It should not be broken into patches and neutralised by divisions, but used in large enough spaces to dominate, or bring into itself or its own influence all that is placed in the room.

If this rule is disregarded every piece of furniture unrelated to the whole becomes a spot, it has no real connection with the room, and the room itself, instead of a harmonious and delightful influence, akin to that of a sun-flushed dawn or a sunset sky, is like a picture where there is no composition, or a book where incident is jumbled together without relation to the story.
In short, placing of colour in large uniform masses used in gradation is the groundwork of all artistic effect in interiors.

As I have said, it is the same rule that governs pictures, the general tone may be green or blue, or a division of each, but to be a perfect and harmonious view, every detail must relate to one or both of these tints.
In formulating thus far the rules for use of colour in rooms, we have touched upon three principles which are equally binding in interiors, whether of a cottage or a palace; the first is that of colour in relation to light, the second of colour in gradation, and the third of colour in masses.
A house in which walls and ceilings are simply well coloured or covered, has advanced very far toward the home which is the rightful endowment of every human being.

The variations of treatment, which pertain to more costly houses, the application of design in borders and frieze spaces, walls, wainscots, and ceilings, are details which will probably call for artistic advice and professional knowledge, since in these things it is easy to err in misapplied decoration.

The advance from perfect simplicity to selected and beautiful ornament marks not only the degree of cost but of knowledge which it is in the power of the house-owner to command.