Part 2

But before concluding this part, I would impress upon the amateur the advantages to be derived from adopting a fixed plan of operations in preparing for his exhibition. If he would do his work well, he must learn to do it with the greatest economy of time, and labour, and material. He should first decide of what pieces his exhibition is to consist; next he should get all his cases made, and remember that these are not to be used until they are thoroughly dry, and that the more gradually and naturally they are allowed to dry the better they will be for his purpose. He should commence the filling of one kind of piece, and finish all of that species up to a certain point, before he begins upon any other kind. He should calculate the quantity of composition necessary for them, and not mix it until the cases are ready to receive it, and he has time to fill them. A very little practice will enable him to judge correctly the quantity necessary; but let him not hurry over this part of his work, for a very slight inaccuracy in reckoning the quantities of the several ingredients may spoil a large batch of composition. The old proverb, “The more haste the less speed,” is at least as true in the practice of firework-making as in any other work. By mixing up no more composition than he really requires, he will both avoid waste and have no odds and ends of combustible mixture to take care of. He may perhaps think this piece of advice very unnecessary, but he will soon arrive at the conclusion that it is well worth his attention. Let him also bear in mind that he will require to get out as many tools for the making of one rocket as of ten, and that when he has them to his hand he cannot do better than finish the ten.

It is not, of course, to be expected that the amateur will at first fall naturally into the most easy and convenient methods of working, but every additional hour’s practice will furnish some new experience, and he will soon discover that those operations, which at one time he considered the most troublesome and difficult, can be successfully performed in some very simple manner. He must never go to work under the idea that there is but one way of carrying out his plans; the exercise of a little thought on his part will generally unfold to him ways and means of accomplishing his object satisfactorily and with ease. It is always best for each operator to establish his own mode of working, and not always to attempt to carry out details of manipulation which he sees described, under the impression that what is thus recommended is _the_ way.

[Illustration: [Fleuron]]

[Illustration: [Fleuron]]

PYROTECHNY.

GENERAL OBSERVATIONS.

I must beg of you, kind reader, the privilege of addressing you no longer in the third but in the second person. By speaking to you, instead of about you, I shall avoid much circumlocution, and in words, at least, identify your interests with my own.

Since “generals” take the precedence of “particulars,” before entering upon any description of the details of _rocket_ apparatus or manufacture, I must introduce you to certain friends without which you will find it difficult to get on in your work, and with which I trust you will shortly be on excellent terms, for you will require their aid in almost every branch of pyrotechny. The tools peculiarly employed in each separate process of the art will be spoken of in dealing with that process, and in their own place; but a short account of the things that are _generally_ requisite will be more in place here than in any other part of this work.

SCALES AND WEIGHTS.

1. In the first place, some are indispensable. The scales that I use are of a very common make, with copper pans capable of holding about four ounces of nitre. These I have always found very convenient, and they are by no means expensive to buy; but I should think there is hardly a house where such a pair would not be found ready to hand. I use also, for purposes in which more delicacy and exactness is required, a pair of grain scales such as are employed by the apothecary. It is very important, particularly in the preparation of coloured fire compositions, to be very exact in weighing out those ingredients which enter sparingly into the formulas, for a little more or less of these will often change entirely the character of the composition.

And now let me say a few words upon the subject of _weights_. The old books on pyrotechny did their best to confuse their readers in many ways, but in none more successfully than the following:—They insisted on giving their formulas in _weight_. For instance, they would tell you to mix together 3½ oz. of one ingredient, 2 dwt. of another, 1 scruple of another.

Now the ordinary way in making up such a receipt would be by employing one weight out of three distinct tables, for the ounce usually employed in commerce is the avoirdupois ounce; the pennyweight is only found in a table used for weighing precious metals and precious stones; the scruple only in a table used by a compounder of medicines. Now I intend to avoid all confusion of this kind by the simple plan of giving my formulas in _parts_ and not in weights. For instance, in writing down the formula for gunpowder, I should put it in the following manner:—

Nitre 70 parts. Sulphur 15 „ Charcoal 15 „

So that, whether you take it in grains or in tons, the formula is equally intelligible, and you get at one glance a true idea of the relative proportions of the ingredients. But, although I mean to keep weights out of my formulas, we cannot dispense with them in our work. Now, if you would save yourself much trouble and inconvenience, procure, in addition to your ordinary grain weights, a 2-oz., a 1-oz. and a ½ oz. _troy_ weight. This ounce contains precisely the same number of grains as eight of your apothecary’s drachms and as twenty-four of your apothecary’s scruples—that is 480 gr., whereas the avoirdupois ounce contains only 437½ gr. And by this means you will avoid much confusion and save much time in your calculations; because you will have all your smaller weights convenient aliquot parts of the greater; and, if I mistake not, you will find these extra weights very handy for other than pyrotechnic purposes.

