In this case, the idea of decoration is, to make the walls a barrier of colour only, instead of hard, unyielding masonry; to take away the sense of being shut in a box, and give instead freedom to thought and pleasure to the sense.
It is the effect of shut-in-ness which the square and rigid walls of a room give that makes drapery so effective and welcome, and which also gives value to the practice of covering walls with silks or other textiles.

The softened surface takes away the sense of restraint.

We hang our walls with pictures, or cover them with textiles, or with paper which carries design, or even colour them with pigments--something--anything, which will disguise a restraining bound, or make it masquerade as a luxury.
This effort or instinct has set in motion the machinery of the world.

It has created tapestries and brocades for castle and palace, and invented cheap substitutes for these costly products, so that the smallest and poorest house as well as the richest can cover its walls with something pleasant to the eye and suggestive to the mind.
[Illustration: LARGE SITTING-ROOM IN "STAR ROCK" COUNTRY HOUSE] It is one of the privileges and opportunities of art to invent these disguises; and to do it so thoroughly and successfully as to content us with facts which would otherwise be disagreeable.

And we do, by these various devices, make our walls so hospitable to our thoughts that we take positive and continual pleasure in them.
We do this chiefly, perhaps, by ministering to our instinctive love of colour; which to many temperaments is like food to the hungry, and satisfies as insistent a demand of the mind as food to the body.
At this late period of the world we are the inheritors of many methods of wall disguise, from the primitive weavings or blanket coverings with which nomadic peoples lined the walls of their tents, or the arras which in later days covered the roughness and rudeness of the stone walls of kings and barons, to the pictured tapestries of later centuries.