Take six or any number of sky rockets, of what size you please; then cut some strong pack-thread, into pieces of three or four yards long, and tie each end of these pieces to a rocket in this manner. Having tied one end of your pack-thread, round the body, of one rocket, and the other end to another; take a second piece of pack-thread and make one end of it fast to one of the rockets already tied, and the other end to a third rocket, so that all the rockets except the two outside ones will be fastened to two pieces of pack-thread; the length of thread, from one rocket to the other, may be what the maker pleases; but the rockets must be all of a size, and their heads filled with the same weight of stars, rains, &c.
Having thus done, fix in the mouth of each rocket, a leader of the same length; and, when you are going to fire them, hang them almost close together, then tie the ends of the leaders together, and prime them; this prime being fired, all the rockets will mount at the same time, and divide themselves as far as the firings will allow; which division they will keep, provided they are all rammed alike, and well made. These sort of rockets, are called by some, chained-rockets.
Of Signal Sky Rockets.
Signal-rockets are made of several sorts, according to the different signals intended to be given: but in Artificial Fireworks, two sorts are only made use of, which are one with reports, and the other without any thing, except the charge; but those for the use of the Navy and Army, are headed with stars, serpents, &c.——Rockets which are to be bounced, must have their cases made one and a half or two diameters longer, than the common proportion, and after they are filled, drive in a double quantity of clay, then bounce and pinch them, after the usual manner, and fix on each a cap.
Signal sky rockets without bounces, are nothing more than common sky rockets, closed and caped: rockets of this sort are very light, therefore do not require such heavy sticks as those with loaded heads, for which reason, you may cut one length of the rocket, off the stick, or else make them thinner.
Signal rockets with reports, are sometimes fired in small flights, and often both these and those without reports, are used, for a signal, to begin firing a collection of works; and occasionally, for many other purposes.
How to fix two or more Sky Rockets on one stick.
Two, three, or six sky rockets, fixed on one stick, and fired together, make a grand and beautiful appearance; for the tails of all will seem but as one of an immense size, and the breaking of so many heads at once, will resemble the bursting of an air ballóón; but the management of this device, requires a skilful hand; therefore for the encouragement of those who are fond of curious performances, I shall give such instructions, that, if well observed, even by those who have not made a great progress in this art, there will be no doubt, of the rockets having the desired effect.
Rockets for this purpose, must be made with the greatest exactness, all rammed by the same hand, in the same mould, and out of the one proportion of composition; and after they are filled and headed, must all be of the same weight; the stick must also be well made, (and proportioned) according to the following directions: first supposing your rockets to be half pounders, whose sticks are six feet six inches long, then if two, three, or six of these are to be fixed on one stick, let the length of it, be nine feet nine inches, then cut the top of it, into as many sides, as there are rockets, and let the length of each side be equal to the length of one of the rockets without its head; and in each side, cut a groove (as usual,) then from the grooves, plane it round, down to the bottom, where its thickness must be equal to half the top of the round part. As the thickness of these sort of sticks, cannot be exactly ascertained, I shall give a rule which generally answers, for any number of rockets above two: the rule is this; that the stick at top, must be thick enough when the grooves are cut, for all the rockets to lay, without pressing each other, though as near together as possible.
When only two rockets, are to be fixed on one stick, let the length of the stick be, according to the last given proportion, but shaped after the common method, and the breadth and thickness, double the dimensions, given in the table page, 94. The point of poise, must be in the usual place, (let the number of rockets be what they will): if sticks made by the above directions, should be too heavy, plane them thinner; and if too light, make them thicker; but always make them of the same length.