-When well dry, they give it two or three washes with boiling oil, till the plaister remain quite greasy, and will imbibe no more. Over this they apply desiccative or drying colours, viz. white chalk,red oker, or other chalks beaten pretty stiff. This layer being well dry, they sketch out, and design their subject; and at last paint it over; mixing a little varnish with their colours, to save the varnishing afterwards. Others, to fortify their wall better against moisture, cover it with a plaister of lime, marble-dust, or a cement made of beaten tiles soaked with linseed oil; and at last prepare a composition of Greek pitch, mastich, and thick varnish boiled together, which they apply hot over the former plaister: when dry, they lay on the colours as before. Others, in fine, make their plaister with lime-mortar, tile-cement and iron scum; which being well beaten and incorporated with white of eggs and linseed oil, makes an excellent plaister. When dry the colours are applied as before.