CHAPTER VII.
OF ROCKETS AND THEIR APPENDAGES.
A rocket is a flying fusée, (_Fusées Volantes_ of the French), formed with paper, of a cylindrical shape, and filled with a composition of certain inflammable substances, being pierced in the diameter of its length. It is furnished with a stick, serving as a counter-weight, or balance, to guide it vertically in its ascension. It carries generally different garnishes, or furniture; as stars, serpents, fire-rains, marrons, meteors &c. which are thrown off, and produce an elegant appearance, when it terminates its flight.
Rockets have been applied to several uses. Thus, the war-rocket, as an incendiary, improved by Congreve, and the signal rocket, are some of its applications. These, however, are modified for the purpose, and will be spoken of hereafter. The Indian rockets, called Fougette (_Baguette à feu_ of the French) will also be noticed.
Although as a fire-work for exhibition, the rocket may be considered the most grand, and, especially when furnished with various decorations, the most brilliant, yet its utility for Military and Naval purposes is acknowledged by all.
When treating of sundry preliminary operations in the second part of this work, we had occasion to introduce the subject of rockets, as respects the formation of their cases, the manner of charging and driving them, with the tools required, and the boring of rockets, when they have been driven solid. These subjects may be found in sections iv, v, and viii. We purpose, however, to make such observations as may, with the remarks heretofore offered, furnish the reader with a general knowledge of the making, decorating, and discharging of rockets. On the theory of the ascension of rockets, motion of fire-wheels, &c. and observations on the rocket principle, consult the chapter in the first part of the work, concerning the theory of particular fire-works. For the manner of uniting sheets of paper of several thicknesses, for cases, see _Pasteboard_.
_Sec. I. Of the Caliber and Proportion of Rockets._
Sky-rockets are generally made of seven calibers, from half an inch to three inches. Different opinions have been entertained respecting the proper proportions. Some contend that the height should be always regulated by their exterior diameter. On this subject, several experiments, it seems, have been made by an experienced artist, M. Morel, not only to determine the length, which is best calculated to produce the maximum of ascension, but also with respect to the length compared with the caliber of the case.
The following tables are necessary in the formation of rockets. The first shows the size of the caliber of the mould, for rockets of a pound weight, and below; and the second points out the size required for the caliber of moulds, from one pound to fifty pounds. A lb. rocket, it must be observed, is that which is just capable of admitting a leaden bullet of a pound weight, and so of the rest.
_TABLE_ I. _Size of the caliber of moulds of a pound weight, and below to an ounce._
+----------+----------+ |Weight of | | |Rockets in| Diameters| |ounces. | in lines.| +----------+----------+ | 16 | 19½ | | 12 | 17 | | 8 | 15 | | 7 | 14¾ | | 6 | 14¼ | | 5 | 13 | | 4 | 12⅓ | | 3 | 11½ | | 2 | 9⅙ | | 1 | 6½ | +----------+----------+
Here, it is evident, that the mould of a rocket of twelve ounces in weight, ought to be seventeen lines (12 lines to the inch) in diameter; and one of five ounces, will require a mould of thirteen lines in diameter. Hence, we derive an easy method of finding the size, when the weights are given: and, if the diameter of the rocket be given, it will be equally easy to find the weight of the ball, corresponding to the weight of that caliber.
_TABLE_ II. _Size of the caliber of moulds, of from one to fifty pound ball._
------+---------+------+---------+------+---------+------+--------- Pounds| Caliber |Pounds| Caliber |Pounds| Caliber |Pounds| Caliber ------+---------+------+---------+------+---------+------+--------- 1 | 100 | 14 | 241 | 27 | 300 | 40 | 341 2 | 126 | 15 | 247 | 28 | 304 | 41 | 344 3 | 144 | 16 | 252 | 29 | 307 | 42 | 347 4 | 158 | 17 | 257 | 30 | 310 | 43 | 350 5 | 171 | 18 | 262 | 31 | 314 | 44 | 353 6 | 181 | 19 | 267 | 32 | 317 | 45 | 355 7 | 191 | 20 | 271 | 33 | 320 | 46 | 358 8 | 200 | 21 | 275 | 34 | 323 | 47 | 361 9 | 208 | 22 | 280 | 35 | 326 | 48 | 363 10 | 215 | 23 | 284 | 36 | 330 | 49 | 366 11 | 222 | 24 | 288 | 37 | 333 | 50 | 368 12 | 228 | 25 | 292 | 38 | 336 | | 13 | 235 | 26 | 296 | 39 | 339 | | ------+---------+------+---------+------+---------+------+---------
By this second table, if the weight of the ball be given, the size of the mould may be found: suppose it be eighteen pounds; opposite to it is the number 262. Then we say, by the rule of proportion, (as 19-1/2, see Table 1, is supposed to be divided into a hundred parts) 100 : 19-1/2 : : 262 to the fourth term sought, viz. 51.09; which gives for the required caliber 52 lines nearly, or four inches and four lines. But if the caliber be given in lines, the weight of the ball may be found: suppose the given caliber be 36 lines, then as 19-1/2 : 100 : : 36 : 184. The nearest number in the table to this is 181, which shows that the weight of the ball will be rather more than 6 lbs; or, in other words, that a rocket, the diameter or caliber of which is thirty-six lines, is a rocket of a 6 lb. ball. See _Congreve Rocket_.
As to moulds to prevent the rockets from splitting in the act of charging them, Morel observes, that he has never used them. He remarks, that a case which will not resist the force of the charge, cannot resist the violence of the fire.
