AZURE BLUE is a pigment prepared by mixing 2 parts of deep blue, 1 of oxide of zinc, and 4 of lead glass; the latter consisting of 4 parts of minium and 1 of sand. The above azure blue is for skies, but a pigment for more general use is prepared from 11 fused boraz and 67 gray flux; the latter being itself made from 89 pebble flux, 75 minima, and 25 sand.—BERLIN BLUE. See PRUSSIAN BLUE.—BitrxswicK BLUE, or is made by precipitating the alumina from a solution of alum by carbonate of soda, washing the precipitate. and adding sulphate of baryta, sulphate of iron, yellow prussiate of potash, and some bichromate of potash. When dried, this mixture is known as Brunswick blue, but when the sulphate of baryta is left out, and the material not dried. ;•. is called damp BLUE is a color used in pottery. and consists of 79 parts of gray flux. 7 carbonate of cobalt, 14 hydrated carbonate.—BratE COLOR OF FLOWERS, or anthoeyan, may be obtained from those petals of flowers which are blue by digesting them in spirits of wine in the dark. The color is, soluble in alcohol, but is precipitated front its alcoholic solution by water. it is changed to red by acids, and to green by alludies.—BLUE Corrgicas, or the sulphate of copper. See COPPER.—Bium DYES. See INDIGO, LITMUS. PRUSSIAN BLUE, and DYEINO.—IRON EARTH BLUE occurs native amongst bog iron ore and in mossy districts in Europe and New Zealand. It
mainly consists of a phosphate of iron with a little alumina, silica, and water. It is called natire Prussian blue.—INDIGO BLUE, in pottery-ware, consists of 13 parts of car bonate of cobalt, 26 hydrated carbonate of zinc, and 61 gray MIL—COBALT BLrE is the only really good and serviceable blue in the coloring of glass and porcelain, and is esen tially the oxide of cobalt (CoO), the coloring part of which Is so great, that the addition of part to white glass is sufficient to render it blue. Several of the compounds named above owe their blue color to this' substance. See CouALT.—DEEP BLUE is employed ha porcelain coloring, and is made from 1 part of oxide of cobalt, 4 glass of lead (2 minium, 1 white sand), 1 lead glass (2 minium, I sand, 1 calcined borax), and 1 oxide of zinc. all of which are placed together in a porcclaiu crucible, fused for 2 or 3 hours; the residue washed, dried, and ground to a fine powder.—Kixo's Bi.us as made from 29 parts carbonate of cobalt, 29 sand, and 42 carbonate of potash, by fusing these ingredients in a crucible. The residue is intense deep blue, bordering on a black blue, and is generally reduced to powder, and re-fused with about half its weight of pebble flux (3 ‘minium or litharge, and 1 sand).--alimntali BLUE and P.kRIS BLUE. See PRUSSIAN BLUE.