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

List of thumbnails

< >
771
771 (469) 		772
772 (470)
773
773 (471) 		774
774 (472)
775
775 (473) 		776
776 (474)
777
777 		778
778
< >
page |< < (473) of 778 > >|
    <echo version="1.0RC">
      <text xml:lang="lat" type="free">
        <div xml:id="echoid-div1922" type="section" level="0" n="0">
          <p>
            <s xml:id="echoid-s52083" xml:space="preserve">
              <pb o="473" file="0775" n="775" rhead="LIBER DECIMVS."/>
            ciens diſſoluitur à radio ſolari, remota uerò nubes à uiſu nullam cauſſat reflexionem uel refractio-
              <lb/>
            nem ad uiſum, propter longitudinem diſtantię:</s>
            <s xml:id="echoid-s52084" xml:space="preserve"> quia ſi etiam à latere ſolis eſſet cõſiſtentia nubis ni-
              <lb/>
            mis alta, non accideret reflexionem luminis fieri ad uiſum:</s>
            <s xml:id="echoid-s52085" xml:space="preserve"> nec tunc apparerent pareliæ ipſis uiſi-
              <lb/>
            bus.</s>
            <s xml:id="echoid-s52086" xml:space="preserve"> Patet ergo propoſitum.</s>
            <s xml:id="echoid-s52087" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div1923" type="section" level="0" n="0">
          <head xml:id="echoid-head1411" xml:space="preserve" style="it">83. Ex cryſt allo hexagona ſoli oppoſita colores iridis generantur.</head>
          <p>
            <s xml:id="echoid-s52088" xml:space="preserve">Huiuſinodi enim colores generantur ex debilitatione luminis propter refractionem ad perpen
              <lb/>
            dicularem, ductam à centro corporis ſolis ad ſuperficiem unius parallelogrãmi ex lateribus cryſtal
              <lb/>
            li.</s>
            <s xml:id="echoid-s52089" xml:space="preserve"> Et quoniã (ut declarauimus in 27 th.</s>
            <s xml:id="echoid-s52090" xml:space="preserve">2 huius ſciẽtiæ) manifeſtũ eſt quòd à ſole illuminatur magis
              <lb/>
            me dietate cylindri ſibi oppoſiti, ſi rotun dus ſit cylindrus:</s>
            <s xml:id="echoid-s52091" xml:space="preserve"> hoc autem in cylin dro angulato eſſe non
              <lb/>
            poteſt (angulis ueniẽtibus in diametrũ corporis baſim per æqualia diuidentẽ) tunc enim ſola me-
              <lb/>
            dietas illuminatur propter radiorũ incidentiã, ut diximus ibidẽ.</s>
            <s xml:id="echoid-s52092" xml:space="preserve"> Sed ſi corpus illud columnare dia-
              <lb/>
            phanũ ſuerit:</s>
            <s xml:id="echoid-s52093" xml:space="preserve"> tunc alia medietas illius corporis illuminatur propter radiorum refractionẽ.</s>
            <s xml:id="echoid-s52094" xml:space="preserve"> Si itaq;</s>
            <s xml:id="echoid-s52095" xml:space="preserve">
              <lb/>
            ſuperficies corporis diaphani ſoli oppoſita unica fuerit, ut in corporibus quadrangulis:</s>
            <s xml:id="echoid-s52096" xml:space="preserve"> tunc una
              <lb/>
            fit luminis refractio fortis:</s>
            <s xml:id="echoid-s52097" xml:space="preserve"> & lumen ſub forma luminis tranſibit ad partem oppoſitam corporis, &
              <lb/>
            aggregabitur extra corpus ſub forma luminis:</s>
            <s xml:id="echoid-s52098" xml:space="preserve"> ſicut etiã hoc fortius euenit in corpore ſphærico dia
              <lb/>
            phano nõ cõcauo:</s>
            <s xml:id="echoid-s52099" xml:space="preserve"> eò quòd à ſuperficie maioris partis totius illius corporis ſphærici fit refractio ad
              <lb/>
            radiũ, qui perpendiculariter incidit ſuper ſuperficiem corpus ſphæricum contingentẽ, æquidiſtan
              <lb/>
            tem ſuperficiei ſecanti corpus ſolis per centrũ ſecundum aſpectũ, quo ab ipſo reſpicitur corpus illu
              <lb/>
            minandũ, ut oſten dimus in 48 huius.</s>
            <s xml:id="echoid-s52100" xml:space="preserve"> Ex tantorũ ergo & tot radiorũ aggregatione, & ſi nõ ad pun-
              <lb/>
            ctum unũ (quo niã hoc eſt impoſsibile propter diuerſitatẽ ſuperficierum incidentiæ) ad locũ tamẽ
              <lb/>
            naturalem paruũ fit luminis aggre gatio, ipſo lumine abſq;</s>
