Part 4

9. You will next require a turned wooden former on which you can make paper cones of such a size at their base that they can be neatly pasted on to the top of your pots—that is, the base of these cones should have the same diameter as the pots. Although such conical caps are by no means necessary, yet they are a very great assistance to the rocket in its ascent, enabling it to rise with much less resistance through the air. The cone-former is represented in the annexed woodcut (fig. 20). To make these cones upon it, cut out as many circular pieces of brown paper as you require, the semi-diameter of which must be slightly greater than the height of the cones that you have to make. Then cut or tear these circles into halves and paste them on one side. Now place the first half-circle upon the former, pasted side outwards, taking care that the apex of the cone beat the point marked A in fig. 21. Then fold the brown paper neatly round the cone-former, and when you have made it to sit as closely to it as possible, proceed in the same manner with the other half-circle, putting it upon the first, pasted side inwards. The paper cones thus made must next be covered with one thickness of thin paper cut large enough to extend ½ an inch or rather more beyond the open end of the cone, and this projecting part, when notched all round with your scissors, can be pasted down round the top of the rocket pot. When this is done the pot will present the appearance of annexed illustration (fig. 22).

[Illustration:

Fig. 22.—Pot, with Conical Cap. ]

ROCKET STARS.

10. When all the pasting that has been necessary in making the pots is thoroughly dry, the filling them with stars is all that remains to be done for the completion of the rocket. You will find that the ¼lb. rocket will carry an ounce of stars well. After weighing out your stars, then, into parcels of this weight, empty one of these parcels into each pot. You will next require some sort of powder to strew among the stars which shall have the effect of igniting them and at the same time of bursting the pot. I have always found meal-powder by itself to be too rapid in its explosion to convey the fire to all the stars; many of them are blown out of the pot, never taking fire at all. The mixture which I should recommend you to use is the following:—

Meal-powder 6 parts. Fine charcoal 1 part.

Charcoal added to the meal-powder in the above proportion will render its combustion slow enough to light all the stars, without being too slow to burst the pot. Of this mixture take a ladleful (I mean the ladle which you use in filling your cases), and put it with the stars into the pot, which must now be securely glued over the clay end of the rocket-case.

ROCKET-STICK.

11. Lastly the rocket-_stick_ remains to be considered. This appendage is used for the purpose of keeping the mouth of the rocket _downwards_, so that if it move at all its motion must be an upward one. The rule for telling whether the stick be of the proper weight or not is the following:—After having tied it on to the rocket in the manner indicated in the page of illustrations, ascertain whether it will balance if laid across the finger about 2 inches from the mouth of the rocket. If the stick forms an exact counterpoise to the rocket at this point, it will answer your purpose very well. The length of the stick which I use for ¼lb. rockets is 4 feet, and its size about ⅜ × ½ inch. The best wood for these sticks is American pine. It is very light, and should be free from knots. You will be able to procure them much cheaper of Mr. Darby, and much more uniform in their make, than of any carpenter. In some old treatises upon pyrotechny you will find recommended a tapering rocket-stick, to the _large_ end of which the rocket is tied. I have never found any advantage which these sticks possess over those that are of one size throughout; and I think I may say that no professional pyrotechnist uses tapering rocket-sticks. On the annexed page of woodcuts (figs. 23 to 26) I have given you a sketch of the rings which I use, through which the rocket-stick must be passed, and from which the rocket is to be fired. These rings should be screwed into an upright post (fig. 27) standing 5 feet out of the ground; the upper ring near the top of the post, the lower about 3 feet from the ground. There is also a sketch (fig. 28) to show you how the rocket is to be suspended on this post.

I have stated above that there are _two_ ways of priming rockets; the one used for exhibition purposes I have already described. Rockets thus primed are fired by applying a lighted portfire to their mouth. The other method I have found very convenient when making trials either of rockets or of stars, for it enables you to get some distance from the rocket-post before the rocket rises, and consequently to gain a much better view of the object of your experiment. It is done in the following manner:—Paste or tie a piece of touch-paper round the mouth of the rocket which shall project an inch or rather more beyond the mouth. Then take a piece of uncased quick-match about 2½ inches long, and put it into the soul of the rocket, leaving so much of it outside the choke as can be twisted into the projecting part of the touch-paper. If this is done so as to leave a short twist of touch-paper beyond that part which contains the quick-match, you will gain a short interval of time between the moment of lighting the rocket and that of its ascent.

