If the room is large and a few chairs and benches are admitted, they should be of wood, plain and for service alone, as becomes a room that is arranged but for one purpose,--namely, the exhibition of certain pictures,--and they should be painted or stained in tone to correspond with the room. The light should be under absolute control, and kept quite soft, diffused, and constant throughout the day. The room should be closed at night, or at least the people fully warned by notices in catalogue and elsewhere that if they have any real desire to see and understand the pictures they will come during the day. The pictures should be well spaced, so that each may, to a certain degree, be studied by itself, for each is as complete a work as a piece of music. In short, in an exhibition of pictures, or of anything else, everything should be subordinated to the things exhibited; nothing should be permitted to obtrude upon the attention to their disadvantage; the work of the decorator and furnisher on such an occasion is perfect when it is unnoticed. For black-and-whites, experiments in color may be made, but for paintings which are compositions in color the background should be neutral,--silent like the background of music. As every one knows, green and red, side by side, accentuate and help each other; therefore, pictures in which the prevailing tone is green are helped by a red or crimson background, while pictures in which the prevailing tone is red are helped by a green background. The foregoing is elementary and a matter of common observation, and the walls of art galleries and exhibitions are frequently covered with either a shade of green or a shade of crimson; but in placing pictures no discrimination is exercised,--landscapes and marines in which green predominates are placed side by side with portraits and interiors in which red frequently predominates on the same green or red background, to the advantage of one set of pictures and the detriment of the other. So far as color-effect is concerned, the pictures themselves go very well side by side, the red of the life pieces helping the green of the nature pieces, and _vice versa_; but if the background is permitted to assert itself, if the pictures are spaced on the wall, any background which accentuates the one class does so at the expense of the other. If pictures in which the prevailing tone is green are to be placed on the same wall with pictures in which red predominates, the background should be neither red nor green, but, theoretically, a gray, which is neutral and helps all colors in contrast; practically, however, a grayish hue of brown, because pure gray requires a greater expanse of wall between each picture than the exigencies of an exhibition or of a typical picture gallery permit, while the element of brown permits the wall to assert itself a little more positively between the frames, and, at the same time, the quality of neutrality is almost as well preserved.