In practice the decorator must also be on guard against inartistic diagonals in choosing upholstery fabrics. It is a common practice to use a boldly designed printed linen at the windows of a room and also as slip covers for some of the over-stuffed furniture. Many of the most strikingly decorative linens, especially those adapted from old Persian textiles, contain a sharply accented vine which runs obliquely from one side of the fabric to the other. This is of course unobjectionable in hangings, because the folds break the movement; but when the same pattern runs vigorously from the bottom of one side of a wide chair back to the top of the other side the effect is unpleasing, because it destroys the atmosphere of repose which it is one of the functions of such a chair to create.

The three dimensions, height, width and depth, respectively suggest the ideas of spiritual elevation, stability and mystery. When the dimensions of a composition are normal they tend to neutralize each other, and the mind is conscious of no emotional significance. When any one is over-emphasized the value of the other two is diminished accordingly. It is almost never desirable to over-emphasize any dimension of a room; the more nearly its proportions approximate those that the eye regards as normal the more satisfactory the room will be. In the choice of individual units, however, the principle is constantly employed. Thus it is impossible to produce through the use of short, high tables, chairs and cabinets the impression of stability produced by long low ones; impossible to create by means of a mantel clock the sense of elevation - of calm indifference to the hurries and anxieties of life - created by a hall clock; impossible to effect in any room without draperies the slight but intriguing sense of mystery and charm possessed by a room with deep and carefully arranged hangings.

Plate IV. - Greek vases which illustrate the differences in emotional effect between the circle and the oval as employed in decorative composition.

Courtesy of the British Museum.

Shapes, whether they appear as simple geometrical forms, or as compositions based upon or roughly defined or outlined by such forms, possess emotional significances which depend in part upon the character of their bounding lines and in part upon their proportions. Thus the square suggests strength and solidity because it combines equally the firmness and support of vertical lines and the repose of horizontals. The straight lines which define it make it obvious, however, while the equality of its dimensions deprives it of subtlety and tends to make it monotonous and therefore of limited value in decorative design. Square rooms are for this reason relatively uninteresting, and so are square wall spaces, windows, and fireplaces, and square rugs, tables, chairbacks, bookcases and pictures. What is true of the square is of course equally true of the cube. Cabinets, stools, seats or stands cubical in shape are rarely good-looking, unless, as sometimes happens, their beauty of carving or surface ornament obscures their tedious forms; while the big cubical chairs so often seen are esthetically tiresome and physically uncomfortable as well.

The oblong is the commonest form in decorative art, where it appears in floors, ceilings, walls, doors, and windows, in rugs, chairs, tables, bookcases and books, and in fact in nearly every object of use or ornament. Like the square, the oblong combines straight vertical and horizontal lines, which tend to make it obvious, but its extensions are never in equilibrium and the form therefore possesses an interest lacking in the simpler form. The beauty and decorative value of oblong shapes depends chiefly upon the subtlety of their proportions, and will be discussed in the chapter dealing with that subject, as will the use of vertical or horizontal oblongs in the convergent expression of emotional ideas.

The triangle appears in decoration both as a motive and as a principle of composition. When resting upon its base it expresses a subtle quality of animation or movement in repose - the two diagonal lines contributing the idea of movement and its broad base, as contrasted with its pointed apex, the idea of repose. In the isosceles triangle the two lines of movement are equal, and the figure accordingly suggests a symmetrical or balanced activity. It appears in lamp-shades, mantel clocks, the pediments of bookcases and highboys, and the supports of benches and tables; and as a principle of composition it is constantly employed by the decorator to give an effect of unity and balanced activity in the arrangement of mirror and console table, chair groupings, and in the disposition of pictures, pottery, or other small objects upon or above cabinets, mantels or bookcases. The isosceles triangle resting upon its point is occasionally employed in the design of fabrics and wall papers, where it yields an elusive effect of flame-like motion. The same motive is frequently found in Turcoman rugs, where it symbolizes the altars of an earlier faith, and the flame that anciently burned upon them.

Curved forms are easier to see than those of rectangular outline, and are therefore in general more agreeable. They vary in subtlety and in esthetic interest according to their outline. The circle, whose bounding line forever returns upon itself, suggests the ideas of completeness and finality. This quality renders it somewhat monotonous when used as a decorative unit, though it is of great value when used as the basis of repeating pattern. In the decoration of the dining room the table is of course the focal point - the motive to whose proper setting-out all other decorative elements are subordinated. And since a dining table is sufficiently large and massive to dominate the room it often happens that this very effect of completeness makes a round table more valuable deco-ratively than an oblong one. In the living room, on the contrary, large round tables are ordinarily objectionable, not only by reason of the lack of subtlety in their proportions, but also because they are out of harmony with the prevailing oblongs, being unlike them both in outline and in proportions. For the same reason circular mirrors, pictures and other wall ornaments do not compose well with the wall spaces. This objection does not apply, of course, to small occasional tables and other little circular forms which make themselves felt only as piquant accents in the general composition of the room; but in the design of larger units the circle is normally employed only as a device for securing emphasis through contrast.

The ellipse and the oval have a longer and a shorter axis, and therefore bear the same relation to the circle that the oblong bears to the square. They are more agreeable than the circle physiologically because, owing to the peculiar construction of the eyes, they are physically easier to see. They are far more agreeable emotionally, in part because of the subtlety inherent in the constant change of direction of their bounding lines, and in part because there is in the rhythmic alternation of these changes, and in the symmetrical swell and subsidence of the forms themselves, a hint of the mysterious dualism of life - of the flow and ebb, systole and diastole, inspiration and aspiration whence arises that sense of harmonious completeness which is the basic esthetic condition.