Vitruvius Pollio, I dieci libri dell?architettura, 1567

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    <archimedes>
      <text>
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                <p type="head">
                  <s id="s.001606">
                    <emph type="italics"/>
                  Dell' Arena. </s>
                  <s id="s.001607">Cap. IIII.
                    <emph.end type="italics"/>
                  </s>
                </p>
                <p type="main">
                  <s id="s.001608">MA nelle opere di cementi biſogna hauer cura di truouar la arena, accioche
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                  ella ſia buona a meſcolar la materia, nè habbia ſeco terra meſcolata. </s>
                  <s id="s.001609">Le ſpe­
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                  cie dell'arena, che ſi caua ſono queſte. </s>
                  <s id="s.001610">La nera, la bianca, la roſſa, il car­
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                  boncino. </s>
                  <s id="s.001611">Di queſte è ottima quella, che ſtroppicciata con le dita, cigola:
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                  ma quella che ſarà meſchiata con terra, non hauerà aſprezza. </s>
                  <s id="s.001612">Similmente ſe l'Arena get­
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                  tata ſopra una ueſte bianca, & poi crollata non laſcierà macchia, nè iui reſterà terra di
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                  ſotto, quella ſarà buona. </s>
                  <s id="s.001613">Ma ſe non ſaranno luoghi di caua, allhora ſarà neceſſario cer
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                  nirla dai fiumi, & dalle giare, & anche dal lito del mare: ma quella nelle murature, &
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                  ne i lauori ha queſti difetti, che difficilmente ſi aſciuga, nè doue ella ſi truoua il pa­
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                  rete ſopporta di eſſer continuamente di molto peſo aggrauato, ſe con qualche tralaſcia­
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                  mento dell' opera non ripoſa, & oltra di queſto riceue i uolti: & l'arena del mare ha que
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                  ſto male di piu, che quando i muri ſaranno coperti, & intonicati ſputando la ſalſugine ſi
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                  diſcioglieranno. </s>
                  <s id="s.001614">Ma le arene, che ſi cauano di foſſe, poſte in opera, preſto ſi aſciuga­
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                  no, & nelle coperte de i muri durano, ſopportando i uolti: ma biſogna cauarle di freſco,
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                  perche ſtando troppo allo ſcoperto ſi riſolueno in terreno per lo Sole, per la Luna, & per
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                  la brina: doue poi poſte in opera non ritengo i cementi, ma ſi ſtaccano, & cadeno, & i
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                  muri fatti con quelle non ſoſtengono i peſi. </s>
                  <s id="s.001615">Ma le arene che di freſco ſi cauano, ſe bene
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                  hanno tanta bontà nel murare, non ſono però utili nelle incroſtature, & coperte de i
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                  muri, perche la calce con la paglia meſcolata con la graſſezza di quella per la fortezza,
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                  che tiene, non puo ſeccarſi ſenza fiſſure. </s>
                  <s id="s.001616">Ma quella de i fiumi per la magrezza ſua, come
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                  l'Aſtraco, bene battuta, & impaſtata, riceue nelle coperte ſolidità, & fermezza. </s>
                </p>
                <p type="main">
                  <s id="s.001617">
                    <emph type="italics"/>
                  Vitruuio narra le ſorti dell'arena, i ſegni di conoſcerla, quello, che in caſo di neceſſità do­
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                  uemo fare, i difetti, & le utilità di quelle ſorti. </s>
                  <s id="s.001618">Plinio ſi ſerue di questo luogo al duodecimo
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                  Capo del trenteſimo quinto libro. </s>
                  <s id="s.001619">La ſoſianza della terra è in tre modi uariata; La groſſa è det
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                  ta arena. </s>
                  <s id="s.001620">La ſottile, argilla. </s>
                  <s id="s.001621">La mediocre, commune. </s>
                  <s id="s.001622">La arena è ſterile, & non è atta ad eſſer
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                  formata in modo alcuno. </s>
                  <s id="s.001623">L'argilla è buona, & per notrire le piante, & per eſſere adoper ata
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                  in molte forme. </s>
                  <s id="s.001624">Di queſta ſorte era quella terra bianca gia detta Taſconicem, della quale in
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                  Iſpagna ſopra gli alti monti ſi faceuano i luoghi alti dalle guardie, & a i dì noſtri ( come riferi­
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                  ſce l'Agricola ) è una torre di questa terra appreſſo Coruerco città di Saſſonia, piu ſicura dal
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                  fuoco, da i uenti, & dalle pioggie, che ſe fuſſe fatta di pietre, perche per la ſua grauità reſi­
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                  ſte all'impeto de i uenti, per lo fuoco s'indura; & non riceuendo l'humore, non ſi riempe d'acque;
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                  & però deue eſſer graſſa, ſottile & ſpeſſa. </s>
                  <s id="s.001625">Ma torniamo all'arena. </s>
                  <s id="s.001626">Trouaſi arena di caua. </s>
                  <s id="s.001627">
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                  queſta tiene il primo grado di bontà. </s>
                  <s id="s.001628">trouaſi anche arena di fiume ſotto'l primo ſuolo, & di
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                  torrente ſotto la balza, doue l'acque ſoendono. </s>
                  <s id="s.001629">truouaſi anche la marina: queſta ſe deue eſ
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                  ſere buona, biſogna, che negreggi, & ſia lucida come uetro. </s>
                  <s id="s.001630">i colori dell' arena ſono il nero, il
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                  bianco, & il roſſo. </s>
                  <s id="s.001631">La néra è aſſai buona, la bianca tra quelle di caua è la peggiore: la roſſa ſi
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                  uſaua a Roma: ma hora ſi uſa la nera detta pozzolana, che è molto buona. </s>
                  <s id="s.001632">Il Carboncino è ter
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                  ra arſa dal fuoco rinchiuſo ne i monti piu ſoda di terra non cotta, piu molle del tofo, & piu
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                  commendabile. </s>
                  <s id="s.001633">L'arena con giara meſcolata è utile alle fondamenta, & piu commendata la
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                  piu minuta, anguloſa, & ſenza terra. </s>
                  <s id="s.001634">Tra le marine la piu groſſa, & la piu uicina alle riue
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                  è la migliore. </s>
                  <s id="s.001635">preſto ſi ſecca, & preſto ſi bagna, & ſi disfà per lo ſalſo, & non ſoſtenta
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                  il peſo. </s>
                  <s id="s.001636">L'arena di fiume è buona per intonicare i mari. </s>
                  <s id="s.001637">l'arena di caua a i uolti continuati
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                  ſerue; ma è graſſa, tenace, & fa peli ne i pareti. </s>
                  <s id="s.001638">Delle ſpecie di caua, è migliore quella, che
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                  eſſendo ſtropicciata con le dita ſtride, che sdrucciolando giu de i panni bianchi, non laſcia nè ter
                    <emph.end type="italics"/>
                  </s>
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    </archimedes>