You can procure of Mr. Darby the cases _ready made_, and, in fact, anything employed in firework manufacture; but I strongly recommend you to learn to make the cases yourself, as you will then be not only much more independent, but also much more economical in your work.

Let me recapitulate a little, and add a few hints to remind you of certain points important in rocket manufacture.

Do not hurry over any part of the work, either the making the cases or the composition, or the ramming of the rockets.

In moistening your composition with spirits of wine or gin, be careful to add very little of the liquid, and to stir the composition about _very thoroughly_ until all the moisture that is present is very equally diffused.

Remember that the addition of nitre or meal-powder to your composition will render it more rapid in combustion; the addition of sulphur or charcoal more slow. By this means you can vary the strength of your rocket composition to any degree which proves successful or satisfactory in your hands.

By no means forget to bore a hole through the clay at the end of your rocket, and thus to form the communication with your stars.

Never allow your steel spindle to become rusty. Every coat of rust that you have to scour off from it diminishes the size of the spindle.

Remember that the work that is done neatest is always done best.

ROCKET STARS (How to Make).

12. By following a few simple directions for the manufacturing of these, you will be able to vary almost to any extent the heads of your rockets, and to produce combinations according to your taste and fancy.

The stars that are used as decorations to the different species of fireworks are of various kinds, sizes and shapes, according to the purpose for which they are intended.

1st. The ordinary rocket stars, which are called “brilliant” or “bright,” are made in small cubes. Their composition is moistened with gum-water, and while moist flattened to the thickness required. It is then scored or cut across with a knife, and allowed to dry. When dry it can be easily broken up into cubes at the places where it was divided by the knife. _Tailed_ stars are also made in the same way and of the same size.

2nd. Roman candle stars are small cylinders of composition made of a size proportioned to that of the case out of which they are to be thrown.

3rd. _Coloured_ rocket stars are made by driving the coloured composition, slightly moistened, into small cases, which go under the name of _pill-box cases_. If the star is to consist of one colour only, these pill-boxes are open at both ends, and a piece of quick-match is placed between the composition and the inside of the pill-box, and allowed to project about half-an-inch beyond each end of it. When fired, these stars burn at both ends at the same time, and so produce a great amount of fire in proportion to their size.

If it is required to make stars consisting of more than one colour (in which case they are called “changeable stars”), the pill-boxes are left open at one end only. The composition is thereby prevented from burning at more than one of its surfaces at a time. These stars generally contain _two_ colours; the pill-boxes are half-filled with one coloured composition and the remaining space filled with another. These changeable stars burn much longer than the others, and therefore produce a more beautiful effect; but being larger they require to be used in larger rockets, the _half-pound_ size being the smallest that is adapted for this purpose.

GOLDEN RAIN.

13. There is another and exceedingly beautiful decoration for rocket heads which is called golden rain. This is by no means a difficult thing to make. Some small paper cases are made, about 2 inches long and of the size of goosequills; these are filled with a sparkling composition and primed with wetted gunpowder. They are placed, mouth downwards, in the head of the rocket, and arranged in such a manner that they may _all_ be ignited. At the bursting of the rocket, they will describe a series of beautiful ringlets of sparkling fire.

I have now enumerated as many different kinds of stars, &c., as will provide you with the means of producing any amount of variety. I now come to the details of the manufacture of these decorations. We will begin with the ordinary

BRILLIANT STARS.

14. First, let me impress upon you the necessity of seeing that _all ingredients used in star compositions are in as fine a powder as possible_. You cannot have them too fine or too well incorporated and mixed. The following is the formula which I employ for the

COMMON BRILLIANT STARS. Nitre 16 parts Sulphur 8 „ Sulphuret of antimony 4 „ Meal-powder 3 „

Let all these ingredients be in fine powder, and, having carefully weighed out the quantities, mix them thoroughly. Next, take some gum-water of the strength previously mentioned—viz., two ounces of gum-arabic dissolved in a pint of warm water. Spread your star composition upon a piece of zinc plate or slate, and add to it a little of the gum-water at a time, taking care to stir the composition about _well_ till all the moisture is equally diffused through the whole. It is not necessary that this composition should be made _wet_, but only something like brown sugar in moistness, so that it will _bind well_ when pressed together. When you think this is sufficiently done, roll or press the composition into a flat shape like a thick pancake, and make it as square, or, at all events, as rectangular, as possible. Its thickness should be about _a quarter of an inch_. You will find a large spatula a very convenient tool in this operation, both for flattening the cake of composition and for getting it into a convenient shape. Now take your spatula, and with it score the composition across both ways, so that you have it divided into a number of little cubes, fig. 30.

