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

Page concordance

< >
Scan Original
21 3
22 4
23 5
24 6
25 7
26 8
27 9
28 10
29 11
30 12
31 13
32 14
33 15
34 16
35 17
36 18
37 19
38 20
39 21
40 22
41 23
42 24
43 25
44 26
45 27
46 28
47 29
48 30
49 31
50 32
< >
page |< < (11) of 393 > >|
    <echo version="1.0RC">
      <text xml:lang="la" type="free">
        <div xml:id="echoid-div9" type="section" level="1" n="9">
          <p>
            <s xml:id="echoid-s466" xml:space="preserve">
              <pb o="11" file="0029" n="29" rhead=""/>
            quæ circa radiorum inflectionem primitùs obveniunt) exiſtimo peten-
              <lb/>
            dam, quod lucis radius non mera ſit linea, verùm dimenſionibus om-
              <lb/>
            nimodis præditum corpus; </s>
            <s xml:id="echoid-s467" xml:space="preserve">utpote (juxta quæ præmonuimus) cylin-
              <lb/>
            dricum aut priſmaticum, pro figura corpuſculi, a quo oritur. </s>
            <s xml:id="echoid-s468" xml:space="preserve">Sup-
              <lb/>
            ponatur, aliquatenus illuſtrandi propoſiti ergò, Parallelepipedum
              <lb/>
              <note position="right" xlink:label="note-0029-01" xlink:href="note-0029-01a" xml:space="preserve">Fig. 3.</note>
            ABCDEFGH lucis radium obliquè ſpeculo incurrentem repræ-
              <lb/>
            ſentare; </s>
            <s xml:id="echoid-s469" xml:space="preserve">cujus latus B F applicetur ſpeculo, dum interea reliquum
              <lb/>
            ejus ſupra ſpeculi planum elevatur. </s>
            <s xml:id="echoid-s470" xml:space="preserve">Impedietur ergò Parallelogramum
              <lb/>
            ABFE, nè recta procedat; </s>
            <s xml:id="echoid-s471" xml:space="preserve">indè continget rectam BF aliquò ſupra
              <lb/>
            dictum planum reſilire. </s>
            <s xml:id="echoid-s472" xml:space="preserve">Verùm in allas ſaltem partes fiet hæc refle-
              <lb/>
            ctio, ſecundum quas rectus radii progreſſus, quoad ejus fieri poteſt,
              <lb/>
            quàm minimè pervertetur. </s>
            <s xml:id="echoid-s473" xml:space="preserve">Cùm enim is rectiſſimum curſum affectet,
              <lb/>
            eum (ex indole certa, perpetuáque lege naturæ) ſi perfectè nequit,
              <lb/>
            at tamen ut proximè conſequetur. </s>
            <s xml:id="echoid-s474" xml:space="preserve">Itaque cùm inter plana latera
              <lb/>
            ABDC, EFHG ſibimet oppoſita curſus ejus anteà dirigeretur, & </s>
            <s xml:id="echoid-s475" xml:space="preserve">
              <lb/>
            objecta ſuperficies nihil jam obſtet, quo minùs inter eadem plana, ta-
              <lb/>
            metſi ſurſum excuſſus, progrediatur, admodum liquet etiamnum inter
              <lb/>
            illa ſemitam ejus contineri; </s>
            <s xml:id="echoid-s476" xml:space="preserve">locumque ſeu plagam reflexionis eatenus
              <lb/>
            haud perperam determinari. </s>
            <s xml:id="echoid-s477" xml:space="preserve">Cæterùm eſt planum ABDC, eíque
              <lb/>
            oppoſitum EFGH ſpeculi plano rectum; </s>
            <s xml:id="echoid-s478" xml:space="preserve">quia Parallelepipedum
              <lb/>
            rectum ponitur, & </s>
            <s xml:id="echoid-s479" xml:space="preserve">ideò lateralisrecta B F in ſpeculi plano exiſtens,
              <lb/>
            planis ABDC, EFHG recta. </s>
            <s xml:id="echoid-s480" xml:space="preserve">Quocircà ſitotum hoc Paralleledipedum
              <lb/>
            ob exilitatem ſuam, aut Mathematicæ computationis gratiâ, pro recta
              <lb/>
            quaſi linea cenſeatur, erit pariter & </s>
            <s xml:id="echoid-s481" xml:space="preserve">reflexus radius etiam linea recta;
              <lb/>
            </s>
            <s xml:id="echoid-s482" xml:space="preserve">nec non uterque continebitur in ſuperficie ad ſpeculi planum recta. </s>
            <s xml:id="echoid-s483" xml:space="preserve">
              <lb/>
            Non diſſimili ratiocinio, ſi radius cylindri recti figura præditus admit-
              <lb/>
            tatur (qualis nimirum à corpore procurrente, vel impulſo producetur,
              <lb/>
            id ſi Sphæricum fuerit) etiam radius in ſuperficie plano ſpeculi recta
              <lb/>
            reflectionem oſtendetur ſubire. </s>
            <s xml:id="echoid-s484" xml:space="preserve">Speculi quippe plano rectus incidat
              <lb/>
            cylindrus ABDC; </s>
            <s xml:id="echoid-s485" xml:space="preserve">cujus baſes AMCN, BODP, axis XZ; </s>
            <s xml:id="echoid-s486" xml:space="preserve">
              <lb/>
              <note position="right" xlink:label="note-0029-02" xlink:href="note-0029-02a" xml:space="preserve">Fig. 4.</note>
            ità ſcilicet, ut baſis BODP ſpeculi planum contingat in B; </s>
            <s xml:id="echoid-s487" xml:space="preserve">reli-
              <lb/>
            quum ejus corpus (prout in figura depictum exhibetur) obliquè ſur-
              <lb/>
            gens ſupra planum emineat. </s>
            <s xml:id="echoid-s488" xml:space="preserve">Baſis autem diametri B D, P O ſeſe nor-
              <lb/>
            maliter ſecent; </s>
            <s xml:id="echoid-s489" xml:space="preserve">ac per ipſam P O, & </s>
            <s xml:id="echoid-s490" xml:space="preserve">axem ductum planum efficiat in
              <lb/>
            cylindro Parallelogrammum P O M N. </s>
            <s xml:id="echoid-s491" xml:space="preserve">Si jam per hujuſce latera
              <lb/>
            MO, NP ducta concipiantur duo plana axi parallela, cylindrúmque
              <lb/>
            contingentia, liquebit (ex antedictis cauſis pariter applicatis) totius
              <lb/>
            cylindri ductum inter hæc duo plana comprehendi, radiique reflecti-
              <lb/>
            onem inter ipſa definiri. </s>
            <s xml:id="echoid-s492" xml:space="preserve">Sunt autem hæc plana ſpeculi plano recta.
              <lb/>
            </s>
            <s xml:id="echoid-s493" xml:space="preserve">Sit enim recta G B H communis ſectio circnli B O D P, </s>
          </p>
        </div>
      </text>
    </echo>
Impressum