Next, I wish to caution you against an injudicious employment of the pestle and mortar. These auxiliaries are not intended for any other purpose but the reduction to powder of lumps, crystals, &c.; they are never properly used for _incorporating_ ingredients. _Large_ quantities of pyrotechnic compositions are always _mixed_ in a sieve; _small_ quantities are best mixed by stirring them about with a spatula upon a piece of paper. A pestle and mortar is a species of apparatus which I rarely use, for I procure my various salts, &c., in the form in which they are ready for use, and I strongly recommend you to do the same, feeling that you will soon be convinced of the convenience of such a plan. Remember, too, to keep your powdered ingredients in well-corked or stoppered bottles, for the reason that some of them are very deliquescent, and are utterly unfit for pyrotechnic purposes except when perfectly dry. The four following things, however—nitre, sulphur, charcoal, and meal-powder—which are not subject to injury from a slight exposure to the air, and which will be required in larger quantities than other things, I always keep in tin canisters, such as are made to hold a pound of coffee. A piece of sheet copper about six inches long, bent into the form of a shallow boat or scoop, will be found useful in taking these things out of their canisters to be put into the scales and weighed.

SIEVES.

2. Now with regard to SIEVES: you will require two of these, with brass-wire bottoms; one of the fineness of twenty meshes to the inch for _mixing_, which, for distinction’s sake, I will call _the mixer_; the other of forty or fifty meshes to the inch for _sifting_, and to which I shall refer as the _sifter_. These sieves are made with a receiver and a top, so that by their means you can sift or mix any compositions, however subtle or dusty may be their nature, without the slightest inconvenience or annoyance. I may as well here mention that I use the 20-mesh mixer for _sifting_ the _coarse_ charcoal employed in my rocket compositions, but all other sifting is done by the 40-mesh sifter. The size of those which I use is about six inches in diameter, and I think you will find this large enough for every purpose, as you will not be likely to want to mix or sift any very large batches of composition at a time. These sieves, made of any size or design that you please, may be procured of Mr. Darby, 98, Regent Street, Lambeth, London, at whose shop you will also find many other handy little articles, such as horn or copper scoops, spatulas, &c.

[Illustration: Fig. 34. Fig. 35. Fig. 37. Fig. 38. Fig. 39. Fig. 40. Fig. 44. Fig. 45. Fig. 46.]

MANUFACTURING.

ROCKETS.

3. Having now cleared our way of these necessary preliminaries, we may at once proceed to speak of the manufacture of ROCKETS; first, of what a rocket is, and then of how it is made. There is nothing like starting with a good distinct notion of what we have to make before we set to work to make it. It is said of a person who was asked by his friend to give him a logical definition of a house, that he at once replied that “_it was a thing with a chimney_;” which definition, being equally applicable to a moderator lamp and a steam-engine, can hardly be considered exhaustive in the case of a house; and, in like manner, if we start with the idea that a rocket is _a thing that goes up in the air_, we shall not have any very tangible model of rocket excellence before us as a guide in our work. It is, however, very true that some rockets which we see can only be properly and faithfully described as things which go up in the air, for they no more deserve the name of a rocket than does a child’s kite or a cock-sparrow, either of which would come equally well under the above definition. But let us see whether we can arrive at something a little more accurate. A rocket we will define as _a species of firework which, when properly fastened to a stick of a certain size and weight suspended with its mouth downwards, and ignited, ascends into the air by the force of its own combustion, rises majestically to its proper height, throwing out, from the beginning to the end of its course, a rich and uniform tail of sparks, and at the extreme range of its flight giving birth to a cluster of stars, or shower of fiery rains, or other decorations, as they are called, which should burn long enough to be well seen, and not disappear almost at the moment of their appearance_. This is what every rocket should be when fired; and let me beg of you not to stop short of attaining this excellence, for perseverance will give you experience, and with the aid of these two you need despair of nothing. When I had been puzzled and misled by all the books and information on the subject that I could procure, and had met with nothing but failure in all my attempts, I set myself to work to make my own experiments in a new direction, on the supposition that I understood, to a certain extent, the principle on which success depended. And well do I remember my delight at seeing a rocket of my own production scramble up into the air in a very undignified and disorderly manner, and there perform certain nervous evolutions which I will defy any pen to describe or pencil to depict. But although its performance was erratic and laughable, I had conquered; the key from that moment was in my own hands; and soon, after careful consideration and a few more experiments, I managed to produce a rocket of which I saw no reason to be ashamed.

