Part 12

I trust that my readers will not be alarmed at the number of ingredients in the above formula. I can only promise them that the colour produced is an extraordinary one, and cannot be produced by ordinary means. You will observe that I have recommended 12 parts of sulphide of copper. This must be the _fused_ sulphide. Or you may substitute for it equal parts of Chertier’s copper and sulphide of copper, or equal parts of Chertier’s, or of sulphide of copper and fine black oxide of copper. The _arsenic_ employed in the formula may be either orpiment or realgar, but by far the best preparation of arsenic for this purpose is the _finely powdered metallic arsenic_. Formula No. 9 is one of my own introduction. It possesses the advantages of being perfectly safe, deep-tinted, and decidedly illuminative. But I do not pretend to say that it can ever be admired to the same extent with the red and the green fires. These latter will always take the precedence, for their effect at night is so thoroughly theatrical and surprising that no other colour, however beautiful or extraordinary, can hope to supersede them. I was once asked by a lady to make a _brown-coloured_ flame. The idea was so rich in theory that I never attempted to dissolve its charm by any failures in experimental practice. But had I succeeded to the utmost with this brown fire, no illuminating properties could ever have been obtained. One might as well have expected a good effect from a _black star_ or a _neutral tinted sun_.

RED FIRE.

58. We come now to the most telling colour of all—the red, or crimson as it is usually called. In the preparation of the _green_ fires the _purity_ of the nitrate of baryta is the most important consideration. In that of the red fires the _dryness_ of the strontia is the main point. This is most especially to be borne in mind, as success or failure depends upon it. A really good red-coloured fire is often the making of an exhibition or its redeeming point, but in any case it is a most important feature, and on that account is worth the expenditure of any trouble on its preparation.

I shall give several formulas for red fires, each having its own characteristic properties. You will have but to determine the particular description of fire that is necessary, and I think you will find all that you need among the following compositions:—

RED FIRE. No. 10. Nitrate of strontia 20 parts. Chlorate of potash 3 „ Sulphur 5 „ Antimony 2 „ Charcoal (fine) 1 part.

This formula gives rather a deep rose-coloured flame, and has a most intense illuminating power. But the composition is one on which the non-dryness of the nitrate of strontia has the most disastrous effects. It is, when properly prepared, a very useful composition for illuminating buildings, &c., &c.

The next is a slower composition, having decidedly more intensity of colour. It is a remarkably good composition, having considerable depth of tint, and a very fair amount of reflective power. Its proportions are these:—

No. 11. Nitrate of strontia 64 parts. Chlorate of potash 4 „ Charcoal (fine) 5 „ Sulphur 24 „

The next formula is one of very slow combustion, but of the greatest depth of colour. It has but a small illuminating power, and can therefore be employed only for certain purposes.

No. 12. Nitrate of strontia 48 parts. Chlorate of potash 4 „ Sulphur 12 „ Calomel 8 „ Chertier’s copper 2 „ Charcoal (fine) 1 part.

This composition, burns so slowly that if it be very much compressed, or its case be at all thick, much of its effect is lost. I should therefore recommend that it be laid in a heap upon a tile in order to be fired. Its beauty will then be seen to the greatest advantage.

The following composition for red fire is the one which I have always found the most generally useful:—

No. 13. Nitrate of strontia 70 parts. Chlorate of potash 6 „ Sulphur 24 „ Charcoal (fine) 2 „ Shellac 2 „

This composition, when employed in a case 1¾ inch in diameter, produces a magnificent effect, and is at the same time a very economical composition to make up. Its combustion does not appear rapid, and yet there seems to be no lack of illuminating power combined with intensity of colour. It is, of all the compositions which I give, the one best adapted for the use of young aspiring pyrotechnists, as very certain in its results, very inexpensive, and very easy to prepare.

Thus we are brought to the close of our list of compositions for Coloured Bengal Fires. I trust that this list will be found to contain all that you require, and contain it, too, in variety and abundance.

But we have still to consider how these compositions are to be encased and fired.

COLOURED FIRES (To Encase).

