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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          <p>
            <s xml:id="echoid-s16582" xml:space="preserve">
              <pb o="233" file="0239" n="239" rhead="OPTICAE LIBER VII."/>
            mus has duas ſuperfluitates, & ponemus illas ſuper duas extremitates regulę, ita ut ponamus duas
              <lb/>
            extremitates ſuperfluitatum ſuper duas extremitates illius, quod remanſit de regula, & applicabi-
              <lb/>
            mus ſuperficiem extremitatum cum ſuperficie dorſi inſtrumenti:</s>
            <s xml:id="echoid-s16583" xml:space="preserve"> & erit illud, quod ponetur ex u-
              <lb/>
            traq;</s>
            <s xml:id="echoid-s16584" xml:space="preserve"> duarum ſuperfluitatum ſuper reſiduum regulæ æquale latitudini unius digiti.</s>
            <s xml:id="echoid-s16585" xml:space="preserve"> Hac autem po-
              <lb/>
            ſitione conſiderata eminebunt duæ ſuperfluitates ſuper duas extremitates regulę.</s>
            <s xml:id="echoid-s16586" xml:space="preserve"> Et ſi perforatum
              <lb/>
            fuerit illud, quod ſuperfluit de corpore in dorſo inſtrumenti, & immiſſus fuerit in foramen eius ſti-
              <lb/>
            lus ferreus, qui ipſum prohibeat exire, erit melius.</s>
            <s xml:id="echoid-s16587" xml:space="preserve"> Hoc autem perfecto, perfectum erit inſtrumen-
              <lb/>
            tum.</s>
            <s xml:id="echoid-s16588" xml:space="preserve"> Deinde accipiat experimentator regulam cupream paruæ latitudinis, cuius latitudo ſit dupla
              <lb/>
            diametri foraminis, quod eſt in ora inſtrumenti:</s>
            <s xml:id="echoid-s16589" xml:space="preserve"> & cuius ſpiſsitudo ſit æqualis diametro foraminis,
              <lb/>
            & cuius longitudo non ſit minor medietate cubiti:</s>
            <s xml:id="echoid-s16590" xml:space="preserve"> & uerificabitur regula iſta, donec fiat ualde re-
              <lb/>
            cta & uera:</s>
            <s xml:id="echoid-s16591" xml:space="preserve"> & fiant ſuperficies elus æquales & æquidiſtantes.</s>
            <s xml:id="echoid-s16592" xml:space="preserve"> Deinde obliquè ſecabimus altera par
              <lb/>
            te làtitudinem eius, quouſq;</s>
            <s xml:id="echoid-s16593" xml:space="preserve"> finis longitudinis eius contineat cum fine latitudinis eius angulum a-
              <lb/>
            cutum, ut poſsit ſic facilius declinare & mouere eam quocunq;</s>
            <s xml:id="echoid-s16594" xml:space="preserve"> quis uoluerit:</s>
            <s xml:id="echoid-s16595" xml:space="preserve"> & ponet latitudinem
              <lb/>
            eius ex alia extremitate perpendicularem ſuper finem longitudinis eius.</s>
            <s xml:id="echoid-s16596" xml:space="preserve"> Deinde diuidemus hanc
              <lb/>
            latitudinem in duo æqualia, & extrahemus ex loco diuiſionis lineam in ſuperficie faciei regulæ,
              <lb/>
            quæ extendatur in longitudine eius, & erit perpendicularis ſuper latitudinem eius.</s>
            <s xml:id="echoid-s16597" xml:space="preserve"> Cum ergo hæc
              <lb/>
            regula fuerit ſuperpoſita ſuperficiei laminæ, erit ſuperficies eius ſuperior in ſuperficie circuli me-
              <lb/>
            dij trium circulorum figuratorum in interiore ora inſtrumenti.</s>
            <s xml:id="echoid-s16598" xml:space="preserve"> Nam ſpiſsitudo huius regulæ eſt æ-
              <lb/>
            qualis diametro foraminis, & diameter foraminis eſt æqualis perpendiculari exeunti è centro fo-
              <lb/>
            raminis, quod eſt in ora inſtrumenti ad ſuperficiem laminæ:</s>
            <s xml:id="echoid-s16599" xml:space="preserve"> quia diameter foraminis eſt æqua-
