Chap. XXIV.

MASONRY.

Fig. »439.

Fig- 2490i

Fig. 24911

fig. 2483. the plan of thesame; fig. 2484. is theprofile or section, and fig.2485. its development;fig. 2489. is the plan ofan arch where the facesare not parallel; fig. 2490.is the profile, and fig.2491. the development;fig. 2494. is a skew arch,with the wall battering;fig. 2496. its profile, andfig. 2498. its development.The voussoirs fig. 2486.,

2488., and2487.,shown inperspective, belong to thearch, the plan of which

is at fig. 2 < *83. : thevoussoirs fig. 2493.,

2492., show those of thearch fig. 2489., and

2495., 2497., thoseof the inclined arch fig.2489.: these voussoirsneed no further descrip-tion than that they areto be cut first, as if forarches in walls, withtheir faces perpendi-cular, and then by themeans of the mould theprojecting parts to be cutoff are determined, for the"purpose of forming thecurve of the respectivefaces: to prevent thevoussoirs from sliding ontheir joints the ancientmasons used holes andnotches; in others mor-tises and tenons, whichfitted into each other,an example of which isseen in the Coliseum.

1 !^.^

Fig. 2491.

Fig. 2407

Fig 2490.

Fig. 2498