Fabri, Honoré, Tractatus physicus de motu locali, 1646

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              vniuerſale eſt, falſum eſſe conſtat; addunt aliqui eſſe mixtam æquiualen­
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              ter. </s>
              <s id="N2115A">Tertiò, cum ſit eadem potentia motrix applicata, tùm in K, tùm in
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              A; </s>
              <s id="N21160">certè debet eſſe idem impetus; </s>
              <s id="N21164">cum autem duæ lineæ K
                <foreign lang="grc">θ</foreign>
              K
                <foreign lang="grc">β</foreign>
              repræ­
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              ſentent duos impetus, qui concurrunt ad motum mixtum per KD (nam
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              hoc ipſi dicunt) certè duo ABAP ſimul ſumpti æquales eſſe deberent
                <lb/>
              duobus K
                <foreign lang="grc">θ</foreign>
              K
                <foreign lang="grc">β</foreign>
              , quod falſum eſt; quia KD ſit 4. ſitque angulus GDK
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              30.grad. </s>
              <s id="N21180">K
                <foreign lang="grc">θ</foreign>
              eſt 2. igitur collecta
                <foreign lang="grc">θ</foreign>
              K
                <foreign lang="grc">β</foreign>
              eſt 6. & eius quadratum 36. at
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              verò quadratum AB eſt 18. ergo quadratum collectæ ex ABAP eſt
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              32. igitur illa maior eſt. </s>
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              <s id="N21195">Sed iam ad aliam propoſitionem venio, in qua dicitur linea reflexio­
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              nis DX eſſe mixta ex D
                <foreign lang="grc">θ</foreign>
              D
                <foreign lang="grc">υ</foreign>
              quod falſum eſt; </s>
              <s id="N211A3">nam primò hoc dicis,
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              hoc proba poſitiuo argumento: </s>
              <s id="N211A9">Dices, quia non poteſt aliter explicari
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              æqualitas anguli reflexionis; </s>
              <s id="N211AF">bellè! nego antecedens; nam licèt nondum
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              verus illius modus explicatus non eſſet, proba tuum eſſe verum. </s>
              <s id="N211B5">Secundò
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              vel aliquid prioris determinationis manet, vel nihil; </s>
              <s id="N211BB">non primum, vt ipſi
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              volunt; </s>
              <s id="N211C1">alioqui DX eſſet mixta ex tribus ſcilicet DQ, D
                <foreign lang="grc">θ</foreign>
              , D
                <foreign lang="grc">υ</foreign>
              , quod
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              abſurdum eſt; </s>
              <s id="N211CF">quod ſi nihil remaneat prioris determinationis; </s>
              <s id="N211D3">ergo ni­
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              hil prioris impetus, quod etiam concedunt; </s>
              <s id="N211D9">igitur producitur nouus, ſci­
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              licet propter compreſſionem aëris, corporis reflexi, & reflectentis; </s>
              <s id="N211DF">ſed
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              profectò, licèt hoc totum verum eſſet, cùm illa compreſſio fieret in linea
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              quæ per centrum globi producitur, ſcilicet à puncto contactus, ſcilicet
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              in linea DG; </s>
              <s id="N211E9">certè per illam fieret repercuſſio; </s>
              <s id="N211ED">Tertiò tunc maxima eſt
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              percuſſio, cum linea incidentiæ eſt perpendicularis; </s>
              <s id="N211F3">igitur tunc eſſe de­
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              bet maxima vis compreſſionis; </s>
              <s id="N211F9">igitur maxima vis repercuſſionis, ſed eſt
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              tantùm vt DG; at verò, ſi linea incidentiæ ſit AD, vis repercuſſionis
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              erit, vt collecta ex DFDP quæ maior eſt priore. </s>
              <s id="N21201">Quartò, cur DX erit
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              potiùs mixta ex duabus D
                <foreign lang="grc">θ</foreign>
              , D
                <foreign lang="grc">υ</foreign>
              , quàm ex duabus aliis? </s>
              <s id="N2120E">Quintò, perinde
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              ſe habet planum reflectens, atque ſi globum ipſum pelleret, cùm nihil de­
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              terminationis prioris remaneat, vt ipſi volunt, ſed pelleret per ipſam
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              DG. Sextò, proba argumento poſitiuo eſſe mixtam DX ex D
                <foreign lang="grc">υ</foreign>
              , D
                <foreign lang="grc">θ</foreign>
              ; nam
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              hoc reuerâ fingis ſine ratione. </s>
              <s id="N21222">Septimò, præterea ſi corpus eſſet duriſſi­
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              mum minùs reflecti poſſet à plano duriſſimo, ſi nulla fieret compreſſio. </s>
              <s id="N21227">
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              Octauò proba mihi impetum priorem deſtrui per ſe; </s>
              <s id="N2122C">nam cùm ſit indif­
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              ferens ad omnes lineas, nunquam deſtruitur, niſi ſit fruſtrà; </s>
              <s id="N21232">hic autem
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              fruſtrà non eſt: </s>
              <s id="N21238">Itaque manifeſtum efficitur, non modò ex his principiis
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              non demonſtrari æqualitatem anguli reflexionis, ſed ne argumento qui­
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              dem probabili comprobari; quia tamen in noſtra demonſtratione multa
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              ſunt, quæ ipſis non probantur, breuiter recenſeo. </s>
            </p>
            <p id="N21242" type="main">
              <s id="N21244">Suppono primò, planum reflectens eſſe principium nouæ determina­
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              tionis, quod nemo inficiebitur. </s>
              <s id="N21249">Secundò, eſſe tantùm principium vnius
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              determinationis quia vnum principium eſt. </s>
              <s id="N2124E">Tertiò, per quamcunque li­
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              neam incidat globus in punctum D plani ſcilicet immobilis, eſt ſemper
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              idem punctum contactus & eadem
                <expan abbr="Tãgens">Tangens</expan>
              . </s>
              <s id="N2125A">Quartò, à puncto contactus
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              globi duci tantùm poſſe vnicam lineam ad centrum. </s>
              <s id="N2125F">Quintò, cum deter­
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              minationis terminus à quo ſit illud punctum contactus, per illam tan-</s>
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          </chap>
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