otherwise called azure, is one of the primitive colours of the rays of light. See OPTICS.

Painters Blue is made different according to the different kinds of painting. In limning, fresco, and miniature, they use indifferently ultramarine, blue-ashes, and smalt: These are their natural blues, excepting the last, which is partly natural, and partly artificial.

In oil and miniature, they also use indigo prepared; as also a fictitious ultramarine. See ULTRAMARINE and INDIGO.

Enamellers, and painters upon glass, have also blues proper to themselves, each preparing them after their own manner.

Turnsole Blue is used in painting on wood, and is made of the seed of the turnsole: The way of preparing it is, to boil four ounces of turnsole in a pint and half of water in which lime has been slackened.

Flanders Blue is a colour bordering on green, and seldom used but in landscapes. To write on paper or parchment with Blue ink. Grind Blue-Japan. Take gum-water, what quantity you please, and white lead a sufficient quantity; grind them well upon a porphyry; then take ifinglats size what quantity you please, of the finest and best flint a sufficient quantity, mix them well; to which add, of your white lead, before ground, so much as may give it a sufficient body; mix all these together to the consistence of a paint.

Blue-bottle, in botany. See Cyanus.

Blue-cap, in ichthyology: See Salmo.

Blue-mantle, in heraldry, the title of a poursuivant at arms.

Bluff-head, among sailors. A ship is said to be bluff-headed, that has an upright stern.

Blunderbuss, a short fire-arm with a wide bore, capable of holding a number of bullets at once.

Blushing, a suffusion, or redness of the cheeks, excited by a sense of shame, on account of a consciousness of some failing or imperfection.