This thought would be incomplete unless a caution were given in regard to the intensity of the rug or parts of it. The most effective rug is that in which the whole is keyed by one colour with all others subordinating themselves to this keyed idea. If this is not possible, intensity relations, as well as value relations, should be so close that no one part of the rug seems unduly important. As has been said, no part of the floor is a picture gallery or place to exploit shapes, forms, or colours at the expense of the tone unit for which the floor stands. If, on the other hand, any part of the rug must be intense, the law of intensity as to areas should certainly be observed and in a most conservative manner.

Let the interesting and vitally decorative spots and lines of the room have the intense colour emphasis. Let this appear also in single objects, and the third or intensity quality of colours will be considered in a way that makes this quality a fundamental force in interior decoration.

A knowledge of the qualities of each colour, its hue, tone, value and intensity, should lead to a conscious, sensible application of that knowledge in the fields that have been suggested. This leads naturally to the question of harmony in colour, which is essential to the selection and arrangement of a scheme for furnishing a room.

By harmony is meant agreement or concord. When there is perfect agreement, complete harmony results and a somewhat monotonous condition is felt. In music the major scale is the simplest expression of tonal relation. A composition wholly in the major chord, without any introduction of the so-called accidental, is simple, somewhat primitive and, to most people, a bit tiresome. A knowledge of the right time and the right way to use the accidental, or the unexpected idea, enables one to add the charm of subtlety and to increase the interest.

A room presents an admirable opportunity for the working out of this idea. The novice, or even the artist, should know the law and be able to obey it perfectly before he may break it. A deviation from the established form in any expression is the so-called poet's license, or artist's license, granted to the masters of the situation and not to the rank and file of the uninformed.

It is essential that harmony be accepted, not only as the desirable criterion, but also as the basic idea for all effective composition. Colour harmony, like harmony in sound, is based upon tonal relationships. There are generally conceded to be two kinds - those of likeness and those of contrast or difference. This likeness is sometimes called analogy or relationship or natural agreement. It may be illustrated with the colour green, which is a union of yellow and blue in equal force. Green is, therefore, as much related to yellow as to blue, and is one-half related to each. It is, therefore, somewhat harmonious with each from the outset.

Blue green is three parts blue and one part yellow, thus being in closer harmony with blue than with yellow. It may be used with yellow because it has one part at least in common, and is therefore related to it, though in the quality of harmony it is not so closely associated.

Yellow green, on the other hand, is more harmonious with yellow than with blue because of its component parts. Yellow, it will be seen, is a common element in yellow green, green, and blue green. Therefore, these four form what is known as a related or analogous harmony in colour. Any two, three, or the whole four selected in their proper values with right intensity relations become a colour harmony of the first kind or the likeness type. If yellow be considered with yellow orange, orange, and red orange, it forms a family relationship in which two, three, or four tones may form a group.

Normal yellow and normal red, or normal yellow and normal blue, are not related and may, therefore, not be considered together in any one of these groups. Yet if red is the standard colour chosen, red orange, orange, and yellow orange are each related to it, and a third analogous family is seen. If blue, blue green, green, and yellow green are chosen a fourth group appears.

Elevation Suggesting wall and furniture treatment for a simple dinning room in a country house

Elevation Suggesting wall and furniture treatment for a simple dinning-room in a country house; chintz and painted furniture. brilliant colours in small areas in soft gray background.

The same thing is true in the consideration of purples. Blue, blue purple, purple, and red purple form a group; red, red purple, purple, and blue purple form another group.

This method of producing a colour harmony is the simplest because the colour tones are themselves related in their inherent makeup. Even if two or more of them appear in quite intense tones, a concord or agreement in natural forces makes their harmonizing appear simpler, although it is in reality cruder, and it is generally very temperamental in its choice and use.

If one intuitively chooses schemes in house decoration in which blue, blue green, green and yellow green dominate, it is apt to be for temperamental or climatic reasons, or, perchance, because of too much light in the particular locality in which the problem is worked out. If the soft browns, tans, or buffs in the realm of red orange, orange, and yellow orange are selected, the same conditions of temperament or location probably influenced their choice.

The introduction of the complementary colour would necessarily bring in the three or four elements of colour possibility. The analogous scheme never presents this chance. With the analogous scheme, however, it is possible to introduce complementary small notes or areas which may be called the accidentals in the established colour scheme.

The second phase of colour harmony is known as complementary, this being harmony of contrast. Full intense complements are dissimilar in every particular. No part of yellow or its qualities is found in purple, no quality of blue in orange, nor of red in green. As full intense normal colours these are totally unrelated and are the most inharmonious possible colour tones when used next to each other without any separation by a neutral tone. Nothing can be cruder, harsher, or more commonplace than a rug in red and green. With these colour tones in juxtaposition it is impossible for the eye to accept the resulting condition, and every one knows the vibration or blurred effect produced by an attempt to accommodate the eye to such a colour combination.