Nitrate Of Potash

In Chapter VII (Gum - Gelatins). of this work, we have said all that is necessary of this substance. Before using, it must be perfectly dried. It colors the flame of alcohol clear pink.

Sulphuret Of Sodium

Dry the glauber salt, in an iron pan over a coal fire, as long as watery vapors arise from it; the white powder resulting is mixed with 1/3 its weight of powdered charcoal, placed in a crucible, covered, and exposed to the strongest heat of a stove. Sulphuret of sodium is produced, which fuses; when the crucible is taken from the fire it is allowed to cool, then broken, and the sulphuret powdered and preserved in well-stoppered bottles.

Oxalate Of Soda

Is prepared by neutralizing a concentrated hot solution of carbonate of soda, by slowly adding oxalic acid until it turns blue litmus paper into red. The salt is crystallized and dried in the usual manner, using cold water for washing, and no heat in drying.

Nitrate Of Baryta

The material to manufacture this salt is the native sulphate or carbonate of baryta, or the commercial chloride of barium. The mode of preparation for the two former is the same as that of the nitrate of strontia, as we shall see. From chloride of barium it is prepared as follows : Dissolve four parts of chloride of barium in eight of hot water, and three parts of nitrate of soda in three of hot water; mix the solution while hot, and stir till cold. Owing to chemical affinities, an exchange of acids and basis takes place, from which results a fine crystalliration of nitrate of baryta and chloride of sodium.

The nitrate of baryta is drained in a glass funnel from the mother liquor, washed slightly with cold water, then dissolved in hot water, and recovered by a second crystallization. The mother liquor from this latter yields another though more impure supply of the salt The crystals are treated in the same manner as nitrate of strontia.

Chlorate Of Baryta

This salt is difficult to prepare sufficiently pure for the wants of the pyrotechnist Its preparation is very circumstantial, and the best is as follows: Dissolve 15 parts of tar* taric acid in 48 parts of water, and neutralize by adding gradually 14 parts of crystallized carbonate of soda. At the same time have 12 parts of chlorate of potash dissolved in 32 of boiling water. The hot solutions are mixed, stirred up, and set aside to cool. On cooling, there will be found a precipitate of bitartrate of potash and a solution of chlorate of soda.

This latter is filtered off, and to it are added 12 parts of oxalic acid dissolved in 36 parts of cold water, the mixed solutions being surrounded with a frigorific mixture in an ice freezer. It is necessary for the precipitation of the oxalate of soda that the solutions should be kept as cold as is practicable, since this salt is quite soluble at the ordinary temperature. The oxalic acid has disengaged the chloric acid, which latter is now contained in the supernatant liquor, and after filtering, is in its turn neutralized with freshly precipitated pulpy carbonate of baryta, by the aid of a slight elevation of temperature. The solution of chlorate of baryta is then evaporated over a water bath, and the salt as it forms removed from the liquor which is completely dried. For the purpose of a pyrotechnic display, this salt must not be deliquescent, nor exhale any acid, and when ignited on paper must show a purely emerald light; if this light has a reddish or yellowish hue, the salt is unfit for use. The carbonate of baryta called for in this formula is prepared by precipitating a solution of chloride of barium by one of carbonate of ammonia, to which some ammonia has been added.

When the white precipitate has settled, pour off the supernatant liquid, bring the precipitate on a filter, and wash it with pure water as long as the washings carry off any ammonia, which is the case if it colors a drop of a dilute solution of blue vitriol a deeper blue.

Chloride Of Strontium

This is prepared in the same manner as the nitrate of strontia, substituting hydrochlorio acid for nitric acid. Owing to its greater solubility in water, it is necessary to obtain the salt crystallized to evaporate the solution to a less bulk before a crop of crystals will form. These are drained in the same way as the nitrate, but dried at a higher temperature on bricks, and preserved in well-stoppered bottles.