The decorative weight of the various objects in a room will vary, other things being equal, directly with their mass; or, rather, with their mass as affected by the laws of linear perspective. Thus two windows three feet by six feet will, if uncurtained, have the same weight; and this weight will be practically equal to that of a bookcase of the same width and height. In judging of the effect of mass or area the mind attaches a superior importance to width as opposed to height. Thus a bookcase four feet wide and five feet high would weigh less, in a decorative sense, than would a case five feet wide and four feet high. The weight of any object is of course increased by sharply-defined or eccentric outline, striking ornament, or distinctive coloring.

The importance of color in determining the decorative weight of an object is in part absolute, but chiefly relative. Absolutely, without reference to their background, the several hues vary in their power of attracting attention directly with warmth and purity. Thus red will outweigh any of the other hues, with orange, yellow, green, blue and violet in order; while vermilion will outweigh maroon or any red degraded by the admixture of black or white, as emerald will outweigh myrtle or nile, and ultramarine will outweigh indigo or azure. In practice, however, the weight of a colored surface is very largely relative, and varies directly with its degree of contrast, in hue, tone, and texture, with the background against which it appears. Red hangings against a red wall will have less weight than hangings of old gold; while gold will have less than blue, and blue less than green. A satinwood chair, though brighter than one of mahogany, will weigh less against a champagne ground. Dark tones weigh heavily against a light background, and light tones against dark. Considered alone, a smooth texture having a high power of reflecting light will outweigh one that is loose and rough; but against a lustrous satin or damask wall a lustreless tapestry or rep chair covering will outweigh one of velvet or brocade, as Grueby pottery will outweigh porcelain.

It is evident that the difficulties of weighing the attractive forces which enter into a decorative balance tend to grow less in direct proportion to the likeness of the features, and that they disappear altogether when the balanced objects are exactly alike. To arrange a chair and a cabinet against a given wall space in such a way as to place the wall in balance may easily prove a problem. The problem becomes easier with two chairs of analogous size and shape, and progressively easier as the likenesses of the chairs in proportion, color and ornamental detail are progressively increased until, with two identical chairs, it becomes purely mechanical and could be solved by a child with a tape measure.

In decoration, then, as in mechanics, we have to do with two kinds of balance: that produced by arranging identical or closely analogous elements at equal distances from a real or ideal center; and that produced by arranging elements more or less unlike at unequal distances from the center. The first type, called bi-symmetric, or formal, balance, is easy to produce and so easy to see as to be perfectly obvious. The second type, called occult, or substitutional, balance, is more difficult to produce and more or less subtle. Which is to be preferred, and why? For the general answer to these questions we must turn, as in nearly every other question of practice, to considerations of fitness to purpose.

At the outset it is to be noted that the elements which in combination make up the organic whole of a furnished room vary widely in character and function, and that they are, in fact, divisible naturally into three classes: (a) the fixed decorations; (b) the furniture; and (c) the small, unimportant pieces and decorative accessories grouped by the French under the term decoration volante, or flying decoration.

The fixed decorations, which include the trim, fireplace, walls, floor, ceiling, doors, and windows with their hangings, are clearly structural in character. They are not fortuitous but rather integral parts of the framework or skeleton of the room. As such they are in their effect upon the mind properly permanent, immovable and obvious, and they ought to be made to reveal these characteristics immediately and unmistakably. Clearly, therefore, the fixed decorations ought to be characterized in a marked degree by formal balance.

The furniture of most rooms is of many kinds and sizes. In the living room, for example, some pieces, like the piano and bookcases, are immovable and semi-structural in character; others, like the davenport and reading table, are closely related by their size and importance to the structure of the room, and by their use to the changing moods and needs of the household; still others, like the smaller chairs and tables, which lend themselves to easy grouping and regrouping, are less structural and more intimate and personal. Varying widely in function and significance, these various pieces properly enter the general balance of the room in positions ranging from the symmetrical relationships usually appropriate to the large immovable pieces down to the occult relationships suitable to the arrangement of the small and unimportant pieces.

The flying decoration is made up of small screens, footstools, stands, lamps, pictures, pottery and similar fugitive pieces whose primary function is to contribute the personal touches necessary to individualize the room, to rob it of stiffness or heaviness, give it a note of gayety and animation, and establish among all its elements a sort of air de famille. Accordingly, such elements ought to serve as a tonic or corrective for the room, which would without them seem heavy, over-formal or dead. To serve this end the flying decoration must, as individual pieces and as groups, be distributed in positions of occult balance more or less easily perceptible, according to the size and purpose of the room and the motive of its decorative treatment.