Bélidor, Bernard Forest de, La science des ingenieurs dans la conduite des travaux de fortification et d' architecture civile

Table of handwritten notes

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              <s xml:id="echoid-s3135" xml:space="preserve">
                <pb o="50" file="0158" n="161" rhead="LA SCIENCE DES INGENIEURS,"/>
              pieds; </s>
              <s xml:id="echoid-s3136" xml:space="preserve">mais la ſolution de ce Probléme dépend plûtôt de l’intelligen-
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              ce de ceux qui font travailler, que de la Géometrie: </s>
              <s xml:id="echoid-s3137" xml:space="preserve">c’eſt pourquoi
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              il ſemble que le meilleur parti eſt de s’en raporter à l’experience;
                <lb/>
              </s>
              <s xml:id="echoid-s3138" xml:space="preserve">c’eſt-à-dire d’examiner avec attention les anciens monumens de cette
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              eſpece, afin qu’ayant reconnu la qualité des pierres qu’on y a em-
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              ployé, la longueur des vouſſoirs à pluſieurs grandeurs d’Arches dif-
                <lb/>
              férentes, on ſoit en état de calculer une table qui puiſſe ſervir dans
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              tous les cas qu’on peut rencontrer. </s>
              <s xml:id="echoid-s3139" xml:space="preserve">C’eſt ce que Mr. </s>
              <s xml:id="echoid-s3140" xml:space="preserve">Gautier a fait: </s>
              <s xml:id="echoid-s3141" xml:space="preserve">
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              nul n’étoit plus capable que lui de remplir un pareil deſſein; </s>
              <s xml:id="echoid-s3142" xml:space="preserve">il a
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              vû & </s>
              <s xml:id="echoid-s3143" xml:space="preserve">fait la deſcription des plus beaux Ponts qui ont été bâtis en
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              France, tant par les anciens que par les modernes: </s>
              <s xml:id="echoid-s3144" xml:space="preserve">ainſi, il me
                <lb/>
              ſuffira de raporter la Table qu’il a calculée pour la portée des vouſ-
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              ſoirs; </s>
              <s xml:id="echoid-s3145" xml:space="preserve">on verra qu’il a eû égard aux pierres dures & </s>
              <s xml:id="echoid-s3146" xml:space="preserve">à celles qui ne
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              le ſeroient pas, afin qu’on ait recours à la colomne dont la pierre
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              auroit quelque raport avec celle qu’on veut employer. </s>
              <s xml:id="echoid-s3147" xml:space="preserve">Ceux, qui
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              n’ont pas une grande connoiſſance des travaux, ſeront peut-être
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              ſurpris de voir dans la colomne où l’on ſupoſe la pierre tendre des
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              vouſſoirs de 8 & </s>
              <s xml:id="echoid-s3148" xml:space="preserve">même de 9 pieds de longueur, par la difficulté
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              qu’il y auroit d’avoir des pierres d’un ſi grand apareil; </s>
              <s xml:id="echoid-s3149" xml:space="preserve">auſſi ne pré-
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              tend-on pas que ces vouſſoirs ſoient abſolument compoſés d’une
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              ſeule pierre, puiſque quand on n’en a pas d’aſſés grandes on les al-
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              longe pour faire ce qu’on apelle des vouſſoirs ſans fin. </s>
              <s xml:id="echoid-s3150" xml:space="preserve">C’eſt ainſi qu’on
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              en a uſé pour conſtruire le Pont Royal des Thuilleries à Paris.</s>
              <s xml:id="echoid-s3151" xml:space="preserve"/>
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              <s xml:id="echoid-s3152" xml:space="preserve">La largeur, que l’on doit donner aux Piles des Ponts par raport à
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              l’ouverture des Arches, eſt encore une difficulté ſur laquelle les Ar-
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              chitectes ne s’accordent point, & </s>
              <s xml:id="echoid-s3153" xml:space="preserve">que la Geometrie paroît ne pouvoir
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              entreprendre, puiſqu’elle dépend abſolument de la conſiſtance de la
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              pierre: </s>
              <s xml:id="echoid-s3154" xml:space="preserve">car comme il s’agit de rendre les Piles aſſés fortes pour
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              ſoutenir le poids des Arches, & </s>
              <s xml:id="echoid-s3155" xml:space="preserve">tout ce qu’elles peuvent porter, il
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              n’y a pas de doute que la pile qui n’auroit qu’une mediocre largeur,
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              & </s>
              <s xml:id="echoid-s3156" xml:space="preserve">qui ſeroit conſtruite de bonne & </s>
              <s xml:id="echoid-s3157" xml:space="preserve">grande Pierre de Taille, ne ſou-
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              tienne plûtôt une Arche de 15 toiſes d’ouverture, qu’une autre
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              Pile qui auroit deux fois plus de largeur, mais qui n’auroit que le
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              parement de Pierre dure, & </s>
              <s xml:id="echoid-s3158" xml:space="preserve">le dedans rempli de mauvais moîlon,
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              n’en ſoûtiendroit une de huit toiſes. </s>
              <s xml:id="echoid-s3159" xml:space="preserve">Cependant, il eſt de conſéquen-
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              ce de ſe ſervir de bonne Pierre, pour n’être pas contraint de donner
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              une trop grande largeur aux Piles, parce que ſi le lit de la Rivierre
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              ſur laquelle on veut faire un Pont eſt reſſerré, il eſt à craindre que le
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              courant de l’eau, ſe trouvant gêné, ne renverſe le Pont dans le tems
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              des grandes inondations, comme cela arrive aſſés ſouvent. </s>
              <s xml:id="echoid-s3160" xml:space="preserve">Un autre
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              inconvenient encore des Piles trop larges; </s>
              <s xml:id="echoid-s3161" xml:space="preserve">c’eſt que leurs avant-becs </s>
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