Or ceruse, and other white oxides of lead, under the various denominations of London and Nottingham whites, &c., flake white, Crems or Cremnitz white, Roman and Venetian whites, Blanc d'argent or silver white, sulphate of lead, Antwerp white, &c. The heaviest and whitest of these are the best, and in point of colour and body are superior to all other whites. They are all, when pure and properly applied in oil and varnish, safe and durable, and dry well without addition; but excess of oil discolours them, and in water-painting they are changeable even to blackness. They have also a destructive effect upon all vegetal lakes, except the madder lakes, and madder carmines; they are equally injurious to red and orange leads or minium, king's and patent yellow, massicot, gamboge, orpiments, &c.: but ultramarine, red and orange vermillions, yellow and orange chromes, madder colours, sienna earth, Indian red, and all the ochres, compound with these whites with little or no injury. In oil painting white lead is essential in the ground, in dead colouring, in the formation of tints of all colours, and in scumbling, either alone or mixed with all other pigments. It is also the best local white when neutralized with black, but must not be employed in water-colour painting, distemper, crayon painting, or fresco, nor with any pigment having an inflammable basis, or liable to be destroyed by fire: for with all such they occasion change of colour, either by becoming dark themselves, or by fading the colours they are mixed with. Cleanliness in using these pigments is necessary for health; for though not virulently poisonous, they are pernicious when taken into or imbibed by the pores or otherwise, as are all other pigments of which lead is the basis.