It may then be set aside to dry in a warm place; it will be forty-eight hours before it is fit for use in summer, and about a week in winter. When dry you will have no trouble in separating the cubes at the marks left by the spatula.

[Illustration:

Fig. 30. ]

I may as well, however, introduce you to a simple piece of apparatus which will enable you to perform this operation much more comfortably and cleanly. I have a small wooden tray made of mahogany, six inches square, and three-quarters of an inch deep, _inside measurements_. Into this I place a flat piece of wood, which fits very easily into the tray, and is half-an-inch thick. This acts as a _movable false bottom_. It will be readily seen that when this false bottom is in the tray, placed upon the other bottom, _the tray will be filled up so as to leave a depth of a quarter of an inch only unoccupied_. This space I fill with the moistened star composition, having first rubbed the surface of the false bottom with soap to prevent any adhesion taking place between the composition and the wood. Having now pressed into the tray as much composition as will fill it to the height of its sides, I score it with the spatula as directed above. A large hole is made in the _natural_ bottom of the tray, so that I can, by putting my fingers through it, raise the false bottom covered with stars out of the tray. I then place a piece of cardboard or zinc on the top of the stars and turn the false bottom upside down. The stars will be found to separate from the wood very easily, and may be left to dry on the zinc. The tray is then ready for another batch of stars.

The advantages of this plan are, that there is no trouble in getting the composition into a uniform, convenient shape and thickness; that the composition requires much less gum-water; and that, consequently, the process is a quicker and a cleaner one.

TAILED STARS.

15. The same plan may be adopted also for the making of _tailed_ stars, with a slight variation which I now proceed to describe. These stars are not moistened with plain gum-water, but with a mixture of gum-water and linseed-oil. The gum-water should be of the strength given above, and should be made _quite hot_ by placing the bottle which contains it in a jug of boiling water. When it is sufficiently hot, _to every 8 ounces of gum-water add 1 ounce of linseed-oil_. Shake the bottle till these are thoroughly mixed, _and no oil can be seen_. Use the moistening fluid, _while_ hot, in the same manner as directed above for brilliant stars. The following is the composition for

TAILED STARS. Nitre 16 parts. Meal-powder 12 „ Antimony (sulphuret) 8 „ Fine charcoal 4½ „ Sulphur 4 „

If the above directions are carefully followed out, you will have some stars which are exceedingly beautiful in their effect, and by no means difficult to make. At its first appearance the star has nothing remarkable in it but the rapidity of its combustion. When this, however, is over, a kind of boiling lava is formed which remains red hot for a long time, and which, in its descent to the earth, takes the appearance of a glowing drop of golden fire, followed by a tail of sparks, remaining visible till it reaches the ground. I think the proportion of linseed-oil given above will not bear being altered without detriment to the performance of the stars. _If less oil is used, the stars assume their tailed form sooner, and disappear sooner; if more_, they will reach the earth before their principal and characteristic beauty is seen.

Both “brilliant” and “tailed stars” may be made in cubes whose sides are about a quarter of an inch. On account of the presence of the oil, “tailed stars” take a longer time to dry than “brilliant.” An advantage which they possess, besides that of superior beauty, is that they are much more sure of ignition than brilliant stars.

I may as well mention here that a tray for forming the stars, such as I have described above, and of the size given above, will contain about 8 or 9 ounces of composition at a time.

COLOURED STARS.

16. We now come to the very important subject of _coloured_ stars. These require considerable care in their preparation, the beauty of their performance depending entirely upon the _uniform fineness, the intimate union, and the dryness of their ingredients_. If you wish to make these coloured stars with any degree of satisfaction to yourself, keep the various preparations which enter into their composition _always ready for use_—that is, _in fine dry powder_, preserved in well-corked or stoppered bottles. There is one chemical salt which requires especial care in keeping, on account of its deliquescent properties—that is, of its tendency to attract moisture from the air; and unless this salt, which is _the nitrate of strontia_, be thoroughly free from moisture when used, it will produce no effect at all, except a needless waste of chemicals. I must therefore tell you that the formulas which I am about to give you will fail most entirely in your hands, unless you are very particular in this matter of dryness. Over and over again have I been led to condemn formulas for coloured stars and fires as useless or imperfect, for the sole reason that I did not then know how their ingredients were to be handled, and what care was necessary for the production of their intended effect.

