The subject of grounds is of the greatest importance to the future of the picture. Many of our finest works are suffering from want of due care in their preparation. If on canvas, it is essential that the ground, though firm and hard, should have due toughness and flexibility; to which end it should be thin, and have sufficient oil in its composition, and, whether on canvas or panel, just such an amount of absorbency as will admit of the proper union of the picture with it. If too absorbent, it is troublesome to the painter, and apt to make the picture heavy in the darks, while it prevents, in a degree, the use of the ground as a source of illumination to pigment used over it transparently. If too hard and impervious, the picture is apt to divide from it and blister off. This is often the case with Turner's pictures. "The Regatta at Cowes," and the "Fishing Boats at Yarmouth," in the Sheepshanks' collection, have both a strong tendency to rise from the ground; as have also many other of his works, such as "Pope's Villa at Twickenham," the "Mercury and Herse," "the Beach at Hastings," besides many in the national collection, all which require great care on this account. The finest landscape by Calcott, "Southampton Water," the property of Mr. Gibbs, has suffered largely, and is likely to suffer from this cause; indeed it is a source of evil to many other English paintings of the period. Pictures thus endangered should, if the size permits, be covered with glass in front, and, at any rate, lined behind with painted cloth, to render them impervious to the damp; and they should be kept away from the wall against which they are hung by small blockes of cork at the four corners.,Reynolds's works are some of them liable to suffer from this cause, more especially those most free from the injurious use of asphaltum. Moreover, he was careless in overloading his pictures, repeating his work over and over again when dissatisfied with his previous labours, thus losing the benefit of a pure ground.