I have stated above what appearance a good rocket should present to the eyes of a spectator when fired; I am now about to state what appearance it should present to its manufacturer before being fired—in fact, what it is that he has to make. _It is a strong cylindrical case, made of pasted brown paper and imperial board, contracted near one of its ends in order to form a narrow aperture, and filled with a certain composition in such a manner that a long narrow cavity is left in its centre, extending almost throughout its whole length._ This is what I shall call the rocket, for the ascending power lies solely in this part; the head, being an after-addition, will be spoken of it in its proper place, and not allowed to interfere here. In the annexed woodcut A A represents the exterior diameter of the case; B B, the interior diameter of the same; C C, the long cavity extending from the mouth up the centre of the composition, which cavity is called the “soul” of the rocket; D D D, the composition with which the remainder of the case is filled. The lower of the two C’s represents the mouth, or “choke” as it is called, at which all the combustion that goes on in the rocket has to find its vent. When a light is applied to the mouth of the rocket, the whole surface of the soul of the rocket is set on fire at once, and on this depends its power of ascent; for so large a quantity of fire having to make its escape through so narrow an aperture and meeting with considerable resistance from the external air, makes the rocket recoil in a direction opposite to that of its mouth, until all the combustible material which it contains is consumed. This is a broad outline of the principle upon which rockets ascend. It will be unnecessary for me to dive deeper into theories here, for I am sure that you will be anxious for me to come to practical details without further delay.

[Illustration:

Fig. 1. ]

Among other things in my prefatory remarks I stated that firework-making need not be an expensive recreation, but you must bear in mind that nothing is easier than to make it expensive, and that we must adopt some strictly economical system of operation. Since rockets are the most scientific of all fireworks, and the apparatus necessary for making them is more costly than that for making any other kind of firework, we must do all that we can to bring their manufacture within reach of the amateur. There are many books, and I dare say many persons, that will tell you that you cannot hope to produce a good rocket unless you have a mould proper for the purpose made either of gun-metal or of some hard wood. I believe that I am right in telling you that such a piece of apparatus varies in cost from 3_l._ to 10_l._, but I also know that I am right in assuring you that a rocket, in every respect equal to many that are rammed in a mould, may be produced without this expensive luxury. I can only say that I _never_ use a mould, and my belief is that the workmen employed by professional pyrotechnists are, for the most part, only too glad to dispense with its use, for it is of importance to them to ram the greatest possible number of rockets in a given time, and if they were to be delayed by having to unscrew and screw a mould before and after filling each case, half their time and its value would be lost to them. I use, and recommend you also to use, a simple steel spindle let firmly into a wooden block, and if your cases are made strongly enough you will be able to produce all that your ambition will picture to you by means of this inexpensive apparatus, and without the help of the mould.

But before we speak of the size and proportions of this spindle it will, of course, be necessary for us to determine the size of the rocket which we intend to produce. Now, the rocket that I recommend you to make, as being the most generally useful and economical, is that which the professionals call the _¼lb. rocket_. You will bear in mind that this name is not intended to signify that the rocket when finished will weigh a quarter of a pound, but that its interior diameter is equal to the exterior diameter of a leaden ball weighing 4oz. You will find, I am sure, that the capabilities of this size of rocket, when properly made, will satisfy you for all ordinary purposes, and, taking this for granted, I shall now proceed to speak of this particular size only, in order to prevent the possibility of confusion.

ROCKET-CASES.