              <lb/>
            lis duabus lineis trium linearum paruarum, quæ diſtinctæ ſunt de linea perpendiculari in interio-
              <lb/>
            re ora inſtrumenti.</s>
            <s xml:id="echoid-s16600" xml:space="preserve"> Cum ergo hæc regula fuerit erecta ſuper oram ipſius, & fuerit ſuperficies latitu-
              <lb/>
            dinis eius ſuper ſuperficiem laminę:</s>
            <s xml:id="echoid-s16601" xml:space="preserve"> tunc linea deſcripta in medio eius, erit in ſuperficie medij cir-
              <lb/>
            culi prædicti:</s>
            <s xml:id="echoid-s16602" xml:space="preserve"> quia perpendicularis, quę egreditur à quolibet puncto huius lineę ad finem longitu-
              <lb/>
            dinis regulę, eſt æqualis perpendiculari, quę egreditur à centro foraminis ad ſuperficiem laminę:</s>
            <s xml:id="echoid-s16603" xml:space="preserve">
              <lb/>
            nam utraq;</s>
            <s xml:id="echoid-s16604" xml:space="preserve"> iſtarum perpendicularium eſt æqualis diametro foraminis.</s>
            <s xml:id="echoid-s16605" xml:space="preserve"/>
          </p>
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        <div xml:id="echoid-div554" type="section" level="0" n="0">
          <head xml:id="echoid-head482" xml:space="preserve" style="it">3. Radius medio denſiori perpendicularis, irrefract{us} penetrat. 42. p 2. Idem 17 n 1.</head>
          <p>
            <s xml:id="echoid-s16606" xml:space="preserve">CVm ergo experimentator uoluerit experiri tranſitum luminis in aqua per hoc inſtrumen-
              <lb/>
            tum:</s>
            <s xml:id="echoid-s16607" xml:space="preserve"> accipiet uas rectarum orarum, ut cadum cupreum, aut ollam figulinam, aut conſimile:</s>
            <s xml:id="echoid-s16608" xml:space="preserve">
              <lb/>
            & ſit altitudo orarum eius non minor medietate cubiti:</s>
            <s xml:id="echoid-s16609" xml:space="preserve"> & ſit diameter circumferentię eius
              <lb/>
            non minor diametro inſtrumenti:</s>
            <s xml:id="echoid-s16610" xml:space="preserve"> & adæquentur orę eius, donec ſuperficies, quę tranſit per oras
              <lb/>
            eius, ſit ſuperficies æqualis:</s>
            <s xml:id="echoid-s16611" xml:space="preserve"> & ponamus in fundo eius corpus diuerſarum partium aut diuerſorum
              <lb/>
            colorum, ut annulum, aut argentum depictum, aut depingatur in fundo eius pictura manifeſta:</s>
            <s xml:id="echoid-s16612" xml:space="preserve"> de-
              <lb/>
            inde infundatur aqua clara in uas, donec impleatur:</s>
            <s xml:id="echoid-s16613" xml:space="preserve"> & expectetur donec motus eius quieſcat.</s>
            <s xml:id="echoid-s16614" xml:space="preserve"> Cum
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            ergo motus eius quieuerit, erigatur aſpiciens, aut ſedeat erectus, & aſpiciat ad uas, & apponat ui-
              <lb/>
            ſum ſuum corpori, quod eſt in fundo aquę, aut picturę, quę eſt in fundo aquę, donec linea inter ui-
              <lb/>
            ſum & medium illius corporis aut picturę illius, ſit perpendicularis ſuper ſuperficiem aquę quò ad
              <lb/>
            ſenſum, & aſpiciat corpus, quod eſt in fundo, aut picturam:</s>
            <s xml:id="echoid-s16615" xml:space="preserve"> tunc inueniet illam eo modo, quo eſt, &
              <lb/>
            inueniet ordinationem ſuarum partium inter ſe eo modo, quo ordinarentur, ſi aſpiceret illud, cum
              <lb/>
            uas eſſet uacuum.</s>
            <s xml:id="echoid-s16616" xml:space="preserve"> Hoc autem declarato, certificatur, quòd illud, quod comprehenditur in fundo a-
              <lb/>
            quæ, cum aſpexerit illud eadem poſitione, qua aſpexit corpus, quòd eſt in fundo aquæ, aut pictu-
