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-s4765" xml:space="preserve">I. </s>
            <s xml:id="echoid-s4766" xml:space="preserve">_CAtoptricâ circulari defunctus ad Dioptricam promovemur;_
              <lb/>
            </s>
            <s xml:id="echoid-s4767" xml:space="preserve">quorſum incidentium quotcunque refractis unâ ſimulo perâ
              <lb/>
            delineandis, adeóque reſractionum ſymptomatis organicè pertentan-
              <lb/>
            dis modum imprimìs exponemus, præ cæteris, opinor expeditum. </s>
            <s xml:id="echoid-s4768" xml:space="preserve">
              <lb/>
            Seorſim ad v γ æqualem diametro (NG) circuli refringentis deſcri-
              <lb/>
            batur circulus v π γ. </s>
            <s xml:id="echoid-s4769" xml:space="preserve">item habeat v γ ad S γ rationem illam, quæ re-
              <lb/>
            fractiones determinat (illam autem deinceps, ut antehac, conſtanter
              <lb/>
            nuncupabo rationem I ad R) & </s>
            <s xml:id="echoid-s4770" xml:space="preserve">ſuper diametro S γ deſcribatur quo-
              <lb/>
            que circulus SH γ. </s>
            <s xml:id="echoid-s4771" xml:space="preserve">Incidat jam radius quilibet MN P, cui con-
              <lb/>
              <note position="right" xlink:label="note-0093-01" xlink:href="note-0093-01a" xml:space="preserve">Fig. 107.
                <lb/>
              108.</note>
            veniens deſignandus eſt refractus. </s>
            <s xml:id="echoid-s4772" xml:space="preserve">ut hoc aſlequamur, circulo adpoſi-
              <lb/>
            to à V adaptetur v π = NP; </s>
            <s xml:id="echoid-s4773" xml:space="preserve">& </s>
            <s xml:id="echoid-s4774" xml:space="preserve">centro γ per π deſcriptus circulus
              <lb/>
            ſecet circulum SH γ in H; </s>
            <s xml:id="echoid-s4775" xml:space="preserve">connexáque γ Hcirculum v π γ interſecet
              <lb/>
            in ξ. </s>
            <s xml:id="echoid-s4776" xml:space="preserve">demùm connexâ v ξ, circulo NPGaccommodetur NX =
              <lb/>
            v ξ; </s>
            <s xml:id="echoid-s4777" xml:space="preserve">erit NX ipſius NP refractus. </s>
            <s xml:id="echoid-s4778" xml:space="preserve">Etenim (ductis GP, GX) eſt
              <lb/>
            γ H. </s>
            <s xml:id="echoid-s4779" xml:space="preserve">γ ξ :</s>
            <s xml:id="echoid-s4780" xml:space="preserve">: (γ S γ v :</s>
            <s xml:id="echoid-s4781" xml:space="preserve">:) I. </s>
            <s xml:id="echoid-s4782" xml:space="preserve">R. </s>
            <s xml:id="echoid-s4783" xml:space="preserve">hoc eſt γ π. </s>
            <s xml:id="echoid-s4784" xml:space="preserve">γ ξ:</s>
            <s xml:id="echoid-s4785" xml:space="preserve">:I. </s>
            <s xml:id="echoid-s4786" xml:space="preserve">R. </s>
            <s xml:id="echoid-s4787" xml:space="preserve">hoc eſt
              <lb/>
            GP. </s>
            <s xml:id="echoid-s4788" xml:space="preserve">GX:</s>
            <s xml:id="echoid-s4789" xml:space="preserve">: I. </s>
            <s xml:id="echoid-s4790" xml:space="preserve">R. </s>
            <s xml:id="echoid-s4791" xml:space="preserve">cùm itaque ſint ipſæ GP, GX recti ſinus angulo-
              <lb/>
            rum GN π, GNX(quorum GNPeſt angulus incidentiæ) liquet
              <lb/>
            propoſitum.</s>
            <s xml:id="echoid-s4792" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s4793" xml:space="preserve">II. </s>
            <s xml:id="echoid-s4794" xml:space="preserve">Ad ipſa _Symptomata_ progrediamur exponenda radiis ad circu-
              <lb/>
            lum refractis competentia; </s>
            <s xml:id="echoid-s4795" xml:space="preserve">quorum illa pro more primò pertractabi-
              <lb/>
              <note position="right" xlink:label="note-0093-02" xlink:href="note-0093-02a" xml:space="preserve">Fig. 109.</note>
            mus, quæ radianti puncto conveniunt ad infinitam quaſi diſtantiam
              <lb/>
            poſito, ſeu parallelos ad ſenſum radios ejaculanti. </s>
            <s xml:id="echoid-s4796" xml:space="preserve">Quocirca per
              <lb/>
            circuli refringentis Centrum C punctúmque de longinquo radians
              <lb/>
            protendatur recta AC Z; </s>
            <s xml:id="echoid-s4797" xml:space="preserve">tum fiat BZ. </s>
            <s xml:id="echoid-s4798" xml:space="preserve">CZ:</s>
            <s xml:id="echoid-s4799" xml:space="preserve">: I. </s>
            <s xml:id="echoid-s4800" xml:space="preserve">R; </s>
            <s xml:id="echoid-s4801" xml:space="preserve">nec non di-
              <lb/>
            vidatur CZ in F, ut ſit FZ. </s>
            <s xml:id="echoid-s4802" xml:space="preserve">FC:</s>
            <s xml:id="echoid-s4803" xml:space="preserve">: I. </s>
            <s xml:id="echoid-s4804" xml:space="preserve">R; </s>
            <s xml:id="echoid-s4805" xml:space="preserve">& </s>
            <s xml:id="echoid-s4806" xml:space="preserve">centro F per Z deſcri-
              <lb/>
            batur circulus EG Z. </s>
            <s xml:id="echoid-s4807" xml:space="preserve">his peractis, accipiatur jam quilibet ad AC
              <lb/>
            parallelus MNP(convexis incidens an concavis partibus perinde
              <lb/>
            fuerit) dico ſi recta NC (ab incidentiæ nempe puncto per refrin-
              <lb/>
            gentis centrum ducta) circulo EGZprotracta occurrat in G; </s>
            <s xml:id="echoid-s4808" xml:space="preserve">&</s>
            <s xml:id="echoid-s4809" xml:space="preserve"/>
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