Cardano, Girolamo, De subtilitate, 1663

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              <s id="s.003054">
                <pb pagenum="424" xlink:href="016/01/073.jpg"/>
              crocea omnia videntur: multis etiam dolor
                <lb/>
              non leuis capitis contingit. </s>
              <s id="s.003055">Cauſa eſt, quod
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              lumen paucum eſt, & ob id croceum. </s>
              <s id="s.003056">Indi­
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              cat hoc aurora, quæ & ipſa crocea eſt, vnde
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              illud Virgilij:
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                <emph type="quote"/>
                <emph type="italics"/>
              Tithoni croceum linquens Aurora cubile.
                <emph.end type="italics"/>
                <emph.end type="quote"/>
              </s>
            </p>
            <p type="main">
              <s id="s.003057">Antiqui enim, Seruio teſte, ex Varronis
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              authoritate, diem à prima luce inchoabant:
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              quem & in quatuor partes diuidebant. </s>
              <s id="s.003058">Ha­
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              rum prima erat manè, quæ & aurora, à
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              Manum, quod eſt bonum: ſic enim ſalutare
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              ſe antiqui ſolebant, tempeſtiuè ſurgentes:
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              inde ortum ab ortu. </s>
              <s id="s.003059">Solis ad quartam horam
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              vſque: quòd Sol perpetuò aſcendere vide­
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              retur, appellabat: à quarta ad octauam vſ­
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              que meridiem, quaſi Sol meridiaret: & vſ­
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              que ad 22. occaſum, quòd deſcenderet, ac
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              tandem occultaretur. </s>
              <s id="s.003060">Vnde horæ hæ æqua­
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              les erant, ſcilicet 12. pars diei à Solis ortu
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              ad occaſum. </s>
              <s id="s.003061">Nox verò in quinque, veſpe­
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              ra, quæ & crepuſculum nocturnum, ſeu lux
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              dubia: conticinium cum obtenebraretur
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              aër: hoc ſe quieti tradebant: intempeſta,
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              quæ metas vigilantium excederet, & neque
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              ſurgentibus eſſet accommodata: erátque
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              tempus à 4. ad 8. horam inde gallicinium
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              ad 10. fermè, à qua ad auroram lucifer. </s>
              <s id="s.003062">Sed
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              vt ad propoſitum redeam, eadem ratione
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              in aëre fieri permutationem neceſſe eſt ma­
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              gnam, ob quam quibus caput eſt imbecil­
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              le, dolet. </s>
              <s id="s.003063">Verùm dices, nonne dum Sol ori­
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              tur, parum etiam luminis ad nos peruenit
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              & dum occidit, & tamen illud candidum
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              eſt, ſicut & quod paruo foramine per fe­
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              neſtram in obſcurum cubiculum ingreditur?
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              </s>
              <s id="s.003064">Sed cauſa huius eſt, quòd dum Sol oritur
                <arrow.to.target n="marg357"/>
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              aut occidit, parum temporis abſumit, ma­
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              net autem diu in deliquio: quòd ſi quis
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              primos radios orientis aut vltimos occiden­
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              tis Solis, qui non ex centro veniunt, tum
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              maximè procul inſpiciat, croceos abſque
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              dubio illos eſſe videbit. </s>
              <s id="s.003065">Ex his igitur duo
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              perſpicua ſunt: Solem vndequaque non ex
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              ſolo centro radios emittere: & tamen ra­
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              dios, qui ex centro emittuntur, eſſe vali­
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              diores: quod etſi non fatearis, modò pri­
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              mum concedas, nihil ad res demonſtrandas
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              detrimenti afferet. </s>
              <s id="s.003066">Verùm (vt dixi ) ex toto
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              Sole tanquam ex igne vndequaque radios
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              prodire claret, quoniam deliquij tempore
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              pars, quæ centro oppoſita eſt occupatur à
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              Luna, & tamen aër, & parietes illumi­
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              nantur. </s>
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            <p type="margin">
              <s id="s.003067">
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              Solem totum
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              & vnde­
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              quaque ra­
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              dios emitte­
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              re.</s>
            </p>
            <figure id="id.016.01.073.1.jpg" xlink:href="016/01/073/1.jpg" number="46"/>
            <p type="caption">
              <s id="s.003068">
                <emph type="italics"/>
              Speculum.