            <s xml:id="echoid-s52101" xml:space="preserve"> coloratione ſub forma luminis manẽte;</s>
            <s xml:id="echoid-s52102" xml:space="preserve">
              <lb/>
            & illud lumen aggregatũ calefacit corpus oppoſitũ, & incendit ex mora corpus inflãmabile ſubitò,
              <lb/>
            ut ſtupam uel aliud aliquid potentiã actiuã in ſe habentẽ ad inflam mationẽ.</s>
            <s xml:id="echoid-s52103" xml:space="preserve"> Si uerò corpus diapha-
              <lb/>
            num ſoli oppoſitũ ſit plurium ſuperficierũ ꝗ̃ unius planæ uel circularis, ſecundũ eam ſcilicet partẽ,
              <lb/>
            quæ ſoli opponitur:</s>
            <s xml:id="echoid-s52104" xml:space="preserve"> utpote ſi corpus quadrangulũ ſecundum unũ ſuorum angulorũ ſoli oppona-
              <lb/>
            tur:</s>
            <s xml:id="echoid-s52105" xml:space="preserve"> tunc fiet refractio radiorũ incidentium uni ſuperficiei ad ambas ſuքficies oppoſitas, & ſimiliter
              <lb/>
            radiorũ incidentium alteri ſuperficiei.</s>
            <s xml:id="echoid-s52106" xml:space="preserve"> Et cum ex parte oppoſita lumini refracto aer (qui eſt corpus
              <lb/>
            rarioris diaphani) occurrerit:</s>
            <s xml:id="echoid-s52107" xml:space="preserve"> refringentur radij ab utraq;</s>
            <s xml:id="echoid-s52108" xml:space="preserve"> ſuperficie ab illa perpendiculari, quæ ab
              <lb/>
            angulo ad angulũ ducta in corpore baſim ipſius per ęqualia duideret, uel alia ei æquidiſtante, & in
              <lb/>
            alio corpore denſo illi corpori diaphano ſubiecto, ut terra uel alio corpore quocunq;</s>
            <s xml:id="echoid-s52109" xml:space="preserve">: tunc quan-
              <lb/>
            doq;</s>
            <s xml:id="echoid-s52110" xml:space="preserve"> apparebunt duo lumina clara, aliquando uerò colorata:</s>
            <s xml:id="echoid-s52111" xml:space="preserve"> ut ſi corpus diaphanũ æqualium fue-
              <lb/>
            rit angulorũ & ſuperficierũ:</s>
            <s xml:id="echoid-s52112" xml:space="preserve"> & hoc patet experimentanti:</s>
            <s xml:id="echoid-s52113" xml:space="preserve"> eruntq́;</s>
            <s xml:id="echoid-s52114" xml:space="preserve"> tunc ibi duo colores confuſi, non
              <lb/>
            plures, color ſcilicet rubeus, & alius mixtus, quaſi uiridis, qui ſecundum cryſtalli uel alterius parui
              <lb/>
            corporis diſpoſitionẽ magis ſunt intenſi uel remiſsi.</s>
            <s xml:id="echoid-s52115" xml:space="preserve"> Quòd ſi ſuperficies corporis (quo ad partẽ ſoli,
              <lb/>
            oppoſitã) fuerint tres, ut ſunt in cryſtallo hexagona:</s>
            <s xml:id="echoid-s52116" xml:space="preserve"> tunc à qualibet ſuperficierũ oppoſitarum ſoli,
              <lb/>
            quæ ſunt tres, receptũ lumen cuiuslibet ſuperiorũ trium ſuperficierũ red ditur corpori oppoſito, ut
              <lb/>
            terrę uel alteri corpori cuicunq;</s>
            <s xml:id="echoid-s52117" xml:space="preserve">. Atq;</s>
            <s xml:id="echoid-s52118" xml:space="preserve"> horũ trium luminũ medium manet in ipſa perpen diculari co
              <lb/>
            lumnę cryſtallinæ baſim ſuam per æ qualia diuidente, uel ipſi diuidenti æ quidiſtante:</s>
            <s xml:id="echoid-s52119" xml:space="preserve"> & fit uiſibile
              <lb/>
            lumen illud, niſi lumẽ ſolis impediat:</s>
            <s xml:id="echoid-s52120" xml:space="preserve"> alia uerò duo refringuntur à dicta perpendiculari propter na-
              <lb/>
            turã ſecundi diaphani rarioris, ſcilicet aeris (dictũ enim eſt in 4 th.</s>
            <s xml:id="echoid-s52121" xml:space="preserve"> huius quòd medio ſecundi dia-
              <lb/>
            phani rariore exiſtente refractio ſit à perpendiculari) & eſt quaſi quædã diſperſio radiorũ.</s>
            <s xml:id="echoid-s52122" xml:space="preserve"> Apparẽt
              <lb/>
            aũt colores in iſtis luminibus ſic reflexis & refractis propter mixtionẽ nigredinis coloris cryſtalli-
              <lb/>
            ni cum lumine penetrante:</s>
