Alutation Pieces.
It is a necessary system in all fireworks, to produce successive changes, and particularly on the large scale, when it is intended to continue an exhibition for some hours perhaps. On a small scale, it is also required ; but in such cases, the changes arc commonly limited to three or four, as they are generally all accomplished within the course of a quarter of an hour. The books contain many projects of this kind, even on the small scale : while they also pretend to perform ten or twelve mutations in one piece, and that, not only in a fixed but in a moving one. We have no hesitation in saying, that this is impossible, and that many of the drawings which have been given for this purpose cannot be exe cuted. It is not possible to unite so many discordant parts, which are all to move, in any manner, so that they shall act properly. The weight becomes as un manageable as the complication ; so that the parts are brought to a state of rest, or else they confuse each other in the effect, or lastly, some of them take fire be fore their time, from the difficulty of keeping so many leaders safe and separate. Besides, it must be recol lected that no wheel will set fire to any thing else ; so that whenever a firework of this kind comes into the series of changes, the operator must be always on the watch, net only to light a fresh leader, but to take care that he does not mistake one for another.
Nor is there any advantage in thus combining pieces We do not think it necessary to make a separate head for this article, as is commonly done; since, for the most part, these differ in no respect from fireworks burnt on the land.
We have already treated particularly of the common water rocket ; and have also, under the different heads of wheels and exploding pots, shown how they may be together in this intricate manner, as all that is gained by it, even when it succeeds, is to exhibit a fresh piece in the same place ; whereas the effect is as good if it be done at one side, or above, or below, which it may easily be on a separate framework, and with a distinct arrange ment of leaders. We therefore dissuade our readers
from these attempts, and recommend them to limit their mutations for moving fireworks, to two or three, and for the smaller kinds of fixed ones to three or four, or at most five.
As we have now, under the preceding heads, shown how the pieces for which we have given plans may be fixed, either all at once or according to an order of two, or three, or more successions, we shall not here give any further drawings of that nature, as it would re quire more plates than are compatible with the neces sary extent of this article. On reconsidering the designs that have been given, an artist will see that there is scarcely one of them that will not admit of two or three changes more than We have represented, but which we omitted, that we might not encumber and confuse the drawings. We do not, therefore, think it necessary to give any more of these for that purpose, but shall con tent ourselves with giving two sets of drawings, one of merely ornamental fires, and the other of architectu ral constructions, as specimens of what may be done in this way.
The drawings,(Plate CCCCLXXV. Figs. 1-20,) in deed, so far explain themselves, that scarcely any other remarks are necessary beyond those which we have al ready made. But we must observe respecting the first, that although we have given twelve changes for a circu lar figure, all the fires required for them cannot be at tached to one frame, for want of room. These are rather intended as specimens of what may be done in this way, than as a recommendation to be followed. The artist may select any four or six, according to his taste ; and he will even find these abundantly difficult to manage on one frame. If the whole should, however, be required to appear in the same place, separate frames should be provided, and so adapted that the front one may easily be removed, to expose that behind it.