Fabri, Honoré, Tractatus physicus de motu locali, 1646

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              <s id="N20D6C">
                <emph type="center"/>
                <emph type="italics"/>
              Theorema
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              91.
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              </s>
            </p>
            <p id="N20D78" type="main">
              <s id="N20D7A">
                <emph type="italics"/>
              Poteſt determinari proportio anguli huius refractionis motus, ſi cognoſcatur
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              reſiſtentia, qua medium reſistit perpendiculari
                <emph.end type="italics"/>
              ; </s>
              <s id="N20D85">v. g. ſi globus plumbeus ex
                <lb/>
              aëre perpendiculariter cadat in ſuperficiem aquæ, haud dubiè ipſam
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              aquam ſubit, ſed minore motu; </s>
              <s id="N20D91">quippe frangitur ab ipſa denſitate aquæ
                <lb/>
              vis primi impetus, quo ſcilicet per liberiorem aëra priùs ferebatur: </s>
              <s id="N20D97">vnde
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              ſi habeatur proportio reſiſtentiæ aquæ poſita linea incidentiæ perpendi­
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              culari, non eſt dubium, quin habeatur etiam reſiſtentia poſita linea in­
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              cidentiæ obliqua; nam eodem modo hoc determinandum eſt, quo ſuprà
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              determinatum fuit Th. 66. 67. v. g. in fig. </s>
              <s id="N20DA7">Th. 65. determinatio noua
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              poſita perpendiculari ſit ad priorem vt AZ ad AF, ita vt per mediam
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              aquam conficiat tantùm ſpatium A
                <foreign lang="grc">δ</foreign>
              v. g. eo tempore, quo in libero aë­
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              re conficit AC; </s>
              <s id="N20DB9">certè ſi linea incidentiæ ſit inclinata EA, determinatio
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              noua erit ad priorem, vt AY ad AE, vel AB; </s>
              <s id="N20DBF">igitur fiet mixta ex AY
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              AB, ſcilicet A
                <foreign lang="grc">υ</foreign>
              ; </s>
              <s id="N20DC9">non tamen eo tempore conficiet A
                <foreign lang="grc">υ</foreign>
              , quo conficiet
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              A
                <foreign lang="grc">δ</foreign>
              ; </s>
              <s id="N20DD7">quia ſcilicet omnes partes aquæ reſiſtunt, vt conſtat; </s>
              <s id="N20DDB">igitur con­
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              ficietur A
                <foreign lang="grc">θ</foreign>
              æqualis A
                <foreign lang="grc">δ</foreign>
              ; quæ porrò ſit proportio reſiſtentiæ, quæ mobi­
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              le retardat in aqua, & reſiſtentiæ, quæ idem retardat in aëre determina­
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              ri non poteſt, niſi primò cognoſcatur proportio grauitatis vtriuſque. </s>
              <s id="N20DEB">
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              Secundò, niſi ſciatur in quo poſita ſit hæc reſiſtentia: Tertiò, niſi per­
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              ſpectum ſit, an maiore nexu partes aquæ inter ſe copulentur, an mino­
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              re, vel æquali, de quo alias. </s>
              <s id="N20DF4">Equidem P. Merſennus lib.1.a.15. ſuæ ver­
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              ſionis aſſerit corpus graue per mediam aquam conficere 12. pedes ſpatij
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              eo
                <expan abbr="tẽpore">tempore</expan>
              , quo 48. percurrit in aëre, id eſt, tempore duorum ſecundorum. </s>
            </p>
            <p id="N20E01" type="main">
              <s id="N20E03">Obſeruabis autem hîc tantùm conſideratam fuiſſe lineam A
                <foreign lang="grc">θ</foreign>
              rectam
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              ſine noua determinatione, quæ ſcilicet inſenſibilis eſt, quando linea in­
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              cidentiæ non eſt tam obliqua, nec impetus tantarum virium. </s>
              <s id="N20E0E">Denique
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              obſeruabis cognito vno angulo motus refracti ad datum angulum inci­
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              dentiæ cognoſci facilè quemlibet alium, qui alteri angulo incidentiæ re­
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              ſpondeat, vt patet ex dictis: </s>
              <s id="N20E18">Vtrum verò anguli refractionum motus ex
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              aëre in aquam ſint iidem cum angulis refractionum luminis ex aqua in
                <lb/>
              aëra, examinabimus alibi: </s>
              <s id="N20E20">hæc interim ſufficiant de motu refracto; quem
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              tamen adhuc reflexum eſſe contendo, immò nulla eſt refractio in motu,
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              quæ non ſit reflexio, & nulla reflexio in lumine, quæ non ſit refractio, de
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              quo fusè alibi. </s>
            </p>
            <p id="N20E2A" type="main">
              <s id="N20E2C">
                <emph type="center"/>
                <emph type="italics"/>
              Theorema
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              92.
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              </s>
            </p>
            <p id="N20E38" type="main">
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              Aqua, quæ cadit in planum durum reſilit in mille partes quoquo verſum
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              ; </s>
              <s id="N20E43">
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              non certè, quòd partes inferiores pellantur à ſuperioribus, vt volunt ali­
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              qui; </s>
              <s id="N20E4A">ſed quòd facilè ſeparentur partes aquæ; </s>
              <s id="N20E4E">vnde non mirum eſt, ſi vel
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              modico impetu diſpergantur; </s>
              <s id="N20E54">quippe, vt corpus aliquod reflectatur in­
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              tegrum, id eſt ſine partium diſperſione, debet reſiſtentia vnionis partium
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              eſſe maior tota vi impetus ad nouam lineam determinati; </s>
              <s id="N20E5C">cur verò po­
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              tiùs vna guttula dextrorſum repercutiatur, quàm ſiniſtrorſum; </s>
              <s id="N20E62">certè alia
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              ratio eſſe non poteſt, niſi primò diuerſa figura tùm aquæ impactæ, tùm </s>
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