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-s4731" xml:space="preserve">
              <pb o="74" file="0092" n="92" rhead=""/>
            CB exiſtet; </s>
            <s xml:id="echoid-s4732" xml:space="preserve">ſin AE &</s>
            <s xml:id="echoid-s4733" xml:space="preserve">lt; </s>
            <s xml:id="echoid-s4734" xml:space="preserve">AN, punctum Z verſus π exiſtet; </s>
            <s xml:id="echoid-s4735" xml:space="preserve">ſin
              <lb/>
            AE = AN; </s>
            <s xml:id="echoid-s4736" xml:space="preserve">concurſus infinitè diſtabit; </s>
            <s xml:id="echoid-s4737" xml:space="preserve">ſeu proximus reflexus ipſi
              <lb/>
            N π parallelus erit.</s>
            <s xml:id="echoid-s4738" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s4739" xml:space="preserve">Not. </s>
            <s xml:id="echoid-s4740" xml:space="preserve">ductâ AQ ad CB perpendiculari, ſi AE = AN; </s>
            <s xml:id="echoid-s4741" xml:space="preserve">erit
              <lb/>
            AN = √{AQ q/3}. </s>
            <s xml:id="echoid-s4742" xml:space="preserve">Nam AQ q = AP x AN = 3 AN x AN = 3 AN x AN
              <lb/>
            = 3 ANq; </s>
            <s xml:id="echoid-s4743" xml:space="preserve">itaque punctum N, iſtos caſus diſterminans, facilè de-
              <lb/>
              <note position="left" xlink:label="note-0092-01" xlink:href="note-0092-01a" xml:space="preserve">Fig. 106.</note>
            ſignatur.</s>
            <s xml:id="echoid-s4744" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s4745" xml:space="preserve">Rationem ipſi tantillùm attendentes perſpicietis; </s>
            <s xml:id="echoid-s4746" xml:space="preserve">mihi ſanè cunctas
              <lb/>
            evolvendo minutias non animi ſatìs, non otii ſuppetit.</s>
            <s xml:id="echoid-s4747" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s4748" xml:space="preserve">XXVIII. </s>
            <s xml:id="echoid-s4749" xml:space="preserve">Juvabit his unam, loco forſan opportuniore prætermiſſam,
              <lb/>
            obſervatiunculam attexere. </s>
            <s xml:id="echoid-s4750" xml:space="preserve">Si fuerit Z radiantis A lmago, viciſſim erit
              <lb/>
            A radiantis Z lmago. </s>
            <s xml:id="echoid-s4751" xml:space="preserve">è dictis quoad ſpeciales caſus facilè cernitur
              <lb/>
            hoc conſectari. </s>
            <s xml:id="echoid-s4752" xml:space="preserve">quin & </s>
            <s xml:id="echoid-s4753" xml:space="preserve">hinc generatim verum apparebit ſatìs: </s>
            <s xml:id="echoid-s4754" xml:space="preserve">Si fue-
              <lb/>
            rit Z ipſius A imago, tantum unus idcircò ab A manantium inflexus
              <lb/>
            per Z tranſibit. </s>
            <s xml:id="echoid-s4755" xml:space="preserve">(hoc imagini proprium eſſe ſæpiùs in decurſu in-
              <lb/>
            culcata ſatìs arguunt, ſuperque) quare reciprocè ſolus unus ab Z
              <lb/>
            manantium inflexus per A tranlibit (nam ſi duo tales per A tranſire
              <lb/>
            dicantur, etiam indè duo per Z tranſibunt, contra hypotheſin) erit
              <lb/>
            igitur A ipſius Z imago. </s>
            <s xml:id="echoid-s4756" xml:space="preserve">Merebatur hæc (compendio bene ſerviens,
              <lb/>
            & </s>
            <s xml:id="echoid-s4757" xml:space="preserve">caſus inter ſe varios conferentibus affundens lucem) obſervatio gene-
              <lb/>
            ralibus intertexi; </s>
            <s xml:id="echoid-s4758" xml:space="preserve">niſi quòd non omnia ſe nobis ſtatim produnt; </s>
            <s xml:id="echoid-s4759" xml:space="preserve">& </s>
            <s xml:id="echoid-s4760" xml:space="preserve">
              <lb/>
            quædam in abſtractione ſumma non ità facilè vèl explicari poſſunt,
              <lb/>
            vel comprobari.</s>
            <s xml:id="echoid-s4761" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s4762" xml:space="preserve">A Catoptricis jam aliquando manum. </s>
            <s xml:id="echoid-s4763" xml:space="preserve">quæ contentus ità quadante-
              <lb/>
            nus promoviſſe, haud diſparia (certè magìs nova, miniméque pro-
              <lb/>
            trita) circa refractiones ſphæricas, ſeu circulares, attentabo.</s>
            <s xml:id="echoid-s4764" xml:space="preserve"/>
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