Part 7
Many attempts have been made to secure these metallic ingredients from corrosion. Some have stirred the filings in a varnish made of resin and spirit; others have shaken them about in powdered black-lead, and so coated them with this substance. But a coating of any kind is tolerably certain either to rob the spark, which each particle of metal should produce, of its brilliancy, or to render the composition during combustion very smoky, and so impair the intended effect.
By far the most successful preparation of steel and iron that I have noticed is the following:—A weak solution of asphalt in naptha is made, and the filings or borings are stirred about in this. When it is thought that they are thoroughly covered with it, the solution is poured off, and the filings spread out upon a paper to dry. This plan will protect them from rust for a little time longer than they would otherwise remain uncorroded. But still the best plan is to prepare the compositions as short a time as possible before they are to be fired.
The size that I recommend for cases which are intended to contain Chinese fire is that called the _two-ounce_ case. To make them, the same former may be used as was employed in the manufacture of Roman-candle cases already described.
The paper and imperial board may be cut of the following sizes. Open your sheet of paper, _of the 70-lb. thickness_, to its full size, and divide it into three pieces, as shown in the following woodcut, Fig. 41:—
[Illustration:
Fig 41. ]
Then open your sheet of imperial board to its full size, and divide it thus into nine equal pieces, Fig. 42.
So that by these arrangements one sheet of imperial board and three sheets of 70-lb. brown paper will furnish you with material for _nine_ cases, each of which will be about nine and a-half inches in length.
[Illustration:
Fig. 42. ]
[Illustration:
Fig. 43. ]
My plan for rolling the cases is that which I have described in paragraph 25, but which may perhaps, be rendered slightly more intelligible by the accompanying sketch. Having pasted one of my strips of paper and one piece of board all over on one side, and having brushed some paste over my metal former, I lay the former across the strip of paper about one-third of its whole length from the end nearest to me. I then double the one-third of the strip, pasted side downwards, over the former, on to the remaining two-thirds, Fig. 43, taking care that the edges of the one are even and parallel with the edges of the other. Then having made a crease in the upper fold just in front of the former, I put into this crease the pasted piece of imperial board, and roll up the whole together. It is necessary, however, _to paste the upper side_ of the fold of paper which you have made round the former. This I have always found a very quick, and easy, and perfect method of preparing cases of any kind. I trust that I have rendered my meaning plain, as I shall have occasion to refer frequently to this operation. The rolling board must, of course be used.
The cases when made are to be choked, _while wet_, precisely in the same manner as described for rocket-cases, only it must be remembered that their aperture may be almost choked up, because when it has been reopened by the point over which they are loaded, _it must not be more than one-third of the interior diameter of the case in size_.
Having described the manufacture of the cases. I now proceed to give the formulas for the composition of
CHINESE FIRE.
40. There are two sorts of this fire which are known by the names _red_ and _white_. The red is that which contains charcoal, and _therefore has some red sparks intermixed with those produced by the iron_; the white is that _the sparks of which are produced by the iron only_. It is my intention to give several formulas for this fire, in order that my readers may select for themselves, and use that which they find most successful.
No. 1. Meal-powder 16 parts Nitre 16 „ Sulphur 4 „ Charcoal (No. 2) 4 „ Iron borings 14 „
Or the following is quicker in combustion:—
No. 2. Meal-powder 16 „ Sulphur 3 „ Charcoal 3 „ Iron borings 7 „
Or,
No. 3. Meal-powder 8 „ Nitre 16 „ Sulphur 3 „ Charcoal 3 „ Iron borings 8 „
Or,
No 4. Meal-powder 16 „ Nitre 8 „ Sulphur 4 „ Charcoal 3 „ Iron borings 7 „
The compositions given above produce what is termed _Red Chinese Fire_, since they all contain charcoal. I have numbered the charcoal, because Mr. Bolton, 146, Holborn-bars, supplies three different degrees of fineness, the _second_ of which is proper for this purpose.
