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88 TESTING. The minerals soluble in water are either acids, or oxygen salts, or haloids. Their constituents are usually easily dis covered. Boracic and arsenious acids are almost the" only acids that occur. In testing the salts that belong to this group, one uses part of the solution for finding out the base, or electro-positive ingredient, and another part for finding out the electro-negative ingredient. The bases which occur in the mineral hydrolytes hitherto discovered are, ammonia, potash, soda, lime, magnesia, alumina, protoxide and peroxide of iron, oxides of zinc, copper, cobalt, uranium, and mercury. The electro-negative constituents are r omc, sulphuric, nitric, and boracic acids, and chlorine, i 16n a f lm< r ra l found to be insoluble in water, we must aeavour to dissolve it in hydrochloric or nitric acid. The latter is to be preferred when the appearance of the mineral, or f * mma ty experiments with the blowpipe, lead to the sup- p sition that it is a metallic alloy, a sulphide, or an arsenide, is manner the carbonates, phosphates, arseniates, chrom es, and many hydrous and anhydrous silicates, many sul- P i es, arsenides, and other metallic compounds, are decom pose and rendered soluble in water. The constituents of the o u ion thus obtained may then be determined by testin''-. Among the minerals which are not soluble either in water or mlf-,n nay enumerat ed sulphur, graphite, cinnabar, some ‘ . ® oxides, some sulphates, chromates, and fluorides; but specially silex, and a great number of silicates. These, as well as some other minerals that cannot be distinguished by the ow pipe, must be reduced to an extremely fine powder, melted in our times their weight of anhydrous carbonate of soda in a p a inum crucible, and thereby rendered soluble in hydrocliloric ci and water, and their solution examined further. n some cases, as when the mineral contains soda, it should be caES barytf^ * 8tr ° ngly with ^ tlmeS ^ Wci 8 ht of k ?° me m j nc ral aluminates, nearly infusible in carbonate of e readily decomposed by fusion with a mixture of of potash borate °f soda, or with anhydrous bisulphato Eon-metallic Elements and tlieir Compounds with Oxygen. end^thTwafw 1-611 i tbe aH8a / is ,leated in a tulj e closed at one the ’tube. * W en off > and is deposited at the cool end of theytre" b "7 lt ? S • def J a h r ™te on red-hot charcoal, when