On the subject of compositions, he observes, that he has only employed one formula, and, of course, but one standard proportion for all sized calibers; and is of opinion, that it is useless to employ an inferior composition, or one with which we are unacquainted, when we have a formula, on which we may rely. This opinion, however, does not agree with that of others.
Certain rockets, it is to be remarked, show tails of fire in their flight, and others again do not. This depends entirely upon the charcoal; for, if we use charcoal, made from tender and light wood, it burns rapidly, without producing a tail of fire; but if we use the charcoal of oak or of beech, or of other hard wood, the rocket will form a brilliant tail of fire, during the whole period of its ascension. It is said, however, that the charcoal of light wood, is lighter and more inflammable, and for that reason, better calculated for rockets; but, so far from producing the effect, we have mentioned, a quick combustion ensues, leaving no ignited coal to be acted upon by atmospheric air.
It is found by experiment, that even a little more or a little less powder, gives to or takes from, the composition its effective power; and, therefore, that the rockets, in their flight, ascend to a greater or less height.
Some writers have asserted, that powder ought not to enter into the composition of rockets; but in lieu thereof, only its component parts. Where, we may inquire, is the difference? The reason, however, assigned, is, that rockets made with gunpowder and the other substances, will not keep any time, owing to the powder becoming damp, and the composition spoiled. But rockets which have been made in France and carried to the East Indies, and brought back, were found, on trial, not to have lost any of their effect.
Different opinions have also been entertained, respecting the composition for the charging of rockets. Some, it appears, would employ a composition for each rocket, according to its caliber, pre-supposing, that the inflamed matter acquired force by the increase of its volume; without considering, that a large rocket has more weight than a small one, and requires more power to raise it. Experience has demonstrated, that a composition which will completely raise a rocket of three-quarters of an inch, will raise, under the same circumstances, a rocket of three inches; and, on the contrary, that the last will ascend more slowly, in consequence of having to encounter a greater resistance in the air, owing to its size.
_Sec. II. Of the Composition of Sky-rockets, and Observations on its Preparation, and on other Subjects respecting Rockets._
The formulæ we here give, which we notice separately from the others, are on the authority of Morel, who, by experience, has found them to excel all others. Nevertheless, we purpose to enumerate other formulæ for the information of the reader.
_Composition of Sky-Rockets, according to Morel._
_For Summer._ _Another._
1. Saltpetre, 17 oz. 2. Saltpetre, 16 oz. Sulphur, 3½ -- Sulphur, 4 -- Meal-powder, 1½ -- Charcoal, 7½ -- Charcoal of oak, 8 --
_For Winter._ _Another._
3. Saltpetre, 17 oz. 4. Saltpetre, 44 oz. Sulphur, 3 -- Sulphur, 4 -- Meal-powder, 4 -- Charcoal, 16 -- Charcoal of oak, 8 --
_Another._ _Another._
5. Saltpetre, 16 oz. 6. Sulphur, 3 oz. Sulphur, 2 oz. 3 drachms. Saltpetre, 20 -- Charcoal, 6 oz. Charcoal, 8½ --
_Chinese Composition for rockets of honour._
Saltpetre, 5 ounces. Sulphur, 1¼ ---- Charcoal, 2½ ---- Meal powder, 1 ---- Pulverized cast iron, 2½ ----
Two compositions for rockets of any caliber are given by Bigot; (p. 122); viz.
_Rockets of Honour._
Meal powder, 2 parts. Saltpetre, 10 ---- Sulphur, 2½ ---- Charcoal, 5 ---- Cast iron, pulverized, 5 ----
_Particular Composition._
Saltpetre, 16 parts. Sulphur, 4 ---- Charcoal, 9 ---- Antimony, 2 ----
In the old authors on fire-works, there are a variety of formulæ for sky-rockets, which will be found in the following table:
------------------+------+------+------+------+------+----------------- Kinds of Rockets.| Meal |Salt- |Char- |Steel |Sul- | REMARKS. |powder| petre| coal | | phur | ------------------+------+------+------+------+------+----------------- |lb.oz.|lb.oz.|lb.oz.|lb.oz.|lb.oz.| Rockets, 4 oz. | 1 4 | 0 4 | 0 2 | 0 0 | 0 0 | Do. 8 oz. | 1 0 | 0 4 | 0 1½| 0 0 | 0 3 | Do. do. | 1 8 | 0 0 | 0 4½| 0 0 | 0 0 | Do. 1 lb. | 2 0 | 0 8 | 0 2 | 0 1½| 0 4 | Do. in general, | 0 0 | 4 0 | 1 8 | 0 0 | 1 0 | Do. do. | 0 2 | 4 0 | 1 12 | 0 0 | 1 8 | Do. large fly, | 1 0 | 4 0 | 0 0 | 0 0 | 1 0 | Do. of a middling | 3 0 | 8 0 | 0 0 | 0 0 | 3 0 | size | | | | | | Do. do. | 1 0 | 3 0 | 1 0 | 0 0 | 2 0 | Do. water, | 6 0 | 4 0 | 5 0 | 0 0 | 3 0 | The proportion of | | | | | |charcoal is cer- | | | | | |tainly too great. Do. do. | 0 0 | 1 0 | 0 6 | 0 0 | 0 4½| Do. do. | 0 0 | 1 0 | 0 12 | 0 0 | 0 4 | Do. do. | 0 0 | 4 0 | 1 12 | 0 0 | 1 8 | Do. do. | 4 0 | 4 0 | 0 0 | 0 0 | 2 0 | Do. do. | 0 4 | 1 0 | 0 2 | 0 0 | 0 8½| Do. do. | 1 0 | 3 0 | 0 8½| 0 0½| 1 0 | Sea-coal, 1 oz. | | | | | |saw-dust, ¾ oz. | | | | | |coarse char. ¼ oz. Do. do. | 1 12 | 3 0 | 0 12 | 0 0 | 1 8 | Sawdust, 2 oz. Do. do. sinking}| 0 8 | 0 0 | 0 12 | 0 0 | 0 0 | charge, }| | | | | | ------------------+------+------+------+------+------+-----------------
The charcoal ought not to be pulverized very fine. It should be passed through a coarse wire sieve, and the impalpable powder then separated, by submitting the sifted charcoal to the same operation in a finer sieve. The fine charcoal may be used for small fire-works.
