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

< >
281
281 (275) 		282
282 (276)
283
283 (277) 		284
284 (278)
285
285 (279) 		286
286 (280)
287
287 (281) 		288
288 (282)
289
289 (283) 		290
290 (284)
< >
page |< < (278) of 778 > >|
    <echo version="1.0RC">
      <text xml:lang="lat" type="free">
        <div xml:id="echoid-div625" type="section" level="0" n="0">
          <head xml:id="echoid-head535" xml:space="preserve" style="it">
            <pb o="278" file="0284" n="284" rhead="ALHAZEN"/>
          fractiuum poſitum fuerint in eadem recta linea: imago uidebitur duplicata. 44 p 10.</head>
          <p>
            <s xml:id="echoid-s19297" xml:space="preserve">SIuerò b g z d fuerit in corpore columnari, & corpus fuerit groſsius aere:</s>
            <s xml:id="echoid-s19298" xml:space="preserve"> tunc form a k o uidebi
              <lb/>
            tur apud arcum g p & apud arcum ſibi æqualem, & ſibi reſpondentem exarcu b d:</s>
            <s xml:id="echoid-s19299" xml:space="preserve"> Sed hæc for
              <lb/>
            ma non erit circularis:</s>
            <s xml:id="echoid-s19300" xml:space="preserve"> quia figura a h p g cum fuerit circumuoluta circa a k:</s>
            <s xml:id="echoid-s19301" xml:space="preserve"> nõ tranſibit per li-
              <lb/>
            neam illam arcus g p per totam ſuperficiem columnarem:</s>
            <s xml:id="echoid-s19302" xml:space="preserve"> Sed refringetur fortè forma ex aliquibus
              <lb/>
            portionibus columnaribus, & erit continua in una parte & ſimiliter in alia.</s>
            <s xml:id="echoid-s19303" xml:space="preserve"> Nam ſuperficies ex l k,
              <lb/>
            quæ etiam tranſit per axem columnæ, facit in ſuperficie columnę, quę eſt ex parte a, lineam rectam,
              <lb/>
            quæ tranſit per b, & extenditur in longitudine columnæ:</s>
            <s xml:id="echoid-s19304" xml:space="preserve"> & non refringitur forma k o ex illa linea
              <lb/>
            recta:</s>
            <s xml:id="echoid-s19305" xml:space="preserve"> nam k b erit perpendicularis ſuper illam lineam rectam.</s>
            <s xml:id="echoid-s19306" xml:space="preserve"> Non ergo erit forma rotunda, ſi fue-
              <lb/>
            rit corpus columnare:</s>
            <s xml:id="echoid-s19307" xml:space="preserve"> ſed erunt duæ formæ, quarum altera refringitur ſuper alteram.</s>
            <s xml:id="echoid-s19308" xml:space="preserve"> Videbitur
              <lb/>
            ergo k o eſſe duo, quorum utrumq;</s>
            <s xml:id="echoid-s19309" xml:space="preserve"> erit maius k o:</s>
            <s xml:id="echoid-s19310" xml:space="preserve"> & forma utriuſque erit diuerſa à forma k o:</s>
            <s xml:id="echoid-s19311" xml:space="preserve"> & ta-
              <lb/>
            men illæ duæ formæ erunt apud idem punctum, ſcilicet centrum uiſus.</s>
            <s xml:id="echoid-s19312" xml:space="preserve"> In uiſibilibus autem aſſue-
              <lb/>
            tis nihil eſt, quod comprehendatur à uiſu ultra diaphanum corpus, ſphæricum, groſsius aere, cu-
              <lb/>
            ius concauum ſit ex parte uiſus.</s>
            <s xml:id="echoid-s19313" xml:space="preserve"> Nam ſi fuerit ex uitro aut aliquo lapide:</s>
            <s xml:id="echoid-s19314" xml:space="preserve"> oportet, ut ſit portio ſphæ-
              <lb/>
            ræ concaua, & ut res uiſa ſit intra illam ſphæram, aut ut ſuperficies eius, quæ eſt ultra concauitatem,
              <lb/>
            ſit plana, & res uiſa adhæreat illi.</s>
            <s xml:id="echoid-s19315" xml:space="preserve"> Et illi duo ſitus non inueniuntur, aut rarò:</s>
            <s xml:id="echoid-s19316" xml:space="preserve"> non ergo ſolicitemur
              <lb/>
            circa huiuſmodi.</s>
            <s xml:id="echoid-s19317" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div626" type="section" level="0" n="0">
          <head xml:id="echoid-head536" xml:space="preserve" style="it">51. Stella in horizonte ut plurimum uidetur maior, quàm in medio cæli. 54 p 10.</head>
          <p>
            <s xml:id="echoid-s19318" xml:space="preserve">ITem:</s>
            <s xml:id="echoid-s19319" xml:space="preserve"> non inuenitur aliquod corpus ſubtilius aere, cuius ſuperficies, quæ eſt ex parte uiſus, ſit
