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

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            <emph style="sc">Lect.</emph>
          XVI.</head>
          <p>
            <s xml:id="echoid-s7358" xml:space="preserve">I. </s>
            <s xml:id="echoid-s7359" xml:space="preserve">P_Unctorum ex inflectione determinatis apparentibus locis,_ con-
              <lb/>
            quieſcere poſſem; </s>
            <s xml:id="echoid-s7360" xml:space="preserve">ſiquidem exinde magnitudinum apparentiæ
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            deducuntur, quotlibet in ipſis exiſtentium punctorum imagines de-
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            ſignando. </s>
            <s xml:id="echoid-s7361" xml:space="preserve">cæterùm nè juſto parciùs in hac parte, vel illiberaliùs egiſſe
              <lb/>
            videar, etiam _de rectarum linearum (conſequenter & </s>
            <s xml:id="echoid-s7362" xml:space="preserve">planarum ſuper-_
              <lb/>
            _ficierum, quibus diſtinctè viſui repræſentandis natur a præcipuè conſu-_
              <lb/>
            _luiſſe videtur) apparentiis & </s>
            <s xml:id="echoid-s7363" xml:space="preserve">imaginibus expreſſiora ſpecimina quædam_
              <lb/>
            _haud gravabor adnectere._ </s>
            <s xml:id="echoid-s7364" xml:space="preserve">de quibus etiam circa reliquarum magnitu-
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            dinum apparentias propius ac promptius fiat judicium.</s>
            <s xml:id="echoid-s7365" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s7366" xml:space="preserve">II. </s>
            <s xml:id="echoid-s7367" xml:space="preserve">Notetur autem imprimìs; </s>
            <s xml:id="echoid-s7368" xml:space="preserve">Sicuti (quod ſæpiùs in antedictis
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            habetur inſinuatum) cujuſque puncti quodammodò duplex eſt imago;
              <lb/>
            </s>
            <s xml:id="echoid-s7369" xml:space="preserve">una ſimplex, abſoluta, principalis; </s>
            <s xml:id="echoid-s7370" xml:space="preserve">illa ſcilicet, quæ in recta verſatur
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            ad ſuperficiem inflectentem perpendiculari, perque radians punctum
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            ſimul ac oculi centrum tranſeunte (hoc eſt in communi lucidæ radia-
              <lb/>
            tionis, ſuperficiei reflectentis, ipſiúſque viſionis axe) altera verò
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            relata, mutabilis, ac minùs præcipua; </s>
            <s xml:id="echoid-s7371" xml:space="preserve">quæ talis eſt reſpectu oculi
              <lb/>
            extra rectam inflectenti ſuperficiei perpendicularem arbitrariè conſti-
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            tuti; </s>
            <s xml:id="echoid-s7372" xml:space="preserve">ità pari fermè modo duplex cujuſque magnitudinis imago con-
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            cipi poteſt; </s>
            <s xml:id="echoid-s7373" xml:space="preserve">una quidem abſoluta (quam ſaltem hoc nomine deſig-
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            nabo) quæ ex punctorum ſingulorum in ipſa exiſtentium abſolutis
              <lb/>
            imaginibus quaſi conflatur, illas ſaltem comprehendit (qualis in ob-
              <lb/>
            jecta congrua ſuperficie vividè deformaretur; </s>
            <s xml:id="echoid-s7374" xml:space="preserve">qualíſque videretur
              <lb/>
            oculo ad infinitam ab inflectente ſuperficie diſtantiam ritè collocato)
              <lb/>
            altera verò relata, quæ oculum reſpicit ubivis in certa poſitione con-
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            ſtitutum; </s>
            <s xml:id="echoid-s7375" xml:space="preserve">quid velim, & </s>
            <s xml:id="echoid-s7376" xml:space="preserve">quare ſic diſtinguam ab exemplis benè mul-
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            tis in decurſu proponendis luculenter apparebit.</s>
            <s xml:id="echoid-s7377" xml:space="preserve"/>
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