              <lb/>
            ram:</s>
            <s xml:id="echoid-s16617" xml:space="preserve"> comprehenditur ſecundum ordinationem ſuarum partium.</s>
            <s xml:id="echoid-s16618" xml:space="preserve"> Hoc autem certificato, ſi quis uo-
              <lb/>
            luerit experiri tranſitum lucis:</s>
            <s xml:id="echoid-s16619" xml:space="preserve"> eligat locum, ſuper quem oritur lux ſolis, in quo ponat uas, & obſer-
              <lb/>
            uet, ut ſuperficies circumferentię uaſis ſit æquidiſtans horizonti:</s>
            <s xml:id="echoid-s16620" xml:space="preserve"> hoc autem poteſt obſeruari hoc
              <lb/>
            modo:</s>
            <s xml:id="echoid-s16621" xml:space="preserve"> ut ſit circumferentia ſuperficiei aquę æquidiſtans circumferentię uaſis:</s>
            <s xml:id="echoid-s16622" xml:space="preserve"> & ſi intus in uaſè
              <lb/>
            prope circumferentiam eius fuerit ſignatus circulus, æquidiſtans circumferentię uaſis, erit melius
              <lb/>
            ad hoc, ut circumferentia ſuperficiei aquę comparetur ad circumferentiam circuli.</s>
            <s xml:id="echoid-s16623" xml:space="preserve"> Deinde expe-
              <lb/>
            rimentator debet imponere inſtrumentum rotundum intra hoc uas, ita ut duę regulę paruę po-
              <lb/>
            ſitæ ſuper duo extrema regulæ maioris, ſuperponantur oræ uaſis ex utraque parte:</s>
            <s xml:id="echoid-s16624" xml:space="preserve"> tunc medietas
              <lb/>
            inſtrumenti, & regula extenſa in longitudine inſtrumenti erunt intra uas:</s>
            <s xml:id="echoid-s16625" xml:space="preserve"> deinde addatur aqua, aut
              <lb/>
            diminuatur de ea, donec fiat ſuperficies aquę una cum centro inſtrumenti:</s>
            <s xml:id="echoid-s16626" xml:space="preserve"> & ſit aqua clara:</s>
            <s xml:id="echoid-s16627" xml:space="preserve"> deinde
              <lb/>
            reuoluatur inſtrumentum in circuitu uaſis, donec obumbretur illud, quod eſt intra aquam ex oris
              <lb/>
            eius:</s>
            <s xml:id="echoid-s16628" xml:space="preserve"> tunc teneatur regula altera manu, & reuoluatur reliqua manu inſtrumentum ſuper ſe in cir-
              <lb/>
            cuitu centri eius, donec foramen, quod eſt in ora inſtrumenti, ſit oppoſitum corpori ſolis, & tran-
              <lb/>
            ſeat lumen ſolis per foramen oræ inſtrumenti, & perueniat ad alterum foramen tabulę paruæ, &
              <lb/>
            tranſeat per illud.</s>
            <s xml:id="echoid-s16629" xml:space="preserve"> Cum ergo pertranſierit forma lucis per duo foramina, perueniet ad fundum a-
              <lb/>
            quæ:</s>
            <s xml:id="echoid-s16630" xml:space="preserve"> tunc experimentator obſeruabit, ut ſitus lucis in regula de ſecundo foramine, ſit ſitus æqua-
              <lb/>
            lis:</s>
            <s xml:id="echoid-s16631" xml:space="preserve"> hoc autem ſitu præſeruato, & luce perueniente ad ſuperficiem aquæ, auferat experimentator
              <lb/>
            manus ſuas ab inſtrumento, & ſtet uel ſedeat erectus, & inſpiciat ad fundum aquæ, ex quarta, cu-
              <lb/>
            ius oræ ſunt abſciſſę, & ſeruet poſitionem, quam ſeruauerat, cum aſpexerat corpus, quod erat in
              <lb/>
            fundo aquæ, ut ſit certus, quòd illud, quod uidet, eſt, ſecundum quod eſt:</s>
            <s xml:id="echoid-s16632" xml:space="preserve"> tunc ergo cum intue-
              <lb/>
            bitur illud, quod eſt intra aquam de ora inſtrumenti:</s>
            <s xml:id="echoid-s16633" xml:space="preserve"> inueniet lumen pertranſiens ex duobus fo-
              <lb/>
            </s>
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