            <s xml:id="echoid-s52123" xml:space="preserve"> & propter admixtiones umbrarum partium ipſius cryſtalli prominen-
              <lb/>
            tium ſecundũ acumen ſuorum angulorũ, quæ per 11 th.</s>
            <s xml:id="echoid-s52124" xml:space="preserve">2 huius proijciuntur ad partem oppoſitã in-
              <lb/>
            cidentiæ radiorũ in partem aduerſam corpori luminoſo:</s>
            <s xml:id="echoid-s52125" xml:space="preserve"> quarum umbrarum numerus facit diuer-
              <lb/>
            ſitatem colorum, quando lumini permiſcentur.</s>
            <s xml:id="echoid-s52126" xml:space="preserve"> Quoniam ubi radio luminis perpendiculari magis,
              <lb/>
            quo ad ſuperficiem incidentię (circa quã in uiciniori multorum radiorum fit aggregatio) color cry
              <lb/>
            ſtalli & umbræ cõmix us refle ctitur (quia ille radius magis eſt lumin oſus) tunc fit color rubeus.</s>
            <s xml:id="echoid-s52127" xml:space="preserve"> In
              <lb/>
            alijs uerò radijs ſecundum ſui debilitatẽ & coloris corporis & umbrarum plurium cõmixtionem
              <lb/>
            alij colores medij generantur.</s>
            <s xml:id="echoid-s52128" xml:space="preserve"> Fiunt aũt tres colores:</s>
            <s xml:id="echoid-s52129" xml:space="preserve"> quoniã ex tribus ſuperficie bus ſuperioribus
              <lb/>
            radij colliguntur ad quamlibet inferiorũ ſuperficierum:</s>
            <s xml:id="echoid-s52130" xml:space="preserve"> & color rubeus ſemper ab illa parte uide-
              <lb/>
            bitur, ubi radius perpendicularis ſuper ſuperficiem cryſtalli in contrario ſitu generatæ iridis oppo
              <lb/>
            ſitam ſoli aggregatis omnibus radijs, ſuæ ſuperficiei incidit, poſt refractionem factam ex aeris in-
              <lb/>
            terpoſiti diaphanitate.</s>
            <s xml:id="echoid-s52131" xml:space="preserve"> Et tunc quandoq;</s>
            <s xml:id="echoid-s52132" xml:space="preserve"> tres irides generantur, propter triplicem naturam refra-
              <lb/>
            ctionis in medio ſecundi diaphani rarioris, ut præmiſſum eſt:</s>
            <s xml:id="echoid-s52133" xml:space="preserve"> & quia ter tria ſaciũt quadratũ, qui eſt
              <lb/>
            9:</s>
            <s xml:id="echoid-s52134" xml:space="preserve"> erunt tunc 9 colorum indiuidua numero multiplicitatis trium ſuperficierum ſuperiorum, in nu-
              <lb/>
            merum trium in feriorum.</s>
            <s xml:id="echoid-s52135" xml:space="preserve"> Tres uerò erunt ſpecificæ differentiæ colorum:</s>
            <s xml:id="echoid-s52136" xml:space="preserve"> & fit iſtorum colorũ per
              <lb/>
            angulos corporis nulla ſenſibilis diſtinctro:</s>
            <s xml:id="echoid-s52137" xml:space="preserve"> quoniam & à linea angulorũ, quæ a ctu eſt indiuiſibilis,
              <lb/>
            reflexi uel refracti radij in diuiſibiles, nihil ſenſibile producunt.</s>
            <s xml:id="echoid-s52138" xml:space="preserve"> Non autem fiunt iſti colores iridis
              <lb/>
            per cryſtallam penitus per naturam colorum ueræ iridis, quorum diſtinctio formaliter eſt tantùm
              <lb/>
            in uiſu:</s>
            <s xml:id="echoid-s52139" xml:space="preserve"> ſed ſiunt per naturã lucis reflexæ à figura dicti corporis.</s>
            <s xml:id="echoid-s52140" xml:space="preserve"> unde etiam cauſſa ipſorum non eſt
              <lb/>
            ad uiſum facta reflexio:</s>
            <s xml:id="echoid-s52141" xml:space="preserve"> non enim uidentur per modum reflexionis, ſed per modum ſimplicis uiſio-
              <lb/>
            nis ut alia uiſibilia, quæ uiſui offerũtur, & à quolibet in eodẽ loco uidẽtur.</s>
            <s xml:id="echoid-s52142" xml:space="preserve"> Fit itaq;</s>
            <s xml:id="echoid-s52143" xml:space="preserve"> colorũ diftinctio
              <lb/>
            à figura corporis:</s>
            <s xml:id="echoid-s52144" xml:space="preserve"> quoniã à qualibet alia cryſtallo uel corpore peruio alterius figuræ colores uarij
              <lb/>
            </s>
          </p>
        </div>
      </text>
    </echo>
Impressum