Facts About Gold

Pure gold is so soft that it would soon be worn away by use and it is alvvays alloyed with a varying proportion oí copper or süver, usually about onetenth. Pure sold is said tobe 24carats. Thus, 18-carat ffold containa IS parts of the pure metal in 4. or, is three-quarters pure. !any elieap alloys of base metáis can be male whieh v?ry strongly reaemble gold n colur and luster; but, in the absence of a complete chemical test, the high specific gravity of gold ÍÍ9.3) is the best test of its purity, though this has been ingeniously imitated by covering tlio heavy butcheaper 'aaetal, platinum, with a layor of gold. ïffan pyrites and other yellowish minerndls are constantly be ng mistaken for 'AL, by inexporienoed persons, much ta Vbtír aisappointtnent, buta very simple test will show whether a doubtful specimen is really the true metal. Gold is Tery cctik - that is, it can be cut and shaved with a knife, liko a piece of wood or horn; while pyrites and other worthless minerals will crumblo under "4h knife-blade like a lump of sugar. TL any reader of this article ever finds a yellowish mineral which can be cut without crumbling, it is worth a more thorough test; otherwise he may as well save himself unneoessary trouble and disappointment Very few Chemicals isave any effect on gold. Selenic acid will dissolve it, but few chomists have Over seen this very rare substance. A mixture of nitric and hydrochloric acida (aqua regia) will also dissolve it, form■íng a chloride of gold; and so will a solui of chlorine gas ín water. In both Miiese Iiquid3 a peculiarly active form of chlorine, known asaacerechlorino, is present, which probably unites directly with the metal. Gold, like all the noble -metáis, is uncbanged by heating in the ■air. lts oxides can bo obtained by "Chemical reactions, but they are very "anstablo, and easlly reduced back to the metal. The chloride r.bove referred to is the only salt of any practical importance, and is used to produce the 'beautiful Purple of Cassius, a compound of tin and gtld of uncertain composition, but yielding magnificent ruby color when melted into glass. A hundredth of a grain of gold will deeply olor a cublc inch of glass. The most extensivo use ot tlie cnioride is, bowever, in photography, whero it is used to "tone" or color prints on silvered paper. This d;r ceninsr of the prints is due to the decomposition of the salt and the depos;tion in the picture of finely-divided metallic gold, which not only gives it the desired color, but renders the imago very permanent Hy beating out between pieces of membrane, gold may be formed into leaves of such thinness that 2S2.000 of them will only make a pile ono inch in height A single ounce of gold may tuus be spread over one hundred square feet. In the manufacture of gold toread for embroidery, a cylinder of silver is coverod with gold and afterwards drawn out into wire. In thisway six ounces of gold have been made to yield over two hundred miles of gilt wire. Even at this extreme tenuity the coating is perfect, and does not rust or tarnish. - Popular Science News. - "Yes," said the old hen, as sh picked her feathers, "every thing is chsnging. " "What's the trouble?" asked the peafowl. "These incubators. Seventy-flve chickens came walking out last night, and I can't teil which ars mine and whxh are the incubator's. Waternity is truly an awful rcsponsi bility."