In the first place I strongly recommend you to attempt to make no coloured stars _for rockets, except such as are made in the pill-box cases_, of which I have spoken before. These pill-boxes are made in the following manner:—Procure a piece of _straight_ iron rod, 12 inches long, and from three-eighths to half-an-inch in size; the usual size for this “former” is about seven-sixteenths of an inch. Now cut some cartridge paper into strips about 8 inches wide, and from 9 to 10 inches long; paste these strips all over, and roll them round the iron rod closely and neatly. When this is done, remove the case thus formed from the rod without tearing or breaking it, and set it aside to dry. When dry it will be very hard and stiff. It can then be cut, by means of a very sharp knife, into little lengths of half-an-inch each. These lengths are the open pill-boxes, into which your composition is to be rammed for _coloured rocket stars_.

In order to accomplish the filling of these cases with the least amount of trouble, procure a piece of stick, of a convenient length, and of such a size round that it will pass _easily_ into the pill-boxes. Next take a small piece of quick-match, about 1½ inch long, and pass it through the pill-box in such a manner that it may project beyond each end about half-an-inch (see Fig. 31). You will be able to steady the pill-box while filling it by holding it by these two ends of quick-match. The composition pressed into these boxes is always slightly moistened; and by this means, when once dry, will not be liable to be shaken out again. In making, however, any trials of your coloured star compositions _for your own satisfaction_ before making a large batch of stars, you had better press the composition in _dry_; by this means you will be able to see at once what their performance is worth.

[Illustration:

Fig. 31. ]

The fluid that I employ for moistening these coloured compositions is a solution of shellac in methylated spirits of wine. As shellac enters into the composition of many of these colours, it will not be necessary to make your solution a strong one. It should be of the thickness of the ordinary spirit varnishes, such as photographers use for coating their negative pictures. The exact strength is not a matter of any great importance, as long as you do not make the solution too rich in shellac; for by doing this you will impair the purity of your colour to some extent.

Remember that you must make these compositions _wet_. A very slight moistening is sufficient to make them _bind_ well when pressed into their cases.

The first colour of which I shall speak will be the red, or crimson. It is in the preparation of this colour that you must be most careful about _dryness_.

CRIMSON STARS.

17. The composition which follows is, in my opinion, the best for

CRIMSON STARS. Chlorate of potash 24 parts Nitrate of strontia 32 „ Calomel 12 „ Sulphur 6 „ Shellac 6 „ Sulphide of copper 2 „ Charcoal (fine) 2 „

This composition gives a magnificent deep crimson when burnt _at night_. Do not be disappointed, if, in your experiments _in the day-time_, the colour should not appear very deep.

Remember that there are two kinds of colours in pyrotechny, and that beyond a certain point it is impossible to amalgamate their respective qualities. The first of these two kinds is the colour _which has a considerable depth of tint, but which has not much reflective or illuminative power_. The other kind is that _which has a very decided, but not so deep, tint, and which is capable of surrounding itself with a luminous atmosphere of colour during its combustion—in fact, which has great brilliancy and power of illuminating objects_. Now the _last_ of these two kinds is the proper one to be employed for star purposes. We should never desire to produce a shower of dead-looking stars, however intense their colour might be. It is also an ascertained fact that the colour of stars always _appears deeper when seen from a distance_. Do not then be disappointed, I repeat, if the colour appears somewhat weak when you are making a trial of your composition _just under your eyes in the day-time_.

Now, with regard to the crimson star composition above, remember that I only say that it is one that succeeds _in my hands_. You may, perhaps, think it too rapid in its combustion, in which case you can increase the proportion of calomel, or decrease that of the chlorate of potash. The calomel has the effect of deepening the colour, but at the same time of retarding the combustion, and of weakening the illuminative power. The shellac must be in as fine a powder as possible; it has the effect of producing a rich, thick flame, and also of rendering more sulphur unnecessary. It also enables the composition, after having been wetted with the above fluid, to harden into a mass tolerably impervious to moisture. The sulphide of copper is used for the purpose of giving a very slight bluish tint to the flame, and thereby of neutralising any yellow that might impair the purity of the crimson, arising from impurity of the chemicals.