59. The cases, made as directed above, I will now suppose to be dry and ready for use. Your drift, with which the composition is to be compressed into the cases, is one-sixteenth of an inch smaller in diameter than your former. It will therefore pass easily within the cases which were made upon “the former.” Now cut some pieces of newspaper, or thin brown paper, into squares or circles about 3 inches in diameter. Place the flat end of your drift in the centre of these, and turn down the papers round its sides in the same way that papers or bladders are turned down over bottles or jars when these are to be capped or covered. Then insert the drift with the paper cap over it into one end of the coloured fire case and push it through to the other end. Now withdraw the drift, and leave the paper cap in the end of the coloured fire case. Next place the case upright upon your driving-block with the end, thus filled up, downwards, and put into it as much powdered clay as will, when driven, occupy about half-an-inch in the end of the case. Drive this clay down firmly with a few blows of the mallet, taking care, however, not to rupture the case by exerting too great a force.

The case is now ready to be filled with composition. This operation is to be done as follows:—First put in enough of the composition to occupy about half-an-inch in the case, and ram this down with a few light blows of the mallet. Then put in another quantity, and ram that down in the same way; and so on till the case is filled. I strongly recommend you not to put in more composition at a time than will ram down into the space of half-an-inch. You will find it easy to compress the whole of the composition equally and uniformly by attending to this simple piece of advice; and you will soon discover, if you do not already know, the advantage of uniform compression.

When you have charged the case as far as you can with the drift and mallet, that is, to about a quarter of an inch from the top of the case, press the mouth of the case into the composition (from which you were filling it) until the case becomes full up to the brim. Over the flat surface of composition thus left, paste a piece of touch-paper, or any thin paper, taking care not to paste that part of the paper which lies against the composition, but only that which is to stick to the sides of the case.

COLOURED FIRES (To Fire).

60. Your coloured fire is now complete and ready for firing. This is the usual and most convenient way of preparing colours for exhibitions. But for your own experiments you may place a small quantity of the composition to be tried upon a tile or brick, not spreading it about, but piling it into a pyramidal heap, to be lighted at the top. Many persons adopt this plan for exhibitions, but it is not good, because several of the best compositions burn too rapidly when unconfined by a case. I only beg that you will do me the justice to remember that the formulas which I have given above are intended to furnish compositions suitable for burning in such cases as I have described, and not, as a general rule, adapted for open and loose burning. My plan all along has been this—to find compositions of sufficient freedom of combustion to enable them to consume their case, to give a powerful light, and not to burn out too rapidly. I think I have succeeded in gaining the first two of these qualities in the compositions themselves, and the third by compressing them closely in cases.

It is very much better to put into each case two different sorts or colours of fire, making the fire, for instance, change from white to red, or from green to purple. But if this be done, and more than one case is to be burning at a time, of course an especial regard must be had to the contrast of colour. You should never burn a yellow with a red fire, or a yellow with a white; green with red, yellow with purple, white with red make the best contrasts.

But, for my own part, I never burn two Bengal fires of different colours at once. If the fires have any illuminative power at all, they are pretty certain to neutralise one another’s effect, and so give you a very poor and unsatisfactory return for your outlay. It is very true that red and green are _complementary_ colours, as they are called, and look very well side by side, but the effect produced upon an object by illuminating it with a red and green light is anything but complementary to the object or to the coloured fires themselves. If you wish, however, to try the effect of the contrast, use compositions possessing the greatest depth of colour and the least reflective power; in this case the fires themselves will be complementary one to another, and their non-illuminative properties will effectually prevent any confusion of reflection. That what I have said above is true any one may discover by getting two pieces of stained glass, one of a rich red, the other of a rich green colour. Let these colours be thoroughly _transparent_, and if you place one before the other and attempt to look through them, you will find that you have a medium through which very little can be seen at all.

The cases of coloured fire, made as directed above, must not be placed perpendicularly to be fired, but _horizontally_. The reason of this is very simple. While they are burning a sort of boiling lava is formed, which is the refuse of the combustion, and this will considerably clog the flame and rob it of much of its light if allowed to remain at the mouth of the case. Now if the cases be placed horizontally, this lava will fall away as it forms, and leave the fire to burn without impediment.

All that it is necessary to do to give the cases this horizontal position is to drive two long, stout nails into a post horizontally, about an inch and a-half apart, and lay the case on these. Coloured fires should, as a general rule, be fired at a distance of about three or four feet from the ground.

