77. As examples of the species of working-drawings required for doors, we will give two specimens; the one from a building of modern architecture, and the other from a Gothic building.

Fig. 1, plate LV, is the elevation of an external door, with a light over it. It may either be made folding or to open in one, and framed to represent a folding-door. Fig. 2 shows half the plan of the door-way to double the size of the elevation; and, in practice, this plan is usually made of the full size of the parts. The lights over doors are now generally formed by metal bars.

78. When a door is framed to represent a folding-door, it is called a double-margined door. In framing a door of this kind, the middle stiles must appear to cross the top, lock, and bottom rails. Fig. 5, 6, and 7, show how this may be done; fig 5 is the double stile; fig 6 the side of the bottom rail; and fig. 7, the edge of the bottom rail with the double stile inserted. The joints are made to bevel a little, so that they may be perfectly close when the rail is driven to its place, but they should not be beveled more than is absolutely necessary for that purpose.

79. An elevation of an external door for a Gothic building is shown by fig. 3; and fig. 4 is the plan of the door and jamb to double the size of the elevation, in order to show the parts more distinctly. Doors of this kind are frequently ornamented by nail-heads along the mouldings; and lately such heads have been cast in iron; their peculiar form is shown in fig. 8; where A is the top of the head, and B its side, with part of the moulding. When the nail-heads are formed in wood, they are let in within the surface about a sixteenth of an inch.

Of Jib-Doors, Book-Doors, &c.

80. A JIB-DOOR is one intended to be concealed, either from its leading to a private room, or from there being no corresponding door, and it is therefore made flush with the surface of the wall, being generally canvassed and papered over, or painted the same as the room; the design being to conceal the door as much as possible, or to preserve the symmetry of the side of the room which it is in.

Fig. 1, plate LVI, represents the side of a room, in which KLMN is a jib-door, I the base moulding of the room, and H the surbase, both continued across the door.

Now, in order to make the jib-door open freely, the mouldings must be so cut that no point of the moving part may come in contact with the jamb of the fixed part. This may be done by forming the end of the moving part, and the end of the jamb or stationary part, in such a manner that all the horizontal sections may be circles described from the centre of the hinge. In short, by making the end of the base and surbase, and the edge of the jamb, the surface of a cylinder, of which the axis line of the hinges is the axis of the cylinder. This is shown by fig. 4, where A is part of the jamb; B represents a section of the door, upon which the iron containing the centre is fixed. C is the centre. The parallel lines in front represent the projections of the mouldings. Draw Cd perpendicular to the front line, and make de equal to Cd. Cd• from C, with the radius Ce, describe the circular line ef, and where the points of eC cut the parallel lines will be the extremities of the radii of the other circles.

Figure 2 exhibits the section of the surbase, marked H, in fig. 1; and B, fig. 3, is the elevation of the base, shown at I, fig. 1; and fig. 5 shows the section of the base moulding. 81. In libraries, concealed doors to private rooms or book-closets are frequently made to match the book-cases, and to appear as though the door was part of the book-case. For this

purpose, pieces of wood are formed to the shape of book-backs, and covered with leather, and gilt and lettered, so as to resemble real books. When the book-backs are well imitated, the deception is very complete.

Doors are also concealed by covering them with maps strained on canvas, and well varnished, the joint of the door being in the frame of the map; and where some device of this kind cannot be employed, the edges of the doors soon become soiled, and their appearance disagreeable; particularly where there is no other reason for employing them than to preserve the symmetry

of a room.

OF THE CONSTRUCTION OF WINDOWS.

82. WINDOWS are described by the manner in which they open, and are of three kinds: Sash-windows, Casements, and Sliding-casements.

83. Sash-windows are balanced by weights, and slide vertically. They are, for most purposes, both more convenient than other windows, and better adapted for keeping out the weather. 84. Casements open on hinges in the manner of doors, and they are usually employed in Gothic buildings, being more in character with that style of architecture than sash-windows. When casements are employed with other species of architecture, they are called French windows. The objection to these windows is the difficulty of making them water-tight, without rendering them very inconvenient to open and shut; otherwise they are well adapted for windows to walk out at on to a lawn or a balcony.

85. Sliding-casements are used only for cottage-windows, and they slide horizontally, and often have small rollers in the bottom rail to lessen the friction.

86. The frames of windows are usually made of yellow fir, or of part fir and part oak, and for frames, as well as for every other purpose, where wood is to be painted, it should be well seasoned.

Sashes and Casements for principal rooms are often made of oak; and sometimes sashes are made of mahogany. Neither sashes nor casements should be made slight, as, however well they may fit at first, they soon get out of order if made too slight. The thickness of sashes should never be less than of those called 14-inch sashes, which are about 14-inch when finished, and casements should be thicker.

Proportions of Windows.

87. THE stone sills of windows, unless they begin from, or nearly from, the floor, are generally fixed with the upper side thirty inches above the floor line, and the tops of the windows should be about th of the height of the room below the ceiling to allow space for the windowcornice, and for the cornice of the room. When there is more than one window in a room, it is usual to place them so, that, if the pier between two windows be divided into three parts, the jamb of each end window may be two of these parts distant from the wall.

Windows should never be very wide, because then the shutters become heavy and inconvenient, and get very soon out of order; also, wide openings weaken the walls of a building, but as rooms should be well lighted without making larger openings than is necessary, a rule for that purpose

is useful.