THE parts of a chair are the legs, the seat frame, the back, and the arms. Plate XL.

The seat frame, and in most instances all the rails, are doweled to the legs and back posts. The seat frame is stiffened by corner blocks screwed securely to the inner side. If these blocks are wide and well fastened, they add very materially to the strength of the chair. The upholstery blocks mentioned on page 31 also stiffen the framing. The conditions given the designer usually determine the use of the chair and how much of it is to be upholstered. With this information given, he is free to make the rest as he likes, and he decides upon the form and proportion of the chair as a whole without respect to detail. This may be studied in plan and elevation at a convenient scale, or perhaps in perspective, if the idea is sufficiently clear in the mind to do so. It is, however, only by means of the projection drawings that the true forms of the different parts may be known, and even though the sketch is made at once without their aid a knowledge of what they are like is necessary. Chairs, when drawn in side elevation, assume one of the five elementary forms shown on Plate VII., where attention is called to the relation of the supporting members to a vertical line. These outlines are drawn from actual examples, and are at the same scale for purposes of comparison.

The front elevation will appear like one of the three types shown on this plate. The one on the right, if drawn in side elevation, would have a straight back and straight legs; the one on the left would have the side elevation, like one of the first three illustrated; the one in the middle would appear in side elevation much the same as it does in the front, i. e., all legs and the back inclined. It is a drawing of a Windsor chair, with a solid wood seat, sometimes called the saddle seat, because of its shape. The legs and back posts are fastened in this seat by inserting the full size of the turning in holes bored for them, and the seat frame is omitted; but the legs are tied together by stretchers.

Italian and German chairs, with backs and legs of solid boards elaborately carved, appear in the same inclined form when drawn in elevation. The "scissor" pattern was originally a folding chair, but although the form is retained it is not always made to fold, though both folding and fixed chairs present a similar elevation. The plan of a chair seat approximates a square, a triangle, or a circle. The principal varieties, with the position of the legs in relation to the frame indicated by the shading, are shown on Plate VIII. The square plan, though not uncommon, is less frequently seen than the trapezoidal. This latter is perhaps the most used, either with the straight frame, as on the left of the dotted line in the illustration, or curved, as on the right. Triangular seats, though used in olden times, are not common now, except for corner seats.

The circular and composite plans are constantly employed. The composite form, made up of curves and marked "French," is the plan of the Louis XV. arm-chair, given as an example of rendering (Plate XXV.), and the plan on the right marked "Windsor" is that of a Windsor chair, similar to the "inclined form" (Plate VII.).

The outline of nearly all chair backs is either rectangular or trapezoidal (Plate IX.). If of the first, the back posts are perpendicular to the floor line, and the legs are the same distance apart at the floor as at the seat level.

If of the second form, the back posts are inclined to the floor line so that the legs are nearer together at the floor than at the seat level, and the back of the chair is proportionately wider at the top than it is at the seat. Though a chair may have a more complex and elaborate back than any of those taken as examples for illustration, an analysis of the outline will result in finding that it is based on one of these figures. The other four shapes illustrated are not as frequently used as the first two. This is particularly true of the polygonal and semicircular patterns.

Both of these are taken from French examples. The elliptical back is also a favorite form for French chairs. The shield-back is characteristic of chairs made by Hepplewhite about 1793, and called by many "Colonial." It is well to observe, while studying these outlines, a constructive principle common to all of them. Whatever the outline of the back it is made up of two vertical posts extending from the floor to a horizontal rail connecting them at the top; at the seat level is a horizontal rail (seat frame) ; and in some instances there is another horizontal rail at a greater or less distance above the seat.

PLATE VIII. ARM CHAIRS; SEAT PLANS SHOWING POSITION OFPLEGS.

Plate IX. OUTLINE OF CHAIR BACKS.

Plate.X. COMPOSITION OF BACK.

The student is to notice especially that the uprights (the back legs) are of one piece from the floor to the top rail of the back. This is often forgotten by beginners in chair designing, and weak, almost impossible shapes are given to the back as a result. The elliptical and shield-backs, though at first glance violating this rule, are really composed of the parts as mentioned above. A larger drawing of the shield-back is given on Plate XVII., showing by the dotted lines the prolongation of the lower part of the leg; and the joints where the top and bottom rails of the shield meet the uprights are also indicated. Another chair back is also shown on the plate illustrating the same principle. There is but one exception to the above method of construction, and that is, when a solid wood seat is used; similar to the saddle seated Windsor; the German Stuhle, with turned legs; and the Italian Scabelum, with its solid board supports. In this case the legs and the backs are separate. Each leg is inserted in holes for the purpose in the board seat.