But as one cannot always find nails of the proper sort for these purposes, especially when at a distance from one’s own stores, I have sketched for you an iron which I always use, fig. 91, and which I am sure you will find convenient. It is made in the shape of a tuning-fork, with a screw at its handle; this screw is simply twisted into a gimlet-hole in a post, and is easily put up or removed.

I must not omit to say a few words with regard to the placing of coloured fires. This must depend mainly upon individual taste, but a few hints may not be out of place. I cannot help thinking that the best and most effective way of displaying coloured fires is _to conceal the fire itself, and let only its illumination or reflection be seen_. Let any of my readers keep his spectators at a distance of twenty or thirty yards from the coloured fire, and hold up a tray or piece of board in front of the fire, of such a size as will conceal only the fire itself. I think it will be generally admitted that the beauty of the piece is much enhanced by this simple contrivance, and if it be thought so, then it becomes a consideration whether it would not be better to use the most illuminative colours always out of sight, in such a position that their effect only can be seen. For instance, if there be a large tree conveniently at hand, place your colour on that side of it which is away from the spectators, so that the trunk of the tree is between them and the coloured fire. This plan I have always found to give a most charming result.

But it must be remembered that anything but highly illuminative colours cannot be employed in this manner. You will of course find objectors to the plan mentioned above. There are many people who will tell you, “No, I like to see the light itself,” as if gazing on the sun or moon, except for astronomical purposes, could ever give half the pleasure that the sight of a fine sunlit or moonlit landscape can impart.

What would a fairy scene in a pantomime be worth if you saw some of the green-room myrmidons, with a pot of beer in one hand and a lucifer-match in the other, lighting a heap of composition on a tile beside the stage, and then saw the composition burst into a smoky flame, but were prevented from seeing the effects of its colour?

This suggests to me another branch of my present subject, which some of my readers may consider an important one.

COLOURED FIRES FOR THEATRICAL PURPOSES.

61. In the event of private theatricals you may not, or your friends may not, like their drawing-room to be filled with a strong sulphurous smoke, which is pretty certain to hang about the drapery of the room and the dresses of the company for some unpleasantly long time. I shall therefore give you now two or three formulas for coloured fires which may be safely used in a room, and which contain no sulphur.

But first let me give you this caution, which it is most highly important that you should attend to:—

NEVER BURN ANY COLOURED FIRE COMPOSITION INDOORS, OR IN ANY INCLOSED SPACE, WHICH CONTAINS ORPIMENT, REALGAR, OR ANY PREPARATION OF ARSENIC AMONGST ITS INGREDIENTS. THE FUMES FROM SUCH COMPOSITIONS MUST BE VERY INJURIOUS. THEY CAN ONLY BE USED WITH SAFETY OUT-OF-DOORS.

COLOURED FIRES FOR THEATRICAL PURPOSES. WHITE. No. 14. Chlorate of potash 12 parts. Nitre 4 „ Sugar 4 „ Stearine 1 part. Carbonate of baryta 1 „

This does not give a pure white light, for it is impossible to get a real white without sulphur, but when used to overpower theatrical lamplight, it is to all intents and purposes white.

YELLOW FIRE. No. 15. Chlorate of potash 6 parts. Nitre 6 „ Oxalate of soda 5 „ Shellac 3 „

Nitrate of baryta may be substituted for nitre in the above formula with advantage, provided it be very dry and fine.

GREEN FIRE. No. 16. Chlorate of potash 2 parts. Sugar 1 part. Nitrate of baryta 1 „

This green colour is but faint in itself, but gives a very good reflection.

RED FIRE. No. 17. Nitrate of strontia 4 parts. Chlorate of potash 1 part. Shellac 1 „

These colours are for the most part very rapid in their combustion, and therefore may be used in cases if you please. But as coloured fires for theatrical purposes are only required to last a short time, the more brilliant they are during that time the better.

CHINESE FLYERS OR SAXONS.

62. I now treat of the manufacture of Chinese flyers, or Saxons, as they are called by professional pyrotechnists. But it will not be sufficient merely to speak of the manner in which they are made—we must follow them into some of those combinations in complex designs in which they fulfil a very striking part.

And first the object of the Chinese flyer is to produce a circle of white fire, unattended by any scintillating radii, which can be easily worked into large pyrotechnic designs, and which is at the same time easy of construction.

