With phosphorus and sulphur, zinc also combines, and with the latter, it forms the native sulphuret, known by the name of blende. It unites, also, with acids, and forms salts. Of these, the sulphate of zinc, or white vitriol, is the most common. It unites with various metals, forming alloys. Of these, that with copper, called brass, is the most known. Zinc, with copper, forms galvanic batteries. With tin and mercury, it constitutes amalgam for electrical machines. It forms, besides brass, the yellow copper, or laiton; commonly called pinchbeck. Acetic acid readily dissolves zinc. The acetate formed is not altered by exposure to the air, is soluble in water, and burns with a _blue_ flame. It may be used, therefore, in fire-works, to communicate that colour to flame. It may be formed very expeditiously, by mixing about equal parts of sulphate of zinc, and acetate of lead, both being in solution. The sulphate of lead, which is formed, will precipitate, and acetate of zinc remain in solution. By evaporation, it is obtained in crystals. This salt cannot injure any composition of fire-work, in which it enters; as it does not deliquesce, and, for that reason, may be advantageously employed. When zinc is used in fire-works, it should be remarkably fine. The powder may be very readily formed, by heating it, until it is about to fuse, and pulverizing it while hot, in a warm mortar. It is generally considered, however, that the best method of obtaining the powder of zinc, although a longer time is required, is by filing it; but the filings are more or less coarse, according to the file which is used. They may be sifted, and thus obtained of any degree of fineness. In various blue lights, in the blue flame of the parasol and cascades, and other descriptions of fire-works, it is used. It gives a more brilliant light than any other substance used for this purpose. It is frequently mixed with other substances; but, as to its peculiar properties, they remain the same. By the combustion of zinc, which follows in fire-works, it always produces an oxide. In this state, it is expelled, or thrown off. Acetate of zinc appears to possess advantages over zinc-filing, especially as it produces the same colour, may be more readily mixed, and with more accuracy, and does not deliquesce or absorb moisture, a circumstance which must always be guarded against in artificial fire-works. _Sec. XLIII. Of Brass._ This is a mixed metal, composed of copper and zinc. This alloy, according to the proportion of the metals, is more or less yellow, or reddish-yellow. The yellow copper, or _laiton_ of the French, the similor, Manheim gold, prince Rupert's metal, &c. are alloys of the same metals.