The pictures of the Italian school at the time of Raffaelle had the grounds composed of pipe-clay, highly burned and finely pounded, mixed with a proportion of chalk, and formed into a substance with boiled parchment, or the skins of fish. Velasquez and Murillo painted their pictures upon the red earthy preparations with which the Spanish canvas has almost uniformly been charged. The ground of the pictures painted by Claude has frequently been prepared with an impression of chalk or pipe-clay, as was used by the old masters; the consequence is that the skies, distances, and delicate passages remain as clear as the day they were painted. The grounds of many of the pictures painted by Nicolo Poussin is, on the contrary, a dark brown, or red, prepared of a red earth, which in some instances has made the shadows opaque, and has even caused them to perish, an evil which is to be met with in several of the most beautiful and classical compositions of that master. William Vandevelde also painted on these kind of preparations. Some remarks on the dangers to be avoided in treating pictures of this description will be found in their proper places.,,