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-s1974" xml:space="preserve">XXI. </s>
            <s xml:id="echoid-s1975" xml:space="preserve">Accedit tamen ei penitiùs aſtruendo etiam experientia quâ
              <lb/>
            nempe compertum habetur; </s>
            <s xml:id="echoid-s1976" xml:space="preserve">quòd objectum (velut A) in aquâ ſitum,
              <lb/>
            oculo (O) perpendiculariter imminenti, ità diſtans videtur (puta ad
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            Z) ut ſit perpetuò AZ quadrans ipſius AB, id quod ratiociniis præ-
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            cedentibus exquiſitè congruit. </s>
            <s xml:id="echoid-s1977" xml:space="preserve">Etenim cum experientia docuerit in
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            refractionibus ex aqua factis in aerem, _Sinum anguli Incidentia ad_
              <lb/>
            _Sinum anguli Refracti_ ſe habere circiter, ut 3 ad 4 ; </s>
            <s xml:id="echoid-s1978" xml:space="preserve">erit juxta conſtru-
              <lb/>
            ctionem præmiſſam ipſius ZB ad AB ratio ſubſeſquitertia; </s>
            <s xml:id="echoid-s1979" xml:space="preserve">ſeu hæc
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            ad illam ut 3 ad 4. </s>
            <s xml:id="echoid-s1980" xml:space="preserve">Quare nihil erat caaſæ cur hoc fretus experimento
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              <note position="right" xlink:label="note-0055-01" xlink:href="note-0055-01a" xml:space="preserve">_Iſ. Voſſ._</note>
            Præclariſſimus vir receptam de reſractione ſententiam impugnaret, & </s>
            <s xml:id="echoid-s1981" xml:space="preserve">
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            exploderet; </s>
            <s xml:id="echoid-s1982" xml:space="preserve">at potiùs ut ei promptiùs accederet, aut firmius adhæreret,
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            expoſiti Phænomeni cauſam adeò perſpicuam, adeo neceſſariam ſugge-
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            renti. </s>
            <s xml:id="echoid-s1983" xml:space="preserve">quinimo perpendicularem ipſam (quod adeò valde vult, acriterque
              <lb/>
            contendit) è ſuperiore doctrinâ quadantenus infringi, decurtaríque (ter-
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            minatione ſaltem refringi, tametſi non ſitu) patebit ad illam attendenti.</s>
            <s xml:id="echoid-s1984" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1985" xml:space="preserve">XXII Habetur itaque definitus imaginis ſitus, ob oculum in axe
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            collocatum. </s>
            <s xml:id="echoid-s1986" xml:space="preserve">Succedit ut idem præſtemus oculi gratiâ extra ipſum ubi-
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            cunque ſiti. </s>
            <s xml:id="echoid-s1987" xml:space="preserve">Sed priùs unum eſt quod opportunè moneamus, anteà
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            prætermiſſum; </s>
            <s xml:id="echoid-s1988" xml:space="preserve">eâdem ſcilicet operâ quoad radios convergentes ſimul
              <lb/>
            ac divergentes confici negotium. </s>
            <s xml:id="echoid-s1989" xml:space="preserve">Erunt enim ad punctum quodvis
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            (ceu A) tendentium radiorum refracti prorſus iidem eum illis, qui
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            divergentibus ab A convenient, modo cæteris manentibus invariatis
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            (refringente ſcilicet & </s>
            <s xml:id="echoid-s1990" xml:space="preserve">puncto A deſignatum ſitum retinentibus) me-
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            dia concipiantur tranſpoſita. </s>
            <s xml:id="echoid-s1991" xml:space="preserve">Nimirum, exempli cauſâ, ſi NK ſit
              <lb/>
            refractus radii BN verſus A tendentis è raro in denſum; </s>
            <s xml:id="echoid-s1992" xml:space="preserve">erit itidem
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            NH ipſi KN in directum poſitus radii AN B, è raro in denſum
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              <note position="right" xlink:label="note-0055-02" xlink:href="note-0055-02a" xml:space="preserve">Fig. 47.</note>
            (quæ nempe prioribus homogenea ſint) procedentis refractus. </s>
            <s xml:id="echoid-s1993" xml:space="preserve">Itaq;
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            </s>
            <s xml:id="echoid-s1994" xml:space="preserve">quæ de radiis divergentibus oſtenſa ſunt, ea convergentibus, adhibito
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            juſto moderamine, pariter adaptari poſſunt; </s>
            <s xml:id="echoid-s1995" xml:space="preserve">in horum locum diver-
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            gentes reſpectivè congruos ſubrogando. </s>
            <s xml:id="echoid-s1996" xml:space="preserve">Quare nedum in hoc caſu,
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            ſed in omnibus qui ſequentur, de radiis ſolummodò divergentibus in-
              <lb/>
            ſtituemus ſermonem; </s>
            <s xml:id="echoid-s1997" xml:space="preserve">eò ſubintelligentes etiam convergentes ex hac
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            regula determinabiles referri. </s>
            <s xml:id="echoid-s1998" xml:space="preserve">Quæ ſanè compendio deſerviens obſer-
              <lb/>
            vatio generalibus iſtis ſupra delibatis meruit intertexi; </s>
            <s xml:id="echoid-s1999" xml:space="preserve">nec enim ad
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            hanc ſolam quæ præ manibus, aſt ad omnes æquè, quaſlibet ad ſuper-
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            ficies, radiorum inflectiones ſe extendit.</s>
            <s xml:id="echoid-s2000" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s2001" xml:space="preserve">XXIII, Adſimilem & </s>
            <s xml:id="echoid-s2002" xml:space="preserve">indè conſequentem (cum paralleli à </s>
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