-The canvas being stretched on a frame, they give it a layer of size, or paste-water. When dry, they go over it with a pumice-stone, to smooth off the knots. By means of the size the little threads and hairs are all laid close on the cloth, and the little holes stopped up, so as no colour can pass through. When the cloth is dry, they lay on oker, which is a natural earth, and bears a body; sometimes mixing with it a little white lead, to make it dry the sooner. When dry, they go over it with the pumice-stone, to make it smooth. After this, they sometimes add a second layer composed of white lead, and a little charcoal black, to render the ground of an ash-colour; observing in each manner to lay on as little colour as possible; that the cloth may not break, and that the colours, when they come to be painted over, may preserve the better.,,In some Painting of Titian and Paolo Veronese, we find they made their ground with water, and painted over it with oil; which contributed much to the vivacity and freshness of their works: for the water ground, by imbibing the oil of the colours, leaves them the more beautiful; the oil itself taking away a deal of their vivacity. As little oil therefore is to be used as possible, if it be desired to have the colours keep fresh: for this reason some mix them with oil of aspic, which evaporates immediately, yet serves to make them manageable with the pencil. To paint on stones or metal, it is not necessary to apply size, as on cloth; it suffices to add a slight layer or colours, before you draw your design; nor even is this done, on stones, where it is desired the ground should appear, as on certain marbles of extraordinary colours.