The instructions, heretofore given, for the mixture of compositions must be attended to; as, for instance, when we have weighed the powder, nitre, and sulphur, the whole are to be incorporated in a mortar, and then passed three times through a large sieve. Afterwards add the charcoal, which is mixed thoroughly with the hand. (See the _Mixture of Substances_, part second). With respect to the rammers, the mode of charging, &c. see section iii, of part second.
In charging cases of half an inch caliber, fifteen blows with the mallet must be given; for three-quarters of an inch, twenty blows; for one inch, twenty-five blows; for one and a quarter inches, thirty blows; one and a half inches, thirty-five blows; for two inches, forty blows; and for three inches, fifty blows;--that is to say, the number of blows must be given to each charge put in, which ought to occupy half the interior diameter of the case. The rammer must be frequently taken out, and struck, so as to disengage any of the composition, which may adhere to it. Respecting the accuracy of the charge, see _Table rocket_, in the chapter on _Table fire-works_.
The garnishing, or furniture, should not exceed, in any case, one-third the weight of the rocket. The head is made of pasteboard, first moistened, and then rolled round a conical former. It must enter the mould, and, when inserted, ought to be pasted round the juncture with paper. (See sec. iii, and iv.)
With respect to rocket sticks, as they are used for counter-weights, Morel remarks, that, for rockets up to an inch and a quarter, they may be formed of the branches of light wood, as hazle, elder, &c. and for rockets above that caliber, heavy wood, but perfectly straight and without knots, may be used. As a general rule, the sticks are made ten or twelve times the length of the rocket, and in thickness about one-third of the exterior diameter of the case. In the large end of the stick, there is a gutter or groove, formed to receive the rocket. When branches are used, they must also lie straight, and cut flat at the large end, about half their thickness, so that they may be joined to the rockets with a pack-thread, or fine iron wire. If the stick is too weighty, it may be shaved off the whole length. Rockets, we may remark, that are not well balanced by the stick, will not ascend regularly. If the stick be too light, they will rise in a zigzag direction; but, if too heavy, their accelerated force will be diminished, their motion slow, and, when they arrive at a certain height, they will fall in a semicircular position. (See section v, of this chapter, _on the Dimensions and Poise of rocket sticks_.)
We may further remark, that all rockets are formed and proportioned by the diameter of their orifice. When the height is six and two-thirds diameter, the foot should be one diameter and two-thirds. The choak of the mould, if used, is one diameter and one-third in height, which must be made out of the same piece as the foot, and fit tight in the mould. There must be an iron pin to keep the foot fast. The nipple is half a diameter high, and two-thirds thick, and made of the same metal as the piercer. The height of the piercer is three and a half diameters, and at the bottom one-third of a diameter thick, and from thence tapering to one-sixth of a diameter. The best mode of fixing the piercer in the cylinder, is to make that part below the nipple sufficiently long to go entirely through the foot, and rivet at the bottom. The former or roller, for the cases, is seven and a half diameters from the handle, and its diameter is two-thirds of the bore. The end of the former is one diameter and two-thirds long, and of the thickness given above. The small part, which fits in the hole in the end of the roller, when the case is pinched, is one-sixth and one-fourth of the diameter of the mould thick. The first drift, or rammer, must be six diameters from the handle; and this, as well as all other rammers, must be a little thinner than the former, to prevent the sacking of the paper, when the charge is driven. In the end of this rammer must be a hole to fit over the piercer. Several hollow rammers are used in completing the charge. (See our remarks in part second on _Charging of cases_.)
The diameter of the nipple should always be equal to that of the former. With regard to the thickness of moulds, it is immaterial, provided they are substantial and strong. Solid driving is more expeditious than charging over a piercer; but great labour and attention is required in boring them, an account of which, with the apparatus required, may be seen in _Part second_.
The following table of the dimensions of rocket-moulds, if the rockets are rammed solid, may be useful.
-----------+---------------+-----------------+-------------- |Length of their| | Weight of |moulds without |Internal diameter|Height of the rockets. |their feet. | of the moulds. | nipples. -----------+---------------+-----------------+-------------- lbs. oz. | Inches. | Inches. | Inches. -----------+---------------+-----------------+-------------- 6 0 | 34.7 | 3.5 | 1.5 4 0 | 38.6 | 2.9 | 1.4 2 0 | 13.35 | 2.1 | 1.0 1 0 | 12.25 | 1.7 | 0.85 0 8 | 10.125 | 1.333 &c. | 0.6 0 4 | 7.75 | 1.125 | 0.5 0 2 | 6.2 | 0.9 | 0.45 0 1 | 4.9 | 0.7 | 0.35 0 0½ | 3.9 | 0.55 | 0.25 6 drachms.| 3.5 | 0.5 | 0.225 4 drachms.| 2.1 | 0.3 | 0.2 -----------+---------------+-----------------+--------------
_Sec. III. Of the Heading of Rockets._
The heads for sky-rockets must always bear a given proportion to the rockets.