                <emph.end type="italics"/>
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              </s>
            </p>
            <p type="margin">
              <s id="s.003069">
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              Quomodo
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              ſpeculum
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              concauum
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              omnes radios
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              in vnum
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              colligat.</s>
            </p>
            <p type="main">
              <s id="s.003070">Eſt etiàm ratio ſpeculi concaui hoc
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              oſtendens, quoniam non aliter in vnum
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              punctum coire poſſent omnes radij, niſi à
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              toto Sole procederent. </s>
              <s id="s.003071">Finge tu ex centro
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              Solis ſolum illuſtrari ſpeculum, profectò
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              ſolus radius vnus in ſpeculi centrum reddi­
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              bit. </s>
              <s id="s.003072">Vnde ergo fit, vt in centro ſpeculi con­
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              caui ignis ſemper accendatur, & omnes ex
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              Sole radij coëant: hoc enim Euclides rectè
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              demonſtrauit in ſuis ſpecularibus. </s>
              <s id="s.003073">Nam ex
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              ABCDE in F centrum omnes radij inter K
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              & L reflectuntur, non ex vno tantùm cir­
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              culo, vnde in F ignis accenditur. </s>
            </p>
            <p type="main">
              <s id="s.003074">Sed meritò dubitabis: primò, cur radij, qui
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              in ſeipſos reflectuntur, hi autem ſoli ſunt
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              perpendiculares, validi ſint? </s>
              <s id="s.003075">Cauſa eſt mani­
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              feſta: qui enim reflectitur à perpendiculo, in
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              ſeipſum redit, vt ex E in F, ex K, quare con­
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              duplicatur radius ſecundum longitudinem
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              totus: qui autem ex alio puncto in EK re­
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              flectitur, illum ſecat, & abit: at qui ſecat, in
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              puncto ſecat, igitur nullum præbet vim.
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              </s>
              <s id="s.003076">Nam punctus cum careat quantitate, caret
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              & viribus: igitur etſi infiniti radij per eun­
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              dem punctum reflectantur, nihilo ſunt ro­
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              buſtiores. </s>
              <s id="s.003077">Nam quod eſt nihilum, quantum­
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              uis ingemines, nihil producit: igitur radiis,
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              qui non reflectuntur à perpendiculo, nulla
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              prorſus eſt vis, vt ſecent. </s>
              <s id="s.003078">Proximis tamen
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              ac proximioribus eò maior eſt vis, quoniam
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              radius radio proximus eſt, non quia ſecet in
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              puncto: nam ſectio nihil refert, cùm (vt di­
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              xi) in indiuiſibili fiat, ſed propinquitas: nam
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              iuxta longitudinem, diu & magno ſpacio,
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              ſi radius radio hæret, vtriuſque vis in vnum
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              coit, ac quaſi ingeminatur. </s>
              <s id="s.003079">Quaſi dixi,
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              quoniam ſolus a perpendiculo cùm in ſe re­
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              deat, etiam ſolus vim ſuam exquiſitè du­
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              plicat. </s>
            </p>
            <p type="margin">
              <s id="s.003080">
                <margin.target id="marg359"/>
              Propoſitio
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              vltima, cur
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              radij perpen­
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              diculares
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              ſoli ſint va­
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              lidi.</s>
            </p>
            <p type="main">
              <s id="s.003081">Altera dubitatio erat, ſi ſpeculum ſit ma­
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                <arrow.to.target n="marg360"/>
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              gnum ex parte KG, reflexi radij cur non il­
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              luminant circumſtantes partes circa F, vt
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              ſaltem claritas reddatur, verùm omnes hi
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              radij infra F reflectuntur? </s>
              <s id="s.003082">Nam ſi ducatur
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              radius ex E in G, angulus F G K maior eſt
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              recto in angulo F G E, igitur reflectetur
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              infra FG per angulum FGE: quare quantò
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              maius eſt ſpeculum, & maior etiam ſuæ
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              ſphæræ portio, eò magis atque celeriùs ac­
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              cendit. </s>
              <s id="s.003083">Huius tamen generis ſpeculum non
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              procul ignem accendere poteſt, cum ſemper
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              in centro radij cogantur. </s>
            </p>
            <p type="margin">
              <s id="s.003084">
                <margin.target id="marg360"/>
              Speculum
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              concauum
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              quò maius,
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              eò faciliùs
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              accendit.</s>
            </p>
            <p type="main">
              <s id="s.003085">Supereſt tertia dubitatio non leuis. </s>
              <s id="s.003086">Quo­
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                <arrow.to.target n="marg361"/>
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              niam radij, qui ex parte E C à puncto
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              K reflectuntur, vt ex K procedens à
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              puncto D verſus H reflectetur, & ſaltem
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              illuminabit partes iuxta F, contra experi­
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              mentum. </s>
              <s id="s.003087">Euidens eſt hoc magis in radiis
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              ex B & C in K deductis. </s>
              <s id="s.003088">Cauſa huius eſt,
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              quod ſparguntur, nullúſque eſt perpendicu­
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              laris radius, luménque in F ingens obſuſcat
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              proximas partes: debilior enim eſt radius
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              ex concauo ſpeculo reflexus, quàm ex
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              plano, qui labitur, ſi non ſit perpendicu­
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              laris. </s>
              <s id="s.003089">Cauſæ igitur roboris radiorum ſunt,
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              per ſe coitio à perpendiculari, vt in ca­
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              uis ſpeculis. </s>
              <s id="s.003090">Proxima huic eſt reflexio à
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              perpendiculari abſque coitione, vt in pla­
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              nis ſpeculis directè Soli expoſitis. </s>
              <s id="s.003091">Tertia ſuc­
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              cedit, reflexio non à perpendiculari, ſed </s>
            </p>
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    </archimedes>
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