Priming you make of any colour that hath a body; as whitelead, brown or red oker, and umber, ground in oyl pretty light: but the painters have the best conveniency for this composition; for tis made of the scraping of their pots, the oldest skinny colours, and the cleansing or filth of their pencils. All these being mixed grind very well, put them into a canvas-bag that will hold a pint, sowed very strongly for this purpose. If the colour be too dark, it may be alter'd by adding a little white-lead. Being securely inclosed and tied up, press it between a pair of screws, such as apothecaries employ, now and then turning the bag, until all the fine primer be squeezed out, which should be received into a gallipot, the skins and filth that remain are useless, and may therefore be thrown away. With this your piece must be very thinly primed over, and permitted to drie.,,,