Barrow, Isaac, Lectiones opticae & geometricae : in quibus phaenomenon opticorum genuinae rationes investigantur, ac exponuntur: et generalia curvarum linearum symptomata declarantur

Table of contents

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[11.] Lect. III.
[12.] _Corol_. 1. Ang. _a_ BG. ang. _a_ BP > ang. δ BH. ang. δ BP. 2. Ang. _a_ BG. ang. PBG > ang. δ BH. PBH.
[13.] Lect. IV.
[14.] Lect.V.
[15.] Lect. VI.
[16.] Lect. VI I.
[17.] Lect. VIII.
[18.] Lect. IX.
[19.] Lect. X.
[20.] Lect. XIV.
[21.] Lect. XV.
[22.] APPENDICVLA.
[23.] Lect. XVI.
[24.] Lect. XVII.
[25.] Lect. XVIII.
[26.] ERRATA.
[27.] Benevolo Lectori.
[28.] Lectio I.
[29.] Lect. II.
[30.] Lect. III.
[31.] Lect. IV.
[32.] Lect. VII.
[33.] Lect. VIII.
[34.] Lect. IX.
[35.] Lect. X.
[36.] Exemp. I.
[37.] _Exemp_. II.
[38.] _Exemp_. III
[39.] Exemp. IV.
[40.] Eæemp. V.
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            ſuo æſtimanda, ad vitæ communis uſum beneſicia ſubminiſtret; </s>
            <s xml:id="echoid-s210" xml:space="preserve">visûs
              <lb/>
            imperfectionibus & </s>
            <s xml:id="echoid-s211" xml:space="preserve">vitiis tam prompta, quàm certa, minimi ſumptûs,
              <lb/>
            & </s>
            <s xml:id="echoid-s212" xml:space="preserve">nullius periculi remedia conferendo. </s>
            <s xml:id="echoid-s213" xml:space="preserve">Neque, quum curioſiſſimus
              <lb/>
            iſte ſenſus noſter ità varias indies, ità miras rerum ſpecies exhibeat
              <lb/>
            nobis; </s>
            <s xml:id="echoid-s214" xml:space="preserve">non admodum oblectare nos, non eximiâ voluptate mentes
              <lb/>
            noſtras afficere poſſit, unde talis emergat apparentiarum diverſitas, & </s>
            <s xml:id="echoid-s215" xml:space="preserve">
              <lb/>
            quis ſit illas attingendi modus nedum accuratè, certóque cognoſcere,
              <lb/>
            ſed utcunque veriſimilitér arbitrari; </s>
            <s xml:id="echoid-s216" xml:space="preserve">præſertim quum in nullâ parte
              <lb/>
            noſtri, nec in tota fortaſſis rerum compage, neceſſitatibus, commo-
              <lb/>
            dis, & </s>
            <s xml:id="echoid-s217" xml:space="preserve">voluptatibus noſtris proſpicientis melioris naturæ ſeu fines
              <lb/>
            agendi, ſeu modos pleniùs queamus perſpicere; </s>
            <s xml:id="echoid-s218" xml:space="preserve">nuſquam adeò di-
              <lb/>
            ftinctiùs aut apertiùs opificis _πανσφδ_ eluceat artificium. </s>
            <s xml:id="echoid-s219" xml:space="preserve">Verùm
              <lb/>
            elogia pertexere non vacat, aut convenit nobis. </s>
            <s xml:id="echoid-s220" xml:space="preserve">Rem potiùs ipſam
              <lb/>
            aggrediamur.</s>
            <s xml:id="echoid-s221" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s222" xml:space="preserve">III. </s>
            <s xml:id="echoid-s223" xml:space="preserve">Quæ circa viſum occupatur diſcipiina communiter in tria mem-
              <lb/>
            bra diſpertitur; </s>
            <s xml:id="echoid-s224" xml:space="preserve">primum, quod viſus directis radiis objecta cernentis
              <lb/>
            affectiones conſiderat (hoc ſpeciatim Optice nominatur;) </s>
            <s xml:id="echoid-s225" xml:space="preserve">alterum,
              <lb/>
            quod è radiorum ab opacis corporibus repercuſſu oriundas ſpeculatur
              <lb/>
            apparentias (cui Catoptricæ nomen inditum;) </s>
            <s xml:id="echoid-s226" xml:space="preserve">tertium denique, quod
              <lb/>
            ideò Dioptrica vocitatur, quia cauſas inveſtigat, aut exponit eorum
              <lb/>
            quæ à radiis apparent per diverſa media tranſlucentibus, & </s>
            <s xml:id="echoid-s227" xml:space="preserve">eorum oc-
              <lb/>
            curſu demutatis Quam diſtributionem ut non improbamus, ità nobis
              <lb/>
            haud obſervandam proponimus; </s>
            <s xml:id="echoid-s228" xml:space="preserve">nedum quia multa pariter his com-
              <lb/>
            munia ſunt, at præcipuè quia viſio quævis, ut libet ſimplex ac directa,
              <lb/>
            ſicuti reverà non abſque nonnulla radiorum inflectione peragitur, ità
              <lb/>
            nec eâ ſeclusâ penitus intelligi poteſt aut explicari. </s>
            <s xml:id="echoid-s229" xml:space="preserve">Igitur hujuſmodi
              <lb/>
            methodo potiùs inſiſtendum cenſemus; </s>
            <s xml:id="echoid-s230" xml:space="preserve">ut nempe primò viſionis cau-
              <lb/>
            ſas (quæ ſcilicet illam extrinſecus eſſiciunt, aut afficiunt) examine-
              <lb/>
            mus; </s>
            <s xml:id="echoid-s231" xml:space="preserve">tum ut videndi modum (hoc eſt quo pacto ſenſus hic noſter ido-
              <lb/>
            neis organis inſtructus iſtis concurrentibus cauſis, objectorum illas,
              <lb/>
            quas experimur, differentias apprehendit) adnitamur exponere; </s>
            <s xml:id="echoid-s232" xml:space="preserve">de-
              <lb/>
            hinc, ut Phænomena quædam ſelectiora ſuſcipiamus elucidanda;
              <lb/>
            </s>
            <s xml:id="echoid-s233" xml:space="preserve">poſtremóque forſan, ut de viſùs remediis ac ſubſidiis aliquid ſub-
              <lb/>
            jungamus.</s>
            <s xml:id="echoid-s234" xml:space="preserve"/>
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          <p>
            <s xml:id="echoid-s235" xml:space="preserve">IV. </s>
            <s xml:id="echoid-s236" xml:space="preserve">Viſionis cauſas externas quod attinet, nemini jam dubium eſt,
              <lb/>
            exiſtimo, non ullâ (quanquam _Empedocli, Platoui, Enclidi_, veteribus
              <lb/>
            aliisid placitum erat) ab oculo radiorum emiſſione, verùm ab objectis
              <lb/>
            defluente re quâpiam, oculoſque percellente viſum effici; </s>
            <s xml:id="echoid-s237" xml:space="preserve">quod &</s>
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