After your cloth is nailed on the frame, pass over it a coat of size; when dry, rub it over with a pounce stone, to eat off all the knobs: the first size is intended to lay down all the threads, and fill up all the small holes, to prevent the colour from passing through. When the cloth is dry lay on a coat of simple colour, which may not destroy the others; for example, brown red, which is a natural earth, full of substance and lasting. If mixed with a little white lead it will dry sooner. In grinding this colour, use nut or linseed oil, and it should be prepared to lay on as thin as possible. When this colour is dry, rub it again with the pounce stone, which renders it smoother: lay on another coat of white lead and charcoal black, to render the ground greyish, having care in putting on as little colour as possible, to prevent the cloth from cracking, and for the better preservation of the colours to be laid afterwards. We will observe, that if there was no ground laid on the canvass of a picture, previous to painting it, and if painted directly on the bare cloth without any preparation, the colours would appear much more to their advantage, and preserve their brightness much longer. Some of the first masters impregnate their canvass with water colours only, and paint afterwards in oil over that ground. This method renders pieces more lively and bright, because the ground in water colours draws and soaks the oil from the colours, rendering them finer; whereas, on the contrary, oil is the cause of their dulness, by its detention in their colours. It is desirable therefore, to use as little oil as possible; and in order to keep the colours stiff, mix with them a little of the oil of spike, which will evaporate very soon, but renders them more fluid and tractable in working.