              <lb/>
            plana aut conuexa.</s>
            <s xml:id="echoid-s19320" xml:space="preserve"> Et nõ inuenitur aliquid ſubtilius aere, ultra quod comprehendatur aliquid,
              <lb/>
            niſi corpus cœli & ignis.</s>
            <s xml:id="echoid-s19321" xml:space="preserve"> Et non diuiditur à corpore aeris ſuperficies, quæ diſtinguit unam par-
              <lb/>
            tem ab alia, ſed quanto magis appropinquat aer cœlo, tantò magis purificatur, donec fiat ignis.</s>
            <s xml:id="echoid-s19322" xml:space="preserve">
              <lb/>
            Subtilitas ergo eius fit ordinatè ſecundum ſucceſsionem, non in differentia terminata.</s>
            <s xml:id="echoid-s19323" xml:space="preserve"> Formę ergo
              <lb/>
            eorum, quæ ſunt in cœlo, quando extenduntur ad uiſum, non refringuntur apud concauitatẽ ſphæ-
              <lb/>
            ræignis, cum non ſit ibi ſuperficies concaua determinata.</s>
            <s xml:id="echoid-s19324" xml:space="preserve"> Nullum ergo inuenitur corpus ſubtilius
              <lb/>
            aere, in quo extendantur formæ uiſibilium, & refringantur apud ſuperficiem eius, niſi corpus cœle
              <lb/>
            ſte:</s>
            <s xml:id="echoid-s19325" xml:space="preserve"> & corpus cœleſte eſt ſphęricum concauum ex parte uiſus.</s>
            <s xml:id="echoid-s19326" xml:space="preserve"> Ergo omnes ſtellæ, quæ ſunt in cœlo,
              <lb/>
            extendũtur in corpore cœli, & refringuntur apud cõcauitatẽ cœli, & extenduntur ιn corpore ignis,
              <lb/>
            & in corpore aeris rectè, donec perueniant ad uiſum.</s>
            <s xml:id="echoid-s19327" xml:space="preserve"> Et centrum concauitatis cœli eſt centrum ter-
              <lb/>
            ræ.</s>
            <s xml:id="echoid-s19328" xml:space="preserve"> Dico ergo quòd ſtellæ in maiore parte comprehenduntur in ſuis locis:</s>
            <s xml:id="echoid-s19329" xml:space="preserve"> & quòd ſemper compre-
              <lb/>
            henduntur non in ſuis magnitudinibus:</s>
            <s xml:id="echoid-s19330" xml:space="preserve"> & cum hoc diuerſatur magnitudo uniuſcuiuſq;</s>
            <s xml:id="echoid-s19331" xml:space="preserve"> earum, ſe-
              <lb/>
            cundum locorum diuerſitatem.</s>
            <s xml:id="echoid-s19332" xml:space="preserve"> Diuerſitas autem locorum eſt propter radiorum refractorum po-
              <lb/>
            ſitionem, ut prius diximus.</s>
            <s xml:id="echoid-s19333" xml:space="preserve"> Diuerſitas autem quantitatum eſt propter remotionem:</s>
            <s xml:id="echoid-s19334" xml:space="preserve"> nam propter
              <lb/>
            remotionem comprehenduntur minores, quàm ſint in ueritate, ut diximus in tertio tractatu, ſcili-
              <lb/>
            cet quòd illa, quæ in maxima remotione ſunt, comprehenduntur minora.</s>
            <s xml:id="echoid-s19335" xml:space="preserve"> Diuerſitas autem quanti
              <lb/>
            tatum ſecundum diuerſitatem locorum, accidit propter refractionem, cuius cauſſam hic declaraui-
              <lb/>
            mus:</s>
            <s xml:id="echoid-s19336" xml:space="preserve"> & in quarto capitulo [15 n] declarauimus, quòd formæ ſtellarum, quæ comprehenduntur à ui-
              <lb/>
            ſu, ſunt refractæ.</s>
            <s xml:id="echoid-s19337" xml:space="preserve"> Dico ergo, quòd omnis ſtella comprehenditur ex omnibus locis cœli, per quos
              <lb/>
            mouetur, minore quantitate, quàm ſit in ueritate, ſecundum quod exigit remotio eius, (ſcilicet mi-
              <lb/>
            nor, ſi uiſa fuerit rectè) cum nõ fuerit inter illam & uiſum aliqua nubes, aut uapor groſſus.</s>
            <s xml:id="echoid-s19338" xml:space="preserve"> Et omnis
              <lb/>
            ſtella in uertice capitis aſpicientis exiſtens uidetur minor, quàm in alio loco cœli:</s>
            <s xml:id="echoid-s19339" xml:space="preserve"> & quantò magis
              <lb/>
            remouetur à uertice capitis, tantò magis apparet maior:</s>
            <s xml:id="echoid-s19340" xml:space="preserve"> ita ut in horizonte appareat maior, quàm
              <lb/>
            in alio loco.</s>
