1434
THEORY AND PRACTICE OF ENGINEERING.
Book II.
■ig. 2461
Fig. 2100-
Fig. 2463,
Fig. 2405.
Fig. 2409.
Fig. 2-1G8.
reversed; the lines indicate the joints of the soffite, and those dotted the projectionof the interior section; these are formed by means of the profile, on which is taken,according to the verticalor perpendicular face, thethickness corresponding toeach joint of the soffite,thus: fig. 2455. shows thesection and its corre-sponding lines. A mouldmust first be formedfor each of the voussoirs,
I, K, L, M, for the purposeof accurately tracingthem;one is shown in fig. 2459.marked K, and in thevoussoirs drawn in per-spective. The manner ofworking it is thus per-formed (fig. 2459.): theupper bed is first cut, andthe two parallel lines \71 and an are to he drawn, at a distance corresponding to the thick-ness to be given to the arch; then the two faces, \7te.v, and auy y at right angles
Fig. 2473.
Fig. 2471.