4. The first thing that you have to do is to make the case. Do not hurry over this part of the process, for more depends upon it than is generally supposed. It is made in the following manner:—Procure some imperial board (which is a kind of thin pasteboard made of two sheets of brown paper pasted and pressed together); also some stout Kentish brown paper of such a substance as will weigh 70-lb. per ream. Now fold a sheet of the imperial board down the middle of its length, thus:—

Cut it along this fold, then divide each of these halves crossways into five equal parts and cut them apart. Each sheet will thus furnish enough board for ten ¼lb. rocket-cases. This board is only made in one size. Now take a sheet of the 70-lb. brown paper, divide it into halves at its natural fold, and then divide each of these halves crossways into four strips. One of these, together with one of the strips of imperial board, will be sufficient to make one case. I have given you above the directions for cutting your paper and board without waste; you will, however, find it more convenient to buy them ready cut up; it will save you time and trouble, and will occupy much less space among your stores. They can be procured of Mr. W. H. Darby, 98, Regent Street, Lambeth, London, and he will supply them ready cut if you only state for what purpose they are intended.

[Illustration:

2 ]

The “former,” on which the board and the paper are to be rolled, is simply a piece of brass tubing, about 12 in. long, and ¾in. in diameter. This you had better procure of the person whose name I shall mention presently, when I speak of apparatus, and to whom I recommend you as a maker of all pyrotechnic _tools_, except such things as the sieves, &c., above mentioned.

I must not speak about the pasting and rolling of the cases until I have said a few words upon the subject of the paste itself. It is a great mistake to have your paste made thick; you will gain nothing by doing so, and you will find it very troublesome to use. It should be made of such a consistency as will admit of its being spread very readily upon the brown paper, &c., and by being tolerably fluid will saturate it much more thoroughly; and this, after all, is what you want to do, for the hardness of the finished cases depends far more upon the complete saturation of the paper than upon the thickness of the paste between its layers. The brush, which you will find convenient, is one about 2in. in diameter, and can be procured of Mr. Darby. Into each pint of paste, while boiling, put a large teaspoonful of powdered alum; this will have the effect of keeping your paste sweet and free from mouldiness for weeks, and will also prevent it from becoming watery, which it would otherwise do in a few days.

I will now suppose you to have your paper, imperial board, paste, and brush ready to hand. You will next require some kind of slab on which to paste and roll your cases. For this purpose I use one of the largest common roofing slates that can be procured: its size is 24 by 12in. This makes a cheap and very serviceable pasting slab if its surface be only moderately smooth.

Now we come to the actual rolling of the cases. First paste all over one side of one of the strips of 70-lb. brown paper; then take one of the strips of imperial board, and fold one end of it once round the brass tubular “former.” Hold this, thus folded, with your left hand, and paste over all the rest of the upper side of the strip with your right. Then roll it up, as straightly and as tightly as you can, till all but about 3 inches of it is wound upon the “former.” Upon these projecting 3 inches lay the end of the strip of brown paper, with its pasted side upwards, and then roll it till both board and paper are neatly and closely wound round the “former.” You will find at first a little difficulty in getting the strips to roll up straight, but a little practice will overcome this. You will now require what is called a “rolling board,” that is, a piece of common smooth deal board about 20 inches by 8 in size, with a wooden handle screwed on its upper side at one end (see fig. 3). Then with the left hand take hold of the end of the “former,” which projects out of the case, loosely, so as to allow it to revolve in the hand, and with the right hand roll case and “former” from one end of the slate slab to the other between it and the rolling board, pressing upon the latter, and using it as a carpenter does his “trying plane;” and by this means the same effect will be produced upon your newly-made case as is produced upon linen, &c., by a mangle. These directions read, no doubt, as if they belonged to some very complicated operation; but let me assure you that it is one far easier to perform than to describe. Some modification of this plan will in all probability suggest itself to your mind as an improvement upon it; for there are few people who do not after a few trials fall into some method of working which, besides answering their purpose, has the additional merit of being peculiar to themselves. I may as well mention here that the quickest way of making cases is to paste all your strips of paper and board before you begin to roll any of them, taking care not to paste that part of each strip of board which is to make the first turn round your “former.”

[Illustration:

3. ]

[Illustration:

7 ]