A pointed cap, adapted to the summit, will make a rocket ascend to a greater height, as it serves to facilitate its passage through the air. To these rockets may be added several other things; as a petard, which is a box of tin plate, filled with fine gunpowder, placed on the summit. The petard is put on the composition, at the end, when it has been filled, and the remaining paper of the cartridge is folded down over it, to keep it firm. The petard produces its effect, when the rocket is in the air, and the composition is consumed. We have already remarked, that the upper parts of rockets, that is to say, their _heads_, are generally furnished with some composition, which takes fire, when it has reached its greatest height, emits a considerable blaze, or produces a loud report and whizzing noise. Of this kind are saucissons, marrons, stars, showers of fire, &c. The heads of sky-rockets, are, therefore, furnished with a variety of compositions.
When a rocket is five diameters, and one-sixth in length, the case being cut to this length, after it is filled, the head should be two diameters high, and one diameter 1/6th, and 1/2 in breadth. The perpendicular height of the cone, or cap of the head, must be in diameter, one, and one-third. There is a circular collar, to which the head is fixed, turned out of any light wood; its exterior diameter must be equal to the interior diameter of the head. One-sixth is sufficient for its thickness, and round the outside must be a groove. The interior diameter of the collar should not be quite so wide as the exterior diameter of the rocket. When it is to be glued on the rocket, two or three rounds of paper are to be cut off, which will make a shoulder for it to rest upon. Two or three rounds of paper well pasted, will be sufficient for the head. Put the collar on the mandril, or former, which must fit the inside of the cone when formed; then, with a pinching cord, pinch the bottom of the head into the groove, and tie it with small twine. To make the caps, cut the paper in round pieces, equal in diameter to twice the length of the cone, which is to be made. These pieces, being cut into halves, will make two caps each. Paste over the caps a thin white paper, which must be a little longer than the cone, so as to project about half an inch below the bottom: this projection of paper being matched and pasted, serves to fasten the cap to the head, A conical former is used to shape the head.
_Sec. IV. Of the Decorations for Rockets, and the Manner of filling their Heads._
Having, in the preceding section, shown the mode of forming heads, or conical caps, for rockets, we may now remark, that the furniture or decorations for rockets consist of stars of different kinds, such as tailed, brilliant, white, blue, yellow, &c. or gold and silver rain; or serpents, crackers, fire-scrolls, or shining marrons, or small rockets; the kind of the decoration depending entirely upon taste and fancy.
In loading the heads of rockets, a ladleful of powder must be put into each head, along with the decorations. This is absolutely necessary in order to burst the head and disperse the stars, &c.
Various experiments have been instituted, to make rockets, by employing sundry compositions for charging the cases, along with the rocket composition, to produce, like the heads of rockets, when they burst, different appearances. M. Morel informs us, that he made several experiments with that view, but did not succeed. He ascribes the failure to several causes; and, in substance, concludes, that such figures have a greater weight than rockets are able to carry; that their irregular forms and movements produce, in the ascension, a contrariety of effects, which impedes their flight; and that, if they were to succeed, the rapidity, with which the fuse passes through the air, would prevent any thing being distinguished. As such exhibitions are shown with effect, by the bursting of the head of the rocket, after it has ceased to burn; we are of opinion, that the only mode, which can be adopted, with success, is the one already described. For after the rocket has ceased, or finished, the last portion of fire is communicated to the head, containing the decorations, which is blown off, and its contents are inflamed and dispersed. It is true, however, that, in some compositions, stars, previously made, and therefore not mixed with the composition, are put in the cases along with the charge: We have an instance of this in the fire-pump, Roman candle, &c. The cases for these are filled in the following order: first with gunpowder to a certain extent, then a star, then composition; then powder again, then another star, and so on alternately, until the charge is completed; but, in this instance, the star, as well as the gunpowder, is distinct from the composition, which forms the fire-pump. For, while the composition performs one part, the gunpowder acts another, by throwing the stars out, which, by their combustion, give the appearance they are intended to produce. Stars may be formed, or rather exhibited, in this way, which, in fact is much after the manner, in which they are used for the heads of rockets. But the experiments of Morel appear to have been made, with a view to produce that effect from the rocket itself, and altogether by the composition, by varying or otherwise modifying it. Star-composition, it must be observed, is of a greater specific gravity than any ordinary composition, in consequence of the weight, and quantity of metallic and other substances, which enter into it. By arranging stars in cases, in the mode described for the fire-pump, the effect, we have spoken of, always takes place. In rockets, however, which require to be driven with considerable force, and over a piercer, they could not be used.
_Sec. V. Of the Dimensions and Poise of Rocket-sticks._
Although we have made some observations on the size, as well as the use of rocket-sticks, in a general way; yet the subject being very important, as rockets, however well made, cannot take a vertical direction without them, we subjoin the following table, which exhibits, at one view, the length, &c. of the stick, compared with the weight of the rocket, and the poise it must necessarily have from the point of the cone. The _centre_ of gravity is a necessary consideration.
