Raphael's picture of "The Vision of a Knight" is another example of the fearlessness of that artist in putting in or backing up his figures with a large amount of landscape background. The proportions of Correggio's "Venus, Mercury, and Cupid," are as nearly as possible those of a carte-de-visite enlarged; and that picture has no sky in the background, but a very suitable dark, cool, rocky scene, well subdued, for the rocks are quite near to the figures. This background gives wonderful brilliancy to the figures, and contrasts admirably with the warm and delicate flesh tints. Correggio's "Holy Family" has a landscape and architectural background, with a very little sky visible in the right-hand corner. In the "Judgment of Paris," by Rubens, the horizontal line of the background cuts the waist of the first female figure, showing that the artist was seated. The other two female figures are placed against a background of rocks and dark masses of foliage. Rubens' picture of the "Holy Family and St. George" is also a good example of the kind of picture for the photographer to study as to the situation of the horizontal line. The picture of "The Idle Servant," by Nicolaes Maes, is also an excellent subject for study of this kind. It shows the due relation of the horizon of an interior in a very marked degree, and its shape and subject are very suitable to the size and form of a carte-de-visite. So are his pictures of "The Cradle" and "A Dutch Housewife." The picture of "John Arnolfini of Lucca and his Wife," painted by John Van Eyck in the fifteenth century, is an excellent specimen of an interior background, with a peep out of a window on one side of the room. This is a capital subject for the study of photographers who wish to use a background representing an interior. "The Holy Family at a Fountain," a picture of the Dutch school, painted by Schoorel in the sixteenth century, has an elaborate landscape background with the horizon above the heads of the figures, as if the artist had been standing and the models sitting. For an example of a portrait less than half-length, with a landscape background, look at the portrait of "An Italian Gentleman," by Andrea da Solario. This picture shows how very conscientiously the old masters worked up to the truth of nature in representing the right amount of landscape in proportion to the figure; but the background is much too hard and carefully worked out to be pleasing. Besides, it is very destructive to the force and power of the picture, which will be at once visible on going to the portraits by Rembrandt, which have a marvellous power, and seem to stand right before the dark atmospheric backgrounds which that artist generally painted in his portraits.