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

Page concordance

< >
Scan Original
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
51 33
52 34
53 35
54 36
55 37
56 38
57 39
58 40
59 41
60 42
< >
page |< < (14) of 393 > >|
    <echo version="1.0RC">
      <text xml:lang="la" type="free">
        <div xml:id="echoid-div13" type="section" level="1" n="10">
          <p>
            <s xml:id="echoid-s559" xml:space="preserve">
              <pb o="14" file="0032" n="32" rhead=""/>
            cinnè penes vos eſto judicium. </s>
            <s xml:id="echoid-s560" xml:space="preserve">Non diffitebor autem aut penitus diſſi-
              <lb/>
            mulabo non eſſe nihil quod his objici poſſit, & </s>
            <s xml:id="echoid-s561" xml:space="preserve">dubitandi cauſam inji-
              <lb/>
            cere. </s>
            <s xml:id="echoid-s562" xml:space="preserve">Cur enim, percontetur aliquis, quando ſolum punctum B vet-
              <lb/>
            ſus A renitatur, & </s>
            <s xml:id="echoid-s563" xml:space="preserve">totum lineæ BD quod ſupereſt partes appetat
              <lb/>
            contrarias, non circa punctum quodpiam aliud in ipſa BD, puncto B
              <lb/>
            propinquius, ut puta circa X, potiùs iſta gyratio concipiatur peragen-
              <lb/>
            da? </s>
            <s xml:id="echoid-s564" xml:space="preserve">Reſpondeo quàm breviſſimè (quonia@ incitato curſu tendens ul-
              <lb/>
              <note position="left" xlink:label="note-0032-01" xlink:href="note-0032-01a" xml:space="preserve">Fig. 6.</note>
            teriùs æ grè remoras fert) id in natura conſtanter accidere, quum mo-
              <lb/>
            tus rectus in circularem degenerat, ut extremæ ſibimet adverſæ mobi-
              <lb/>
            lium partes omnem motum dirigant ac moderentur, reliquis ad illa-
              <lb/>
            rum ductum componentibus ſe, motúſque ſuos attemperantibus; </s>
            <s xml:id="echoid-s565" xml:space="preserve">ne-
              <lb/>
            que non his quos ob extremarum contraniſmum, atque conflictum
              <lb/>
            amittere neceſſe habent in illas transfundentibus; </s>
            <s xml:id="echoid-s566" xml:space="preserve">quo fit ut mediis
              <lb/>
            hinc indè quàm tardiſſimè dimotis extremæ velociùs revolvantur, Ita-
              <lb/>
            que cùm extrema puncta B, D partes in contrarium æquâ vi nitantur,
              <lb/>
            neque niſi circa medium punctum Z rotatio peragatur, quod effectant
              <lb/>
            aſſequi poſſint, id ſtatim fiet, & </s>
            <s xml:id="echoid-s567" xml:space="preserve">reliquæ partes haud gravatim obſe-
              <lb/>
            quentur. </s>
            <s xml:id="echoid-s568" xml:space="preserve">Nè dicam in recta BD nullum aliud punctum exiſtere, cui
              <lb/>
            præ aliis jure prærogativa competit, ut circa ipſum mobile libretur.
              <lb/>
            </s>
            <s xml:id="echoid-s569" xml:space="preserve">At pluribus abſtinens ad refractionis præcipuam legem haud abſimili
              <lb/>
            diſcurſu proliciendam atque declarandam accedo. </s>
            <s xml:id="echoid-s570" xml:space="preserve">Hanc nempe:</s>
            <s xml:id="echoid-s571" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s572" xml:space="preserve">IV. </s>
            <s xml:id="echoid-s573" xml:space="preserve">6. </s>
            <s xml:id="echoid-s574" xml:space="preserve">Radii lucis alteri cuipiam diſſimili perſpicuo (nimirum ho-
              <lb/>
            mogeneo quoad ſe) incidentes ità refringuntur, ut perpetuò recti ſi-
              <lb/>
            nus inclinationum, quas habent incidentes, proportionales ſint rectis
              <lb/>
            ſinubus inclinationum, quas obtinent refracti. </s>
            <s xml:id="echoid-s575" xml:space="preserve">Huic elucidando, ſta-
              <lb/>
            biliendóque decreto; </s>
            <s xml:id="echoid-s576" xml:space="preserve">Parallelogrammum ABDC lucis radium re-
              <lb/>
            præſentans impingat planæ ſuperficiei EF pellucidi medii (vel ſit recta
              <lb/>
            EF ſectio communis, ut in caſu præcedente, quod & </s>
            <s xml:id="echoid-s577" xml:space="preserve">abhinc ſemper
              <lb/>
            intelligatur) progreſſum ejus aliquatenus retundentis. </s>
            <s xml:id="echoid-s578" xml:space="preserve">Itaque medium
              <lb/>
            iſthoc ſubingrediens punctum B procedere, tardiùs quidem, attenta-
              <lb/>
            bit per rectam BG, ſeu peripſam AB protractam, intereà verò pun-
              <lb/>
            ctum D in primo durans medio motum ſuum priorem adurgebit in re-
              <lb/>
            cta CDH. </s>
            <s xml:id="echoid-s579" xml:space="preserve">Hos autem conatus, aliàs irritos futuros (nec enim utrum-
              <lb/>
            que poteſt rectum motum illud tardiùs, hoc velociùs incedendo conſer-
              <lb/>
            vare) quàm proximè conſequentur, modò circa punctum aliquod in
              <lb/>
            recta DB producta ſitum, puta quale Z, rotentur; </s>
            <s xml:id="echoid-s580" xml:space="preserve">ità ſcilicet ut dum
              <lb/>
            punctum D in medio rariori (rarius appello quod minùs reſiſtit, aut
              <lb/>
            retardat; </s>
            <s xml:id="echoid-s581" xml:space="preserve">ut & </s>
            <s xml:id="echoid-s582" xml:space="preserve">denſius quod motum magis reprimit, & </s>
            <s xml:id="echoid-s583" xml:space="preserve">tardiorem
              <lb/>
            reddit) velociùs latum deſcribit arcum majorem D δ; </s>
            <s xml:id="echoid-s584" xml:space="preserve">punctum </s>
          </p>
        </div>
      </text>
    </echo>
Impressum