---------+------------+-----------+---------+-----------+------------- Weight | | | | | Poise from of the | Length of | Thickness | Breadth | Square at | the point of rocket. | the stick. | at top. | at top. | bottom. | the cone. ---------+------------+-----------+---------+-----------+------------- lbs. oz. | Ft. In. | Inches. | Inches. | Inches. | Ft. In. ---------+------------+-----------+---------+-----------+------------- 6 0 | 14 0 | 1.5 | 1.85 | 0.75 | 4 1.5 4 0 | 12 10 | 1.25 | 1.40 | 0.625 | 3 9. 2 0 | 9 4 | 1.125 | 1. | 0.525 | 2 9. 1 0 | 8 2 | 0.725 | 0.80 | 0.375 | 2 1. 0 8 | 6 6 | 0.5 | 0.70 | 0.25 | 1 10.5 0 4 | 5 3 | 0.3750 | 0.55 | 0.35 | 1 8.5 0 2 | 4 1 | 0.3 | 0.45 | 0.15 | 1 3. 3 1 | 2 6 | 0.25 | 0.35 | 0.10 | 11 0. 0 0½ | 2 4 | 0.125 | 0.20 | 0.16 | 8 0. 0 0¼ | 1 10½ | 0.1 | 0.15 | 0.5 | 5 0.5 ---------+------------+-----------+---------+-----------+-------------
** Transcriber Note: the last three rows of this table have many typos. The rows were probably intended to be as follows:
0 1 | 2 6 | 0.25 | 0.35 | 0.10 | 1 1. 0 0½ | 2 4 | 0.125 | 0.20 | 0.16 | 0 8. 0 0¼ | 1 10½ | 0.1 | 0.15 | 0.5 | 0 5.5 ---------+------------+-----------+---------+-----------+------------- ** end of Transcribers Note **
The last column expresses the distance from the top of the cone, where the stick, when tied on, should balance the rocket, so as to stand in equilibrium on the edge of a knife.
Having given the method of preparing sticks, nothing more is necessary on that head, except that they should be cut and planed according to the dimensions in the table. A groove must be made the length of the rocket, and as broad as the stick will allow. Two notches may be cut on the opposite flat side, for the cord which ties on the rocket. The top of the stick should always touch the head. In fixing on the stick, care must be taken to secure it well.
It is the stick which gives a proper counterpoise, without which the rockets would not ascend; and, unless they were of a proper length and weight, instead of taking a vertical or perpendicular direction, they would describe a parabola, or take an oblique course, and fall to the ground.
A rocket stick may be made for any sized rocket, although not expressed in the table, by assuming the data there given, taking care to find the centre of gravity. For the sticks for war-rockets, see _Congreve Rocket_.
_Sec. VI. Of the Mode of Discharging Rockets._
Having completely prepared the rockets with all their appendages, we consider in the next place the manner of discharging them; in performing which some care is to be observed. The old and heretofore common manner, of setting them off by hanging them on nails and hooks, has many objections. The best mode is to have a ring made of strong iron wire, large enough for the stick to go in, as far as the mouth of the rockets. Then let this ring be supported by a small iron, at some distance from the post or stand, to which it is fixed; and have another ring fixed in the same manner, to receive and guide the small end of the stick. Rockets, thus suspended, will have nothing to obstruct their flight. The upright, to which the rings are fixed by the small iron, must be exactly vertical.
Two, three, or more sky-rockets may be fixed on one stick, and fired together. Their appearance, in this case, is very striking. Their tails will seem but as one of immense size, and the discharge from so many heads, at the same time, will resemble more the effect of an air balloon. Rockets, for this purpose, must be made alike in every particular. If the rockets are half-pounders, whose sticks are six and a half feet long, then two, or three, or six of these are to be fixed to one stick, the length of which must be nine feet and three-quarters. 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 of these sides, let a groove be made. From this groove, plane it round, down to the end. The rule is, that the stick at top must be sufficiently thick, when the grooves are cut, for all the rockets to lie as near as possible, without pressing each other. When only two rockets are to be fixed on one stick, let the length of the stick be the last given proportion, but shaped after the common method, and the breadth and thickness, double the usual dimensions.
When several rockets are placed upon one stick, there will be some danger of their flying up without the stick. Cases, when tied on all sides of the stick, cannot be secured to it by rope passing over notches as before mentioned. Instead of which, drive a small nail in each side of the stick, between the necks of the cases; and let the cord, which goes round their necks, be brought close under the nails. A quick match, without a pipe, is to be fixed to the mouth of one rocket, and carried to another. This match will communicate fire at one and the same time.
There is a mode of discharging sky-rockets without sticks, which consists in using balls of lead tied to a wire two or three feet long, and fixing the other end of the wire to the neck of the rocket. These balls answer the purpose of sticks, when made of a proper weight, which is about 2/3ds the weight of the rocket. They will balance the rocket at the usual point. To fire rockets, thus equipped, a different mode must be adopted. They are hung, one at a time, between the tops of wires placed for that purpose, letting their heads rest on the wire, and the balls hang down between them. The wires are about three feet long, and inserted in a circle, in a block of wood, which must lie level, and the wires perfectly vertical. The diameter of the circle is two and a half inches; it is divided into three equal parts, and at each one is a rod or wire.
We may introduce here a description of the _stands for sky-rockets_, and the _girandole chests for the flights of rockets_. The first is formed of two rails of wood, of any length, supported at each end by a perpendicular leg, so that the rails lie horizontal; and let the distance from one to the other be almost equal to the length of the sticks of the rockets, intended to be fired. Then in the front of the top rail, drive square hooks at eight inches distance, with their points turning sidewise; so that, when the rockets are hung on them, the points will be below the sticks, and keep them from falling or being blown off by the wind. At the front of the rail at the bottom must be staples, driven perpendicularly under the hooks at top. Through these staples put the small ends of the rocket-sticks. They are fired by applying a lighted port-fire to their mouths. Two or three seconds will expire before they ascend.
