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

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            <s xml:id="echoid-s7052" xml:space="preserve">
              <pb o="105" file="0123" n="123" rhead=""/>
            id quadantenus hoc modo pertentantes attingetis. </s>
            <s xml:id="echoid-s7053" xml:space="preserve">Oculi centrum
              <lb/>
            (quale dari paſſim ſupponitur, ei ſaltem analogum quid dari videtur;
              <lb/>
            </s>
            <s xml:id="echoid-s7054" xml:space="preserve">nec indè, quoad illam quæ præ manibus rem, erroris quicquam
              <lb/>
            proveniet) oculi centrum, inquam, ubicunque pro libitu conſtitu-
              <lb/>
            tum ceu punctum radians concipiatur; </s>
            <s xml:id="echoid-s7055" xml:space="preserve">tum ex eo duo prodeuntes
              <lb/>
            radii ad propoſitam ſuperficiem (eo quem hujus exigit natura vel pro-
              <lb/>
            prietas ſpecialis modo) inflectantur. </s>
            <s xml:id="echoid-s7056" xml:space="preserve">tum inter hos inflexos colloca-
              <lb/>
            tum intelligatur objectum; </s>
            <s xml:id="echoid-s7057" xml:space="preserve">ejus certè ſpecies inter duos primos ab
              <lb/>
            oculi centro procedentes radios conſiſtet, quæ cum ipſo (quoad ap-
              <lb/>
            parentem anguli quantitatem, punctorum correſpondentium poſitionem,
              <lb/>
            & </s>
            <s xml:id="echoid-s7058" xml:space="preserve">reliquas affectiones) objecto comparata voti compotes vos reddet; </s>
            <s xml:id="echoid-s7059" xml:space="preserve">
              <lb/>
            & </s>
            <s xml:id="echoid-s7060" xml:space="preserve">id quidem perfectius, ſi extremorum ac mediorum præſertim
              <lb/>
            objecti punctorum juſtas imagines, ex doctrina hactenus tradita,
              <lb/>
            velitis inveſtigare. </s>
            <s xml:id="echoid-s7061" xml:space="preserve">ab appoſitis exemplis res manifeſtior evadet; </s>
            <s xml:id="echoid-s7062" xml:space="preserve">in
              <lb/>
            quibus notetur punctum O ſemper oculi centrum, rectam OBA ra-
              <lb/>
            diationis axem (ſuperficiebus inflectentibus perpendicularem, & </s>
            <s xml:id="echoid-s7063" xml:space="preserve">objecta
              <lb/>
            in partes æ quales dirimentem) denotare.</s>
            <s xml:id="echoid-s7064" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s7065" xml:space="preserve">_Exemp. </s>
            <s xml:id="echoid-s7066" xml:space="preserve">1. </s>
            <s xml:id="echoid-s7067" xml:space="preserve">Proponatur Superficies plana medii refringentis den-_
              <lb/>
              <note position="right" xlink:label="note-0123-01" xlink:href="note-0123-01a" xml:space="preserve">Fig. 169.</note>
            _ſioris (aquæ ſi placet, aut vitri) objectum continentis,_ veluti Super-
              <lb/>
            ficies a recta MN repræſentata. </s>
            <s xml:id="echoid-s7068" xml:space="preserve">& </s>
            <s xml:id="echoid-s7069" xml:space="preserve">ab oculi centro O prodeant utcun-
              <lb/>
            que duo radii OM, ON; </s>
            <s xml:id="echoid-s7070" xml:space="preserve">qui in MF, NG refringantur; </s>
            <s xml:id="echoid-s7071" xml:space="preserve">inter
              <lb/>
            hos jam deſignetur objectum FAG (ab axe OA biſectum) hujus è
              <lb/>
            medio FGMN ſpectati ſpecies (vel apparentia) alicubi conſiſtet
              <lb/>
            inter rectas OM, ON, veluti puta ad φαγ. </s>
            <s xml:id="echoid-s7072" xml:space="preserve">cùm autem (ut ex hu-
              <lb/>
            juſce ſuperficiei natura, communíque refractionum lege palàm eſt)
              <lb/>
            ſit angulus φ O γ major angulo FOG; </s>
            <s xml:id="echoid-s7073" xml:space="preserve">hæc objecti ſpeciem ampli-
              <lb/>
            ficat inflectio. </s>
            <s xml:id="echoid-s7074" xml:space="preserve">item cùm puncta (ſibi reſpondentia) F, φ; </s>
            <s xml:id="echoid-s7075" xml:space="preserve">& </s>
            <s xml:id="echoid-s7076" xml:space="preserve">G, γ ad
              <lb/>
            eaſdem reſpectivè partes jaceant, ab eadem objecti poſito non immu-
              <lb/>
            tatur. </s>
            <s xml:id="echoid-s7077" xml:space="preserve">quòd ſi punctorum φ, α, γ poſitio juxta ſuperiorem doctrinam
              <lb/>
            ſtrictiùs exquiratur, de totiu
              <emph style="sub">s</emph>
            imaginis φαγ figurâ diſtantiâque
              <lb/>
            ſatìs accuratum feretur judicium.</s>
            <s xml:id="echoid-s7078" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s7079" xml:space="preserve">_Exemp. </s>
            <s xml:id="echoid-s7080" xml:space="preserve">II. </s>
            <s xml:id="echoid-s7081" xml:space="preserve">Proponatur corpus denſum_ PMNQ, _Superficiebus_
              <lb/>
              <note position="right" xlink:label="note-0123-02" xlink:href="note-0123-02a" xml:space="preserve">Fig. 170.</note>
            _planis parallelis_ (MN, PQ) _comprehenſum;_ </s>
            <s xml:id="echoid-s7082" xml:space="preserve">& </s>
            <s xml:id="echoid-s7083" xml:space="preserve">ab oculi centro O
              <lb/>
            prodeuntes radii OM, ON ad ſuperficiem MN refringantur in MP,
              <lb/>
            NQ; </s>
            <s xml:id="echoid-s7084" xml:space="preserve">horum verò ad Superficiem PQ refracti ſint PF, QG (qui,
              <lb/>
            propter incidentias (ad M, P, & </s>
            <s xml:id="echoid-s7085" xml:space="preserve">N, Q) pares, ipſis OM, ON
              <lb/>
            æquidiſtabunt) inter PF, QG ſtatuatur objectum FAG, cujus ſit
              <lb/>
            imago φ α γ; </s>
            <s xml:id="echoid-s7086" xml:space="preserve">tum verò manifeſtum eſt hìc ſe rem ſimiliter habere ac
              <lb/>
            in Exemplo præcedenti.</s>
            <s xml:id="echoid-s7087" xml:space="preserve"/>
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