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To Distingmish Genuine Silver

File or scrape the surface of the articles to be tested, rub the exposed portion on a touchstone and apply a test water consisting of 32 parts of distilled water and 16 parts of chromic acid. Rinse the stone in water and if the article is genuine silver a red spot will be left upon the stone, but if it is an imitation the mark will be unaffected. The finer the quality of the silver the more intense will be the red spot Silver Assay with Testing Tube. Place in the tube enough of the pulverized mineral to fill one inch of space, and on this pour nitric acid to occupy two inches more, and hold the mixture over the flame until the acid boils. The acid will dissolve whatever silver may be present, and must be passed through filtering paper to remove extraneous matter, and returned to the tube. Next add a few drops of water saturated with salt; any silver or lead that may be present will be precipitated in a cloudy form to the bottom. Drain off the acid, place the precipitate in the sunlight, and in a few minutes, if it contain silver, it will turn to a purple color, and may be again liquified by the addition of spirits of ammonia. The testing tube is formed of thin glass, about five inches long, and less than one inch diameter; bottom and sides of equal thickness. Where the tube is lacking, a cup may be used instead. Silver Assay by Smelting. If no lead is present, mix 600 grs. of the pulverized ore with 300 grs. carbonate of soda, 600 grs. of litharge, and 12 grains charcoal in a crucible; add a slight coal of borax over all, put on the furnace, melt, take off, give it a few taps to settle the metal, let it cool, and remove the button.