of course, seen in the drawing; c c are the expanding projecting pieces or tenons; these are passed into the parts, d d, cut out on the edge of bb; e e shows the return face of b b, this being, of course, at right angles to the face of the other piece, a a; the ends of the piece c c are shown at ff. Fig. 126 shows the pieces put together-a a corresponding to piece a a in fig. 125, with expanding tenons, c c, the ends of which show at d, corresponding to f in fig. 125; e in fig. 126 being one of the parts cut out of ff, corresponding to d d in fig. 125. In fig. 127, a a show the position and shape which the hole, b b, fig. 125, presents, as seen from the inside face of b b in that figure. In what is known as "lap dovetailing," the end, d, fig. 126, of expanding piece, c, is concealed, and only the flat sides are shown at one side; this is effected by shortening the expanding projection, as at a a, fig. 128, and cutting off the indentation of the other piece, so as not to go through the piece entirely, as in fig. 125, a solid piece, bb, being left. In fig. 128, c c shows the appearance of the only side at which the joint is seen; this is further illustrated in fig. 129, a showing one piece cut out completely as in common dovetailing, as in fig. 125; b, the expanding mortise cut short so as not to go through, leaving a piece, as at c. The kind of dovetailing known as "mitre," used for superior work where the joints are entirely concealed, will be illustrated in Building Construction, Advanced Course, in this series. Fig. 129. Brackets. In fixing plaster cornices to rooms, as at aaa, fig. 130, the plaster is worked out on the outside of pieces of wood, as bb, the outer edges of which are cut so as to follow roughly the outline of moulding. The Fig. 130. architrave." The bracket for the cornice may be made with its outer edge cut to the several shapes of the part indicated, and may be built up of separate pieces of timber dowelled and jointed together, as in making wooden pillars; this and other methods of joining timber will be found in the Advanced Course named above. We have already shown how architraves are secured to grounds. Architraves are of two kinds-single and double. In fig. 131 is illustrated a "single mouldings are at one end only, the when a moulding is placed in the middle, as at a in fig. 132, the architrave is called a "double architrave." CHAPTER IV. WORK IN LEAD AND IRON. IN the Advanced Course on Building Construction, in this series, the reader will find remarks on the above materials-their nature and constructive peculiarities. We now proceed to point out briefly some of the more simple parts of construction in which they are employed, taking up lead first. 32. Lead flashings are the strips or bands of sheet lead, generally 8 to 9 inches in breadth, and weighing about 5 to 6 lbs. the square foot, which cover the joints made at the junction of the roofing boards, or slates to chimneys, &c. In fig. 133, we give a section at a, and part elevation at b, of flashing to a chimney stalk; bb is the flashing or strip of lead; the joint, at c, is covered by the piece of sheet lead, d, the end, e, of which-2 inches in length d 3/4" Fig. 133. is passed into the joint, f, of the brick-work, part of the mortar being scraped out to allow of e being inserted. Fig. 134 represents the ordinary mode of employing lead flashing for gutters at the back of a parapet wall. The edge, a, of the lead is inserted into the joint, b, of the brickwork for about 1 inch in width, the mortar being taken out for this distance between the joints to admit of the lead being entered. It is then bent vertically downwards at c, against the wall, d, then returned horizontally, as at e, over the surface of the gutter, f, and up under the slates, tiles, or roof covering, at g g, some 5 or 7 inches. 7 inches. Fig. 4, Plate XV., illustrates another method of finishing the part at a, fig. 134. Fig 7, Plate XV., illustrates the gutter at the outer or parapet side of a flat roof; fig. 8 the |