda:</s>
            <s xml:id="echoid-s6680" xml:space="preserve"> quod non accideret, ſi in parte prima infixa eſſet eius forma:</s>
            <s xml:id="echoid-s6681" xml:space="preserve"> pari modo ſi ad tertiam
              <lb/>
            mutetur partem, mutabitur locus apparentiæ formæ, nec apparebit in prima uel in ſecunda parte.</s>
            <s xml:id="echoid-s6682" xml:space="preserve">
              <lb/>
            Amplius:</s>
            <s xml:id="echoid-s6683" xml:space="preserve">uiſo corpore aliquo, & uidente ab eo ſitu remoto:</s>
            <s xml:id="echoid-s6684" xml:space="preserve"> poterit accidere, ut non uideat corpus
              <lb/>
            illud in ſpeculo illo, licet uideat totam ſpeculi ſuperficiem:</s>
            <s xml:id="echoid-s6685" xml:space="preserve"> quod quidem non eſſet, ſi imprimeretur
              <lb/>
            forma in ſpeculo, cum uideatur ſpeculum, & non mutet locum, & corpus ſimiliter ſit immotum, &
              <lb/>
            forma eius inficiat ſpeculum, ſicut & prius.</s>
            <s xml:id="echoid-s6686" xml:space="preserve"> Et ut planè appareat, non accidere hoc ex comprehen-
              <lb/>
            ſione formæ:</s>
            <s xml:id="echoid-s6687" xml:space="preserve"> obturetur medietas foraminum inſtrumenti, & in aliquo obturatorum ſit ſcriptura
              <lb/>
            aliqua, ſi inſpiciatur ſpeculum regulæ per foramen ſcripturã reſpiciens:</s>
            <s xml:id="echoid-s6688" xml:space="preserve"> comprehendet
              <gap/>
            r in ſpecu-
              <lb/>
            lo ſcriptura:</s>
            <s xml:id="echoid-s6689" xml:space="preserve"> per quodcũq;</s>
            <s xml:id="echoid-s6690" xml:space="preserve"> aliud minimè:</s>
            <s xml:id="echoid-s6691" xml:space="preserve"> quod ſi ſcripturæ forma ſpeculo eſſet impreſſa, per quod-
              <lb/>
            cunq;</s>
            <s xml:id="echoid-s6692" xml:space="preserve"> foramẽ inſtrumẽti poſſet percipi.</s>
            <s xml:id="echoid-s6693" xml:space="preserve"> Simili modo in ſpeculis columnaribus perforamen, reſpi-
              <lb/>
            ciens tantùm foramẽ obturatũ, in quo eſt ſcriptura, cõprehendetur ſcripturę ſitus.</s>
            <s xml:id="echoid-s6694" xml:space="preserve"> Verùm in ſpecu-
              <lb/>
            lis pyramidalibus & ſphæricis ſitus & magnitudo ſcripturæ mutabitur.</s>
            <s xml:id="echoid-s6695" xml:space="preserve"> Amplius:</s>
            <s xml:id="echoid-s6696" xml:space="preserve"> ſpeculo columna
              <lb/>
            ri extracto, regula ſuper baſes ſuas directè ſita apparebit facies hominis in eo directa.</s>
            <s xml:id="echoid-s6697" xml:space="preserve"> Si uerò eriga-
              <lb/>
            tur regula, aut multum inclinetur, uidebitur diſtorta.</s>
            <s xml:id="echoid-s6698" xml:space="preserve"> Palàm ergo, quòd non accidit comprehen-
              <lb/>
            ſio ex forma fixa in ſpeculo, cum non comprehendatur res uiſa in ſpeculis, niſi fuerit uiſus in ſitu re-
              <lb/>
            </s>
          </p>
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