The heads of the Rockets should be placed on the opposite sides of the cross piece, and their ends on the same of the large rod; then their mouths must be connected by a leader, which, when they are fired, must be burned through the middle, and then they will exert their ascending forces at the same time.
Signal Rockets.
5. SIGNAL ROCKETS.
These are of two kinds, namely, those which have reports and those which have not. The first kind may be made somewhat longer in proportion than ordinary, by about one or two diameters, and on their charge must be driven a greater quantity of clay than usual; afterwards their bounce, choak, and cap, may be effected after the manner before described.
When of the second kind their cases and rods must be made very light; in other respects they are similar to the common sky-Rocket when without any appendages.
Both the first and latter kind are frequently fired in groups of six, eight, ten, &c; and considered as signals for the exhibition of pieces of greater magnitude.
When several of these are properly fixed to one rod, and fired together, they form in their flight a most beautiful appearance, for being so connected, their emissions will unite, and form a tail of stupendous magnitude, and the bursting of so many heads at once, will produce a grand explosion, not unlike (though less productive of injury) the bursting of a balloon in the atmosphere. When Rockets are arranged in this manner, particular care must be observed, in their filling and ramming, as well as in their exact uniformity of weight, else success is precarious. The rod also must be of proper dimensions, the length of the rods (according to the table) for eight-ounce Rockets, which is the best size for this purpose, is six feet six inches; then if four or six of these be fixed on one rod, the length of it must be about ten feet; in its circumference at top must be made as many grooves as there are to be Rockets, and of length to correspond. The rod must be sufficiently large at top, to admit the Rockets lying close in the grooves without pressing each other too tight.
The Rockets must be firmly attached to the rod, or they will be liable by their ascending force to disengage themselves from it; but to prevent which, the best method of fixing them is to let the rod run about two inches above the Rockets, which will be sufficient to form a shoulder or stop to each Rocket, the groove being discontinued such a distance from the end; when this is done, a little binding round the whole will make it all quite fast. The upper part of the rod may be rounded off in the form of a cone, or which will be much better, a cap may be pasted over the whole, which (from their meeting with less resistance) will cause them to ascend to a greater height. The Rocket being properly fixed, a quick-match is to be carried from one mouth to the other, which being burnt in the middle, will communicate immediately to the whole.
When fired they must be suspended through the rings, as taught in the early part of this article.