_The girandole chest_ is composed of four sides of equal dimensions; but may be made of any size, according to the number of rockets to be fired. Its height must be in proportion to the rockets, and higher than the rockets with their sticks. When the sides are joined, fix in the top, as far down the chest as the length of one of the rockets with its cap on. On this top, make as many square or round holes, to receive the rocket-sticks, as the number of rockets to be fired; but let the distance between them be sufficient to prevent their touching each other. From one hole to another cut a groove of a sufficient size for a quick match to lie in. The top being thus fixed, put in the bottom, at about 1-1/2 feet distance from the feet of the chest. In this bottom, make as many holes as at the top, and all to correspond, but not so large as those in the top.
To prepare the chest, a quick match is laid in all the grooves, from hole to hole. Then take the sky-rockets, and prime them with meal-powder, or priming paste, as before-mentioned, and put a bit of match up the cavity of each, which should project out. Put the sticks of the rockets through the holes in the top and bottom of the chest, so that their mouths may rest on the quick match in the grooves. The rockets will then be fired at once. There should be a door in the side of the chest, and also a cover, to secure the rockets until they are required.
The _fountain of rockets_, an exhibition which frequently accompanies a display of works, is nothing more than a number of rockets discharged at the same time.
There are some improvements on the girandole chest, and on the different modes of discharging a series of rockets.
We may mention one contrivance for this purpose, as described by Morel. It is an oblong box furnished with a double lid, which, when shut, resembles the roof of a house. This box is sixty inches in length, ten inches in breadth, and nine inches in height. It rests upon a frame, and has a bottom in which are one-hundred holes, to receive the same number of rocket-sticks, the rockets resting on the bottom of the box. The lid serves to prevent the access of moisture, and to secure the rockets. No part of the rocket is seen in the box. They are set off by first strewing meal-powder on the bottom, which is then in contact with their mouths, and applying a lighted port-fire. They rise out of the box all together, and at the same time. When fired together, so as to form a _flight_ of rockets, the French use them of three-quarters of an inch caliber.
The _girandole_ may be considered an assemblage of a large number of rockets of various calibers, arranged in gradation; the largest, occupying the first range, &c. The girandole constitutes, as a fire-work, in the language of Morel, the _feux de gouvernement_.
Similar to this is a contrivance for the same purpose, but not so extensive, and rather differently formed. It consists of a case, in which there are holes to receive the sticks and support the rockets. The case is supported by legs; two of which, working upon a joint, may be extended, and thus the rockets be made to move in any angular direction. The inclination given is hardly ever more than 55 degrees. The legs are pointed, so as to retain their position. If the rockets are to ascend vertically, the two legs, which move in a joint, are closed. They are stuck in the ground at the same place.
For the mode of discharging the _Congreve Rocket_, see the article on _Congreve Rockets_.
_Sec. VII. Of the Appendages, and Combinations of Rockets._
We purpose to notice, in this section, some of the modes of arranging, combining, and also of varying the effects of rockets.
When a sky-rocket is fixed with its stick on the top of another, a fresh tail of fire will be observable, when the second rocket takes fire, which will mount to a great height. The preparation of these rockets consists in filling a two pounder only half a diameter above the piercer, (which must be observed in this instance,) and its head with not more than ten or twelve stars; adapting a stick as usual, which must be made a little thicker than customary. This stick must be cut in half the way flat, and in each half a groove, so that, when joined together, they will receive, and be large enough to hold the stick of a half pound rocket. The heading is then performed as before described. The stick of this small rocket is to be fixed in the hollow of the large one, so far that the mouth of the rocket may rest on the head of the two pounder; and, from the head of the two pounder, a leader is to be carried into the mouth of the small rocket.
When sky-rockets are fixed one on the top of another, they are called _towering rockets_, on account of the great height to which they ascend. They are made in the following manner: Fix on a pound rocket, a head without a collar; then take a four-ounce rocket, which may be headed or bounced, and rub the mouth of it with priming paste, or meal-powder and spirits of wine. Put it into the head of a large rocket with its mouth downwards, previously, however, inserting a bit of quick match in the hole made through the clay of the pound-rocket, which match should be of a sufficient length to go a small distance up the bore of the small rocket, to fire it when the large one is burnt out. The four-ounce rocket being too small to fill the head of the other, roll round it as much tow as will make it stand upright in the centre of the head. Then paste a single paper round the opening of the top of the head of the large rocket. The large rocket must have only half a diameter of charge rammed above the piercer; for, if filled to the usual height, it would turn before the small one takes fire, and entirely destroy the intended effect. When one rocket is headed with another, there will be no occasion for any _blowing powder_; for the force with which it flies off will be sufficient to disengage it from the head of the first fired rocket. The sticks for these rockets must be a little longer than for those headed with stars, rain, &c.
The _caduceus rockets_ are formed of two rockets. When attached, one on each side at the top of the stick, they form a right angle, their mouths being equidistant from the stick. The sticks, for this purpose, must have all their sides alike, which should be equal to the breadth of a stick, proper for a sky-rocket of the same weight as those intended to be used, and to taper downwards as usual. They must be long enough to balance them, and one length of a rocket from the cross-stick. The cross-stick is that to which the cases are tied, and serves to preserve them steady in that position. Each rocket, when tied on, should form either an angle of 45, or 60 degrees with the large stick, or both together an angle of 90 or 120 degrees. The last, however, is considered a preferable angle. When tying on the rockets, attention ought to be paid to place their heads on the opposite sides of the cross-stick, and their ends on the opposite sides of the long stick. Quick-match is then to be carried from the mouth of one into that of the other. When these rockets are to be fired, suspend them between two hooks or nails, and apply fire to the leader in the middle, and both will take fire at the same time.
