At Fig. 173, from k draw kr2 at right angles to r2 d. at Fig. 172, make h r equal to h2 r2 in Fig. 173, and from r draw r s at right angles tor rh; from the intersection of r s with the level line m q, through i, draw st; at Fig. 173. make h2 b2equal to q t in Fig. 172, and join b2 and r2; from a2, and from as many other points in the arcs, a2 l and k d, as is thought necessary, draw ordinates to r2 d at right angles to the latter; make r b (Fig. 175) equal in its length and in its divisions to the line r2 b2 in Fig. 173; from r, n, o, p, q, and l draw the lines r k, n d, o a, p e, q f, and l c at right angles to r b, and equal to r2 k, d2 s,f2 a2, etc., in Fig. 173; through the points thus found trace the curves k l and a c, and complete the face-mould, as shown in the figure. This mould is to be applied to a square-edged plank, with the edge, l b parallel to the edge of the plank. The rake-lines upon the edge of the plank are to be made to correspond to the angle s t h in Fig. 174. The thickness of stuff required for this mould is shown at Fig. 174, between the lines s t and u v - u v being drawn parallel to s t.