is done as follows: they stretch the canvas on a frame, and then give it a couch or lay of size; and when it is dry, they go over it with the pumice-stone, to smooth off the knots.,By means of this size, the little, threads and hair are all laid close on the cloth, and the little holes stopp'd up, so that 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 a little white-lead with it, to make it dry the sooner. When it is dry, they go over with the pumice-stone to make if smooth.,After this, sometimes a second couch is apply'd, compos'd of white-lead, and a little charcoal-black, to render the ground, of an ash-colour; but care is to be taken 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 be preserv'd the better.,In some of the paintings 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 ground, by imbibing the oil of the colours, leaves them the more beautiful; the oil itself, taking away a deal of their vivacity.,,