Alberti, Leone Battista, Architecture, 1755

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              <s>
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              without Interruption; but only firſt to
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              ſtrengthen the Places you intend for the Seats
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              or Beds of your Columns, and then from one
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              to the other draw Arches with their Backs
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              downwards, ſo that the Plane or Level of the
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              Area will be the Chord of thoſe Arches; as
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                <arrow.to.target n="marg7"/>
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              you may ſee by the Plate of the Page 41. let
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              B. </s>
              <s>For ſtanding thus, they will be leſs apt to
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              force their Way into the Earth in any one
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              Place, the Weight being counterpos'd and
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              thrown equally on both Sides on the Props of
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              the Arches. </s>
              <s>And how apt Columns are to
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              drive into the Ground, by means of the great
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              Preſſure of the Weight laid upon them, is
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              manifeſt from that Corner of the noble Tem­
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              ple of
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              Veſpaſian
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              that ſtands to the North­
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              Weſt. </s>
              <s>For being deſirous to leave the publick
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              Way, which was interrupted by that Angle, a
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              free and open Paſſage underneath, they broke
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              the Area of their Platform and turn'd an Arch
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              againſt the Wall, leaving that Corner as a Sort
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              of Plaiſter on the other Side of the Paſſage,
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              and fortifying it, as well as poſſible, with ſtout
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              Work, and with the Aſſiſtance of a Buttreſs.
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              </s>
              <s>Yet this at laſt, by the vaſt Weight of ſo great
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              a Building, and the giving Way of the Earth,
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              became ruinous. </s>
              <s>But let this ſuffice upon this
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              Head.</s>
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              *</s>
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            <p type="head">
              <s>CHAP. VI.</s>
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              <s>
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              That there ought to be Vents left open in thick Walls from the Bottom to the
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              Top; the Difference between the Wall and the Foundation; the principal
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              Parts of the Wall; the three Methods of Walling; the Materials and
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              Form of the firſt Courſe or Layer.
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              </s>
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              <s>The Foundations being laid, we come
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              next to the Wall. </s>
              <s>But I will not omit
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              here a Precaution which belongs as well to the
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              Compleating of the Foundation as to the
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              Structure of the Wall. </s>
              <s>In large Buildings,
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              where the Wall is to be very thick, we ought
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              to leave Vents and Tunnels in the Body of the
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              Wall, at moderate Diſtances one from the other,
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              from the Foundation quite to the Top, through
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              which any Vapour or Damp that may happen
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              to engender or gather under Ground may have
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              free Paſſage without damaging the Work. </s>
              <s>The
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              Ancients in ſome of theſe Vents were uſed to
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              make winding Stairs, as well for the Sake of the
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              Beauty of the Contrivance itſelf, as for the
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              Convenience of paſſing up to the Top of the
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              Edifice, and perhaps too for the Saving of ſome
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              Expence. </s>
              <s>But to return to our Subject; be­
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              tween the Foundation and the naked Wall there
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              is this Difference, that the former having the
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              Support of the Sides of the Trench, may be made
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              of nothing but Rubbiſh, whereas the Latter con­
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              ſiſts of Variety of Parts, as we ſhall hereafter
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              ſhew. </s>
              <s>The principal Parts of the Wall are
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              theſe; firſt, the bottom Part, which begins
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              immediately from the Level of the Foundati­
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              ons; this we call the firſt Courſe laid upon the
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              Level, or the Courſe riſing from the Ground:
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              The middle Parts, which girt and ſurround
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              the Wall, we ſhall call the ſecond Courſe: The
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              higheſt Parts, laſtly, that is to ſay, thoſe which
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              ſupport the top Roof, we call Cornices. </s>
              <s>Some
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              of the principal Parts or rather the prin­
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              cipal Parts of all are the Corners of the
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              Wall, and the Pilaſters, or Columns, or any
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              thing elſe in their ſtead ſet in the Wall to ſup­
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              port the Beams and Arches of the Covering;
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              all which are comprized under the Name of
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              Bones or Ribs. </s>
              <s>Likewiſe the Jambs on each
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              Side of all Openings partake of the Nature both
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              of Corners and of Columns. </s>
              <s>Moreover, the
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              Coverings of Openings, that is to ſay, the Lin­
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              tels or Tranſoms, whether ſtrait or arched, are
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              alſo reckoned among the Bones. </s>
              <s>And indeed
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              I take an Arch to be nothing more than a Beam
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              bent, and the Beam or Tranſom to be only a
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              Column laid croſſways. </s>
              <s>Thoſe Parts which
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              interfere or lie between theſe principal Parts,
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              are very properly called Fillers up. </s>
              <s>There are
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              ſome Things throughout the whole Wall
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              which agree each with ſome one of the Parts
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              we have here ſpoken of; that is to ſay, the fill­
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              ing up or cramming of the Middle of the Wall,
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              and the two Barks or Shells of each Side,
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              whereof that without is to bear the Sun and
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              Weather, and that within is to give Shade and
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              Shelter to the Inſide of the Platform. </s>
              <s>The
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              Rules for theſe Shells and for their ſtuffing are
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              various, according to the Variety of Structures.
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              </s>
              <s>The different Sorts of Structures are theſe; the
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              ordinary Sort, the chequer Sort and the Irregu­
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              lar: And here it may not be amiſs to take
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              </s>
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