NITRATE OF STRONTTAN.--The effect of this salt, lately introduced into ornamental pyrotechny, is to pro duce a fine crimson light; nor is it too expensive, con sidering that it gives a colour so beautiful, and hitherto unknown in this art.
AeconoL.—Spirit of wine is recommended for many compositions, on the futile notion of adding to their in flammability. As it necessarily evaporates, it can pro duce no such effect. It is also recommended for tem pering gunpowder for quick-match, as it does not per mit the nitre to crystallize and separate from the other ingredients. This object may however be attained well enough with water, so that it may be considered as an unnecessary expense. Vinegar has also been recom mended for the same purposes; but it is of very little use in this point of view, and may also be dispensed with.
As it is of use to know what to avoid as well as to adopt from the various books, which no one is inclined to distrust from the positive manner in which the ef fects of these substances are spoken of, we shall continue the enumeration of these matters, merely for the pur pose of condemning them. We shall, in this manner, save the artists from much labour, expense, and disap pointment. With respect to many of them, the uses are absolutely imaginary ; and of others, from their palpable absurdity, we can only think that they must have been recommended for the sole purpose of blind ing or misleading those who trust to these receipts. \Ve shall have occasion again hereafter, in examining the directions given for making many compositions, to see that they are either impracticable or absurd, or incapa ble of answering the ends proposed. We can only therefore conclude, either that the authors of these books are entirely ignorant of their subjects, or else that their designs were to maintain secrets which they considered valuable, while they professed to disclose them. To clear out all this rubbish, we consider even
more necessary than to describe how the required ob jects may be attained ; nor without such an explana tion and examination, indeed, would our readers be able to comprehend why we had varied so much from our predecessors, and to whom credit ought to be given. The assignment of reasons, and the sort of criticism we shall here use, will enable the readers of this article to judge what is right on this subject, from principles. The work of Captain Jones, so called, the chief reposi tory of these impracticable and false receipts, will be among the principal ones to be thus examined, because it is the standard book. The artificers in fireworks, however, as well as ourselves, know pretty well where its faults lie, though still misled by it in many parti culars.
is recommended as an ingredient in fireworks for the purpose of producing a perfume. It is converted into "flour," as the receipt says, by putting it into an earthen pot, which is to be covered with paper, and then exposed to the fire. This flour is to be returned into the pot, and treated in the same way till it is perfectly white and fine. It is evident that this is a bad method of procuring benzoic acid, which may be obtained mach cheaper from the drug gists, vete it of any use. But in the burning of a fire wo•k this substance is not evaporated but destroyed, and consequently it can yield no perfume. An imagi nary perlumed oil of Benzoin is also recommended for wet compositions for the same end, when there is no such thing known.
OIL OF SP1KE.—This is an expensive essential oil, all the purposes of which may be served by the oil of turpentine ; but in fact none of these essential oils are required for ornamental fireworks. To say the least of them, they are useless.