            <s xml:id="echoid-s19341" xml:space="preserve"> Et hoc eſt commune omnibus ſtellis remotis & propinquis.</s>
            <s xml:id="echoid-s19342" xml:space="preserve"> Item ſi in aere fuerit uapor
              <lb/>
            groſſus, ultra quem ſuerit aliqua ſtella:</s>
            <s xml:id="echoid-s19343" xml:space="preserve"> tunc comprehendetur maior, quàm ſi eſſet ſine illo uapore:</s>
            <s xml:id="echoid-s19344" xml:space="preserve">
              <lb/>
            & multoties accidit, ut uapor groſſus ſit in horizonte.</s>
            <s xml:id="echoid-s19345" xml:space="preserve"> Vnde ſtellæ in maiore parte uidentur in hori-
              <lb/>
            zonte maiores, quàm in medio cœli.</s>
            <s xml:id="echoid-s19346" xml:space="preserve"> Et hoc apparet in diſtantijs, quæ ſunt inter illas, magis, quàm
              <lb/>
            In magnitudinibus ipſarum ſtellarum:</s>
            <s xml:id="echoid-s19347" xml:space="preserve"> nam quantitas ſtellæ, quò ad uiſum, eſt parua, ſed exceſſus in
              <lb/>
            diuerſitate diſtantiæ inter ſtellas, cum fuerint in horizonte, eſt grandis & manifeſtus ſenſui, & maxi
              <lb/>
            mè in diſtantijs ſpatioſis, & maximè, ſi in horizonte fuerit uapor groſſus.</s>
            <s xml:id="echoid-s19348" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div627" type="section" level="0" n="0">
          <head xml:id="echoid-head537" xml:space="preserve" style="it">52. Diameter ſtellæ uertici propinquæ, & duarum inter ſe diſtantia, refractè uiſa, minor:
            <lb/>
          rectè, maior uidetur. 51 p 10.</head>
          <p>
            <s xml:id="echoid-s19349" xml:space="preserve">SIt ergo circulus meridiei in aliquo horizonte, b k:</s>
            <s xml:id="echoid-s19350" xml:space="preserve"> & differentia communis inter hunc circu-
              <lb/>
            lum & concauitatem cœli, circulus m e z:</s>
            <s xml:id="echoid-s19351" xml:space="preserve"> & ſit centrum mundi g:</s>
            <s xml:id="echoid-s19352" xml:space="preserve"> & centrum uiſus t:</s>
            <s xml:id="echoid-s19353" xml:space="preserve"> & extra-
              <lb/>
            hamus g t in partem t:</s>
            <s xml:id="echoid-s19354" xml:space="preserve"> & occurrat circulo meridiei in b:</s>
            <s xml:id="echoid-s19355" xml:space="preserve"> & ſecet circulum, qui eſt in concauitate
              <lb/>
            orbis, in e:</s>
            <s xml:id="echoid-s19356" xml:space="preserve"> erit ergo b uertex capitis, quò ad uiſum t.</s>
            <s xml:id="echoid-s19357" xml:space="preserve"> Sit k l diameter alicuius ſtellæ, aut diſtantia
              <lb/>
            inter aliquas duas ſtellas:</s>
            <s xml:id="echoid-s19358" xml:space="preserve"> & linea t b tranſeat per medium k l, & ſecet illam in c:</s>
            <s xml:id="echoid-s19359" xml:space="preserve"> ergo erit arcus k b
              <lb/>
            æqualis arcui b l:</s>
            <s xml:id="echoid-s19360" xml:space="preserve"> [Nam quia t b bifariam ſecans k l ex theſi ſecat ad angulos rectos per 3 p 3:</s>
            <s xml:id="echoid-s19361" xml:space="preserve"> con-
              <lb/>
            nexæ igitur rectæ k b, b l æquabuntur per 4 p 1.</s>
            <s xml:id="echoid-s19362" xml:space="preserve"> Quare per 28 p 3 peripheria k b æquatur periphe-
              <lb/>
            riæ b l] & continuemus duas lineas t k, t l:</s>
            <s xml:id="echoid-s19363" xml:space="preserve"> erit ergo angulus k t l ille, à quo t comprehendit k l, ſi ré-
              <lb/>
            ctè comprehenderet:</s>
            <s xml:id="echoid-s19364" xml:space="preserve"> & refringatur k ad t ex m, & l ad t ex z:</s>
            <s xml:id="echoid-s19365" xml:space="preserve"> & continuemus g m, g z:</s>
            <s xml:id="echoid-s19366" xml:space="preserve"> & pertranſeant
              <lb/>
            ad f, o:</s>
            <s xml:id="echoid-s19367" xml:space="preserve"> & cõtinuemus lineas k m, m t, l z, z t.</s>
            <s xml:id="echoid-s19368" xml:space="preserve"> Forma, aũt quę extenditur ex k per m k, refringitur ք m t:</s>
            <s xml:id="echoid-s19369" xml:space="preserve">
              <lb/>
            </s>
          </p>
        </div>
      </text>
    </echo>
Impressum