The particular effect of this rocket is, that, in rising, it forms two spiral lines, or double worms, in consequence of their oblique position; and the counterpoise in the middle (the stick) causes them to ascend vertically. Rockets, for this purpose, must have their ends choaked close, without either head or bounce; for a weight at top would be an obstruction to their mounting. They do not rise so high as single rockets, because of their serpentine motion, and the resistance they meet with in passing through the air. This resistance is greater than two rockets of the same size fired singly.
_Honorary rockets_ are nothing more than sky-rockets, except that they carry neither head nor report. They are closed at top, to which is attached a cone. On the case, close to the top of the stick, a two-ounce case is tied. This last is filled with a strong charge, and is usually about five or six inches in length, and pinched close at both ends. At the opposite sides, at each end, a hole must be bored, in the same manner as in tourbillons; and from each hole, a leader must be carried into the top of the rocket. When the rocket is fired, and has arrived at its proper height, it will communicate fire to the case at the top, which will cause the rocket and stick to descend very fast to the ground, and, in its descent, will represent a worm of fire.
There are several modes of placing the small case, so as to produce the best effect. One is by letting the stick rise a little above the top of the rocket, and tying the case to it, so as to rest on the rocket. These rockets are not furnished with cones. Another method is also recommended; namely, in the top of the rocket, fix a piece of wood, in which drive a small iron spindle; then make a hole in the middle of the small case, through which put the spindle, and fix, on the top of it, a nut, to keep the case from falling off. The case, by this means, will turn very fast, without the rocket. This method, however, is not preferred.
One-pound rockets are considered the best size for this purpose.
_Chained rockets_, as they are sometimes called, are another modification of the manner of fixing rockets; for the intention is to make several sky-rockets rise in the same direction, and equally distant from each other. This effect is produced in the following manner: Take six, or any number of sky-rockets, of any size; 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 way;--after tying one end of the 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 outside, will be fastened to two pieces of pack thread. The length of thread, from one rocket to the other, is indeterminate. They must all be of a size, and their heads filled with the same weight of stars, or other decorations.
In the mouth of each rocket, a leader is to be fixed of the same length, and when fixed, they may be hung almost close. Tie the ends of the leaders together, and prime them: When this is fixed, all the rockets will mount at the same time, and separate as far as the strings will admit. They will preserve the same order and distance, if they are rammed alike, and equally well made.
The manner of dividing the tail of a sky-rocket, so as to form an arch when ascending, is thus performed. Having some rockets made, and headed according to fancy, and tied on their sticks, get some sheet tin, and cut it into round pieces of about three or four inches in diameter. Then, on the stick of each rocket, under the mouth of the case, fix one of these pieces of tin, sixteen inches from the head of the rocket, and support it by a wooden bracket as strong as possible. The use of this is, that, when the rocket is ascending, the fire will play with great force on the tin, which will divide the tail in such a manner, as to form an arch. If there is a short piece of port-fire, of a strong charge, tied to the end of the stick, it will add greatly to the appearance; but this must be lighted before fire is put to the rocket.
_Sec. VIII. Of Swarmers, or Small Rockets._
Although swarmers are nothing more than rockets of a smaller size, as from two ounces downwards, and are charged with the usual rocket composition, which we have described; yet it may be necessary to make some remarks respecting them.
Swarmers are sometimes fired in flights, or in a volley, and in large aquatic fire-works. They are bored in the same manner as large rockets, or pierced in the act of charging them. This is the case with those of one and two ounces. All rockets, however, under one ounce, are not bored, but must be filled to the usual height with composition. The number of strokes for ramming these small swarmers is not material, provided they are rammed true and moderately hard. The necks of unbored rockets must be in the same proportion as in common cases. The composition, with which small swarmers are charged, generally consists of
Meal-powder, 4 oz. Charcoal, or steel-dust, ¼ oz.
As to the swarmers which are pierced, or bored, _viz._ those of one and two ounces; they are made, we observed, in the same manner as large rockets, with the exception, that, when headed, their heads must be put on without a collar. The number of strokes for driving one-ounce cases must be eight, and for two-ounce, twelve.
_Sec. IX. Of Scrolls for Sky-Rockets, and of Strung, Tailed, Drove, and Rolling Stars._
We have given, in a preceding chapter, the composition of various stars, which are used for the decoration of sky-rockets, and other species of fire-works. We shall, therefore, confine ourselves to their application, and the different modes of preparing them for this purpose.
_Scrolls_ are used as furniture, or decorations for sky-rockets, and are so named from the spiral form they assume, when fired very quick in the air. We may put into the head of a rocket, as many of the cases as it will contain. Cases for scrolls should be four or five inches in length, and their interior diameter, three-eighths of an inch. One end of these cases must be pinched quite close before it is filled; and, when filled, the other end must also be closed. Then, in the opposite sides, make a small hole at each end, in the same manner as in tourbillons, and prime them with priming paste, or meal-powder and brandy.
_Strung Stars_, so named from having a cotton quick match run through them, are formed by taking some thin paper, and cutting it into pieces of about one and a half inches square, and laying on each piece, as much dry star composition as the paper, when folded, will easily contain. The paper, with its contents, is then twisted up as hard as possible. When done, rub some paste between the hands, and roll the stars between them, and afterwards dry them. They are then covered with tow, and primed with a paste composed of meal powder, and brandy, in which they may be rolled in the same manner as described when treating of stars. They are then dried and strung on cotton quickmatch, by piercing a hole through them, taking care to put but ten or twelve on each match, and placing them at the distance of three or four inches apart.