The Chinese flyer forms a very pretty little piece of itself when properly made, but its principal use is in combination. It is of two kinds, and these are known by the names of the “single” or “double” Saxon or flyer.

[Illustration: [Fleuron]]

SINGLE SAXON FLYER.

63. First we will speak of the single Saxon. Its case should be eleven inches in length, and should be made round a “former” of the one-ounce size. In order to cut your paper and board of a proper size for these cases, refer to the following woodcuts. Open a sheet of 60 lb. brown paper of the imperial size, and divide it in halves lengthwise. At fig. 92 it will be seen that each sheet of paper will give you two cases. If you use 70-lb. brown paper instead of that of the 60 lb. substance, you will hardly require any imperial board. But I think that the cases are better when made with a piece of the board used with the paper. Supposing, then, that you employ 60 lb. brown paper, cut your imperial board as shown at fig. 92a, that is, into eight equal pieces, one of which is to be used with each strip of paper.

[Illustration:

Fig. 92. ]

[Illustration:

Fig. 92a. ]

Now paste your paper and board well all over, for you will require a hard, strong case. Then proceed to roll your paper round the former, folding it over in the manner described at par. 39. Then place upon the unfolded paper the piece of imperial board, and roll both up together into a close firm case. Your former should be moistened with paste, and particular care must be taken that the inner fold of the paper, that which lies next to the former, is well saturated with paste. This will effectually prevent its being separated afterwards when dry, and will obviate one cause of failure and explosions. I have before explained the necessity for attending to this piece of advice in speaking on tourbillons. The cases for these Chinese flyers are, in fact, very much like those made for Roman Candles, but as they are to contain a very much stronger composition, must have so much additional care bestowed upon their preparation.

The next thing necessary is to know the principle upon which these Chinese flyers are made. A reference to fig. 93 will make this easily intelligible. The composition is rammed into the cases in two compartments, between which and at the extreme ends of which some dry powdered clay is driven in. The clay in the centre of the case is put there to form a solid substance, through which a hole can be bored to admit the spindle on which the case is to revolve. The clay at the extremities of the case is driven there to form a hard ending which is capable of resisting the force of the combustion of the composition. The intervening spaces between the ends and centre of clay are filled with composition.

The cases are filled over a settle proper for the purpose, of which a sketch is given at fig. 104. When the cases are dry, take one of them and place one of its ends over the projecting piece at the top of the settle. You will now require a long drift, rather less than half-an-inch in diameter, so that it will pass easily in and out of the case. It must, of course, be of a length not less than that of your case. I must suppose that you provided yourself with a ladle proper for filling the cases of brilliant fire, and the wheel-cases, of which I have treated. The same ladle will now come into use again. In case you have not such a ladle, buy or make yourself one in metal which will pass easily into cases of the one-ounce size. In this ladle take up as much powdered clay as will, when driven, occupy a quarter of an inch in the length of the case. Drive it in firmly by means of your drift and mallet. Then put in the composition, for which the following are the formulas:—

COMPOSITION FOR SAXONS. Meal-powder 16 parts Nitre 8 „ Sulphur 6 „

Or,

Meal-powder 6 „ Nitre 3 to 4 „ Sulphur 2 „ Antimony 2 „

Of these two I prefer the former, but the latter is perhaps better when the flyers are to to be fired singly, as it produces a much greater halo of sparks.

Now drive in the selected composition, a ladleful at a time, giving from twelve to sixteen blows to each, until it rises to half-an-inch below the middle of the case. It is a good plan to mark cases, so that there shall be no possibility of mistake as to where this point is. Remember that you will require one inch of clay in the exact centre of the case, in the middle of which clay you will have afterwards to bore a hole. Upon the top of this clay ram in more composition until the case is filled to about three-eighths of an inch from the end. Upon this second composition drive in as much powdered clay as you drove in at the other end of the case, taking care that it is made very firm, and is not at all likely to be blown out by the combustion of the composition.

The next thing to be done is to bore the central hole through the clay. I do this generally with a bradawl first, and afterwards with a pin-bit or spoon-bit. The size of spindle which is best adapted for such fireworks as these is that which is three-sixteenths of an inch in diameter. I should therefore use a bradawl of about an eighth of an inch in diameter first, and then a pin-bit of the same size as the spindle to be employed. Care must be taken that the hole is not made unnecessarily large, and that it is bored at right angles with the length of the case.