Nitrate Of Strontia

This salt is prepared from the native sulphate of strontia or its carbonate; the latter 13 furnishes a solution of the nitrate when it is powdered, placed in a porcelain dish, and treated with commercial nitric acid as long as a violent effervescence is produced, then placing the dish on a sand bath, and heating it slowly, when a small portion of the mineral must remain behind, or otherwise it has to be added in order to prevent a loss of acid. The hot solution is then filtered and allowed to cool, when a second crop of crystals will result. Both crops are then drained on a glass funnel, folded in blotting paper, and pressed between two bricks. They are next ground into powder in a porcelain mortar, dried upon warm bricks, and finally preserved in well-stopped bottles. The sulphate of strontia requires another manipulation, which consists in first calcining the powdered mineral, embodied with about two-fifths of its weight of flour, and made into paste with some fatty oil, in crucibles or earthen pots, which are placed in a brick or potter's kiln. This yields an impure sulphuret of strontium, which is exhausted with hot water; the solution filtered and evaporated to the point of crystallization. The crystals, which are generally indistinct, may be separated, drained, and dried upon bricks, if it is desired to preserve them. To convert the concentrated solution into nitrate, it is treated with nitric acid diluted with an equal weight of water. This operation involves the disengagement of large quantities of sulphuretted hydrogen, and renders it necessary to perform it in the open air or under a good draught. When the effervescence has ceased, a small excess of sulphuret of strontium is added, the solution of the now nitrate of strontia is heated over a sand bath, filtered, and treated as above.

Oxalate Of Strontia

Add to a solution of nitrate or chloride, a solution of oxalic acid as long as a white precipitate is formed. This is filtered off and repeatedly washed with water, then dried as usual. The acid liquor from the precipitation, as well as the washings, contains some strontia which ought to be recovered by precipitation with carbonate of ammonia, and the carbonate of strontia formed converted into nitrate or chloride.

Sulphuret Of Tin

Tin is filed into a coarse powder, and mixed with an equal weight of flowers of sulphur. This mixture is deflagrated in a crucible brought to and kept at a red heat on a coal fire. Small portions are introduced at a time, when deflagration takes place, caused by the combustion of the excess of sulphur; no more is added until what is left in the crucible has assumed the temperature of the crucible, and is in a glow. When the crucible is about 3/4 full, it is covered, heated somewhat stronger for a while, and then allowed to cool. The contents of the crucible are powdered in an iron mortar; if any of the metal should still be present in a free state, proved by the flattening of some of the coarser grains, they must either be picked out, or the whole calcination must be renewed after adding some sulphur.

Nitrate Of Copper

Copper turnings or small slips of copper, together with a sufficient proportion of nitric acid in a porcelain dish, are placed in the open air and slightly heated. Should all the copper be dissolved, some more must be added until it ceases to dissolve, whereupon the solution is heated to boiling, then taken from the fire and allowed to cool slowly. The nitrate of copper will form in fine green crystals, which are freed from the mother liquor by pressing between filtering paper, and drying on bricks without heat. They are preserved in glass stopped bottles.

Chloride Of Copper

Is prepared in the same manner with aqua regia instead of nitric acid. The solution is rapidly boiled down, and the blue crystals of chloride of copper which form on cooling when drained from the mother liquor, but still moist, are dissolved in alcohol, partly on account of their deliquescence, and because this prepara-tion is only used in that condition.

Iodide Of Copper

A solution of sulphate of copper, saturated in the cold, is added to a similar one of iodide of potassium until the liquid shows a blue color, when the precipitate has settled. The whole is then well stirred, filtered, and the precipitate on the filter washed, first with water, then with alcohol. The brownish white powder of iodide of copper is dried upon bricks at a low heat, and when dried preserved in stoppered bottles.

We have thus far enlarged upon the preparation of the rarer compounds required for pyrotechnic displays, all other ingredients are easily obtained in the trade, but they must always be of the best quality.