_Tailed stars_ are those which produce a great many sparks, representing a tail like that of a comet. Of these, there are two kinds, the rolled and the drove. The operation for the rolling of stars, we have sufficiently explained; it consists in mixing the composition with brandy, or, if it can be had, with spirit of wine, and either weak gum water, or isinglass size, sufficient to make a thick paste; and then rolling it.
When tailed stars are to be driven, the composition must be moistened with spirit of wine, or if it cannot be had, with fourth proof brandy, without the gum, or gelatin, and not made so wet as for rolling. One or two-ounce cases, rolled dry, are best for this purpose; and when they are filled, unroll the cases within three or four rounds of the charge, and all that is unrolled must be cut off. Then paste down the loose edge; and in two or three days afterwards, cut them in pieces of five or six-eighths of an inch in length; then melt some wax, and dip one end of each piece into it, so as to cover the composition. The other end must be covered with priming paste.
_Drove stars_ are so designated, because the composition is always drove, and used in cases. They are seldom put in rockets, but are chiefly used for air-balloons. They are put in cases, to prevent the composition from being broken, by the force of the blowing powder in the shell. See _Air-Balloons_.
With respect to _rolling stars_, we gave, in our chapter on star compositions, not only the proportion of their constituent parts, but ample instructions for preparing them for use. They are usually about the size of a musket ball; but sometimes they are made an inch in diameter. When very small, they are called _sparks_. See _Stars_.
_Sec. X. Of Line-Rockets and their Decorations._
Line-rockets are the same as the _courantines_ of the French, or rockets that fly along a rope. If a rocket be attached to an empty case, and a rope passed through the latter, and stretched horizontally; and if the rocket be then set on fire, it will run along the rope, without stopping till the matter it contains is exhausted.
Line-rockets do not differ materially from sky-rockets, as they are made and driven like them; but they are without heads, and the cases are cut close to the clay. They are sometimes made with six or seven changes. Four or five, however, are the most common. We must first have a piece of light wood, turned round, about two and a half inches in diameter, with a hole through the middle, lengthwise, and sufficiently large for a wire to go easily through. If four changes are required, four grooves must be cut in the swivel, one opposite the other, to lay the rockets in.
Having rubbed the mouths of the rockets with wet meal powder, lay them in the grooves, head to tail, and tie them fast. From the tail of the first rocket, carry a leader to the mouth of the second, and from the second to the third, and so on to as many as there are on the swivel, making every leader very secure; but in fixing these pipes, care must be taken, that the quick match does not enter the calibers of the rockets. The rockets being fixed on the swivel and ready to be fired, have a line, 100 yards long, stretched, and fixed up tight, at any height from the ground, but placed perfectly horizontal. This length of line will answer for half-pound rockets, but, if larger, the line must be longer. One end of the line, before it is put up, is to be put through the swivel; and when the line-rocket is fired, let the mouth of that rocket, which is set off first, face that end of the line where the operator stands, and the effect will follow in succession, _viz_: the first rocket will carry the rest to the other end of the line, the second will bring them back, and they will continue running out and in, according to the number of rockets. At each end of the line, there must be a piece of wood for the rocket to strike against, to prevent injury to the line. Let the line be well soaped, and the hole in the swivel very smooth.
In order to vary the appearance, different decorations may be used with the line-rockets; of these, _flying dragons_, _Mercuries_, &c. are the most conspicuous. Another motion may be given to them, that of revolving, in the following manner: Have a flat swivel, made very exact, and tie on it two rockets obliquely, one on each side; which will make it turn the whole length of the line, and form a circle of fire. The charge for these rockets, should be a little weaker than that usually employed.
It is apparent, that a variety of figures may be put in motion, and consequently new appearances formed, by different contrivances. To represent, for instance, two _fighting dragons_, we must have two swivels, made square; and on each swivel, tie three rockets together, on the under side. Then having two flying dragons, made of tin, fix one of them on the top of each swivel, so as to stand upright, and in the mouth of each dragon, put a case of common fire; and another at the end of the tail. Two or three port-fires may also be put on the sides of their bodies to illuminate them Put them on the line, one at each end; but let there be a swivel in the middle of the line, to keep the figures from striking together. Before the rockets are fired, light the cases on the dragons, and, if care be taken in firing both at the same time, they will meet in the middle of the line. They will then turn, and run back with great violence. The line for these rockets, must be very long.
_Sec. XI. Of Signal Sky-Rockets._
Signal rockets seldom exceed a pound in weight. Those which are employed in the land and sea service, are sometimes capped, or headed, and contain stars, serpents, &c. Two sorts of signals are used when artificial works are to be exhibited; namely, one with serpents, and the other without. 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, a small quantity of clay is put in. Then bounce and pinch them in the usual manner, and fix on each a cap. Signal sky-rockets, without bouncers, are only sky-rockets closed and capped. These are very light, and, therefore, do not require such heavy sticks as those with loaded heads. Signal rockets, with reports, are fired in small flights; and are often, as well as those without reports, used for signals of the commencement of an exhibition of fire-works.
Signal rockets may be seen at a great distance, and observed instantly, when neither flags nor telegraphs could be observed without glasses; and may be so formed, as even to communicate particular orders or intelligence, by varying their decorations, their mode of ascension, as in the caduceus rocket, and by several other means.