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-s8991" xml:space="preserve">
              <pb o="29" file="0207" n="222" rhead=""/>
            modi ſuppoſita linearum generatione poterimus indipiſci. </s>
            <s xml:id="echoid-s8992" xml:space="preserve">Simpli-
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            citatis autem & </s>
            <s xml:id="echoid-s8993" xml:space="preserve">perſpicuitatis cauſâ ſupponamus alterum ex his
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            motibus, rectæ nimirum paralleliſmum ſervantis, eſſe ſemper uni-
              <lb/>
            formem, & </s>
            <s xml:id="echoid-s8994" xml:space="preserve">quænam ex alterius quoad velocitatem generalibus
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            differentiis generales emergant linearum productarum affectiones ad-
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            nitamur elicere. </s>
            <s xml:id="echoid-s8995" xml:space="preserve">Adnitamur inquam, at proxima lectione.</s>
            <s xml:id="echoid-s8996" xml:space="preserve"/>
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        </div>
        <div xml:id="echoid-div222" type="section" level="1" n="31">
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            <emph style="sc">Lect</emph>
          . IV.</head>
          <p>
            <s xml:id="echoid-s8997" xml:space="preserve">Propoſitum eſt nobis è compoſitione motuum (qualem proximè
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            deſcripſimus) emergentes linearum affectiones indagare ac ex-
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              <note position="right" xlink:label="note-0207-01" xlink:href="note-0207-01a" xml:space="preserve">Fig. 18.</note>
            ponere. </s>
            <s xml:id="echoid-s8998" xml:space="preserve">Quorſum imprimìs methodi cauſà repeto ſi recta AZ per
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            rectam AY ſibi perpetuò parallela feratur uniformiter, et in ea
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            quoque punctum M uniformiter deportetur, quâvis velocitate, li-
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            nea recta proveniet. </s>
            <s xml:id="echoid-s8999" xml:space="preserve">Sumantur enim duæ quævis lineæ mobilis
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            AZ poſitiones, ad B ſcilicet & </s>
            <s xml:id="echoid-s9000" xml:space="preserve">C; </s>
            <s xml:id="echoid-s9001" xml:space="preserve">& </s>
            <s xml:id="echoid-s9002" xml:space="preserve">quia motus per AY po-
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            nitur uniformis, erunt decurſa ſpatia AB, AC ad ſe, ut _Tempo-_
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            _ra_; </s>
            <s xml:id="echoid-s9003" xml:space="preserve">ſed et ob motum uniformem puncti M etiam rectæ BM,
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            CM ſe habebunt ut eadem tempora; </s>
            <s xml:id="echoid-s9004" xml:space="preserve">eſt igitur AB. </s>
            <s xml:id="echoid-s9005" xml:space="preserve">AC:</s>
            <s xml:id="echoid-s9006" xml:space="preserve">:
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            BM. </s>
            <s xml:id="echoid-s9007" xml:space="preserve">CM. </s>
            <s xml:id="echoid-s9008" xml:space="preserve">Unde liquet puncta A, M, M in una recta linea ex-
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            iſtere. </s>
            <s xml:id="echoid-s9009" xml:space="preserve">Parique ratione conſtat idem de punctis omnibuſcunque,
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            quibus punctum M per totum ſuum curſum inſiſtit, aut coincidit,
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            Supponatur ſecundò punctum M motu continuo increſcente deſerri
              <lb/>
            (juxta quamlibet velocitatis rationem, regulari modo quocunque
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            nil intereſt, an irregulari) aio _ſuppoſitionem banc conſectari progeni-_
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            _tarum linearum quas apponemus proprietates generales_ (quales uni
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            tali linearum generi convenientes certè præſtat ex unimoda com-
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            muni generatione ſimul univerſas elicere, quàm de ſingulis, ut
              <lb/>
              <note position="right" xlink:label="note-0207-02" xlink:href="note-0207-02a" xml:space="preserve">Fig. 19.</note>
            paſſim fieri ſolet, ſingulas ſeparatim oſtendere.) </s>
            <s xml:id="echoid-s9010" xml:space="preserve">Notetur inte-
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            reà, quòd brevitatis cauſâ motum parallelum uniformem rectæ AZ
              <lb/>
            per AY appellabo ſubinde _motum tranſverſum_; </s>
            <s xml:id="echoid-s9011" xml:space="preserve">puncti verò mo-
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            ventis ab A in linea AZ motum vocitabo _deſcenſum_, aut _motum_
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            _deſcendentem_, habito ſcilicet ad figuram exhibitam reſpectu. </s>
            <s xml:id="echoid-s9012" xml:space="preserve">Item
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            quòd, ob motûs per AY et ei parallelas uniformitatem, poſſit
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            ea cum ipſius partibus motûs tempus, et ejus partes repræſentare.
              <lb/>
            </s>
            <s xml:id="echoid-s9013" xml:space="preserve">Jam ad dictas proprietates expendendas accedo.</s>
            <s xml:id="echoid-s9014" xml:space="preserve"/>
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