SECTION XVI, WHITES AND REDS. PERFUMERY, which is so fecund in odoriferous products, has been unable yet to manufacture harmless whites. Generally the whites it produces are more or less dangerous to the health. Indeed, salts of lead, bismuth, baryta, or zinc, are always the basis of these whites, and it would be a great improvement to produce a white as fine as those already in use, yet free from all those noxious properties. It is not the same for the reds; perfumery uses several kinds which all belong to the vegetable kingdom, such as the carthamine, garancine, carmine, geranium, etc., all of which are perfectly harmless. A METAL of a reddish-white color, very brittle, easy to powder, of a lamellous texture. Its specific gravity equals 9.83. It melts at 399°.2, and by cooling crystallizes in cubes disposed in such a manner that they form a quadrangular pyramid. Its nitric solution is used to make a sympathetic ink, nearly colorless by itself, but which becomes immediately black by contact with sulphuretted hydrogen; this solution is used to prepare pearl white. The perfumer ought to purchase the metal in well-defined crystals, so as to have it perfectly free from arsenic. Its use is dangerous. Pearl White in Trochists. Pure bismuth Nitric acid. 1 pound. 6 pounds. Reduce the bismuth to a coarse powder, and intro duce it into a porcelain dish with the nitric acid; and when the reaction has ceased, heat it gently until all the metal is dissolved; evaporate the solution to two-thirds, and pour it slowly into fifty times its volume of water. A white substance is precipitated, which is the subnitrate of bismuth, or white of pearl. Wash this white with water until it is free from acid; collect it on a cotton cloth, let it drain, and dry it with a gentle heat in a dark room. Liquid Pearl White. Subnitrate of bismuth Distilled water 1 pound. 3 pounds. Rub the subnitrate in a marble mortar, add the water little by little, and, when the mass is well mixed, introduce it into bottles of green glass. Unctuous White in Pomade. also called subcarbonate of lead, is a combination of carbonic acid and oxide of lead. It is white, friable, insipid, and insoluble in water. When pure, it completely dissolves in nitric acid. Ceruse is sold in the form of conical cakes weighing from two to four pounds. It is often mixed with other white substances of less value, such as sulphates of lead and baryta, chalk, plaster, etc. Ceruse is extensively used in the arts. Perfumers employ it in the composition of some whites. It is one of the most dangerous substances. Its use ought to be rejected. In some cases it has produced poisoning. Silver White. This white has sometimes been designated by the name of snow white. It is pure carbonate of lead. It may be prepared as a liquid in the same manner as the pearl white. A preparation is sold which is made in the following manner :— This white is composed in two bottles. The first contains a filtered solution of acetate of lead; the second, a weak solution of carbonate of soda in rose water. To use it, fill a wineglass with the liquid of the first bottle; then pour into it two spoonfuls of the liquid of the second bottle. Immediately a very fine white powder of carbonate of lead is precipitated, with which the skin is painted. Grind, adding the water little by little. When a homogeneous liquor is obtained, pour into bottles. White of Talc. Powdered tale 1 pound. Distilled vinegar 3 pounds. Pour the tale and the vinegar into a glass balloon, and digest for two weeks, shaking several times a day. Filter and wash the deposit until the water is no longer acid, squeeze it in a white cloth, throw the talc into a marble mortar, and grind it with a little soap water slightly gummy. When the whole is reduced into a paste, fill little porcelain jars, and let it dry. Make the mixture in a mortar with filtered water, and then pour into vials. |