The following formulas will produce what is called White Chinese Fire:—
No. 5. Meal-powder 16 parts. Nitre 6 „ Sulphur 3 „ Iron borings 10 „
Or,
No. 6. Meal-powder 16 „ Nitre 4 „ Sulphur 2 „ Iron borings 6 „
Or,
No. 7. Meal-powder 16 „ Iron borings 5 „
It is an understood rule among pyrotechnists that the smaller the diameter of the case employed the quicker must be the composition with which it is filled; or, in other words, a quick composition which answers well in a case of small diameter will burn too rapidly, or explode, in a case of larger dimensions. My readers must therefore first determine the size of the case that they intend to use. It will not be well to adopt any size of case smaller than the _two-ounce_ for Chinese fire. If, however, the ¼ lb. size be chosen, I should recommend the compositions No. 1, No. 3, or No. 5. Nos. 2, 4, 6, 7 will answer very well in a case of the 2-oz. size.
But if it be thought advisable to have recourse to a case of the ½ lb. size, a still weaker composition will be required, in which case the following formulas may be used:—
No. 8. Nitre 16 parts. Sulphur 3 „ Charcoal 4 „ Iron borings 7 „
Or,
No. 9. Nitre 20 „ Sulphur 4 „ Charcoal 4 „ Iron borings 12 „
For general purposes, cases of the 2-oz. size will be found quite large enough, particularly when used in combination, and not fired singly.
The most effective of all the compositions that I have given is No. 7, which consists of meal-powder and iron borings only, but it is very rapid and fierce in its combustion, and will burst the cases into which it is put unless great care be taken in the ramming. A very little of the composition must be rammed at a time, in order to insure a thoroughly equal and solid compression throughout the case. If properly managed a two-ounce case filled with this composition will throw a very brilliant jet of large flowers of fire from eight to ten feet in height.
I have sometimes thought that the moistening of composition No. 7 with a little turpentine, so that it becomes less dusty, has the effect of preserving the iron or steel from rust to some extent. At all events, it greatly facilitates the uniform mixing of the ingredients. It must, however, be especially borne in mind that _neither spirits of wine nor gin must be used to moisten any composition containing iron or steel_.
The iron borings which Mr. Darby will supply are very effective for the preparation of Chinese fire.
You should take care that the other ingredients are thoroughly mixed before you add the iron borings, and then that the iron be equally distributed throughout the mixture.
The next operation is the filling of the cases. For this you will require some tools not before mentioned, which I will now proceed to describe.
You should get Mr. Newman to make you three solid drifts which will pass very easily into your 2-oz. cases. The first of these should be about _nine inches long_, the second about five inches long, and the third two inches long. These tools will always be found convenient for many purposes in pyrotechny, and not only for the filling of Chinese fire cases. The two longest of these drifts should be about _nine-sixteenths of an inch in diameter_; the third may be nearly five-eighths of an inch.
Your mallet should be, in the measurement of its head, five inches long and three in diameter. It should be made either of ash or beech.
In the next place you will require a block with a nipple and point, such as is drawn in the page of illustrations, figs. 44, 45 and 46. This may be made of wood, with its point only of metal; but I much prefer a metal nipple and point. Mr. Newman has made for me a set of nipples and settles in gun-metal, _all of which fit into the same block_. They answer all purposes, and take up very little room; whereas you will find a multiplicity of blocks very inconvenient, if your accommodation is as scanty as mine.
You must, of course, have a scoop of a proper size for filling 2-oz. cases, and this, I think, will complete your tools.
Your case must now be pressed over the point of your nipple, and by this means its aperture will be made of the proper size. You will find it very convenient to have a ring of iron fixed into your block, through which the case must be passed, which will steady it and keep it in a perpendicular position while being filled (fig. 47).
[Illustration:
Fig. 47. ]
And this is in reality more than a matter of convenience, for unless the case be perpendicular while the operation of filling is going on, the blows of the mallet will not have their proper effect, and the composition will not be thoroughly consolidated; or, what is worse, the neck of the case may be wrenched or injured in some manner, and will in all probability give way and burst upon the combustion of the composition.
Now drive in your composition, a ladleful at a time, and, after putting in each ladleful, give the drift twelve blows with the mallet. Fill the cases till there remains a space of _two inches only_ unoccupied at the end. Into this end put _a gun-charge and a-half_ of gunpowder. Then with a bradawl separate one or two of the inner folds of the paper of the case, and turn these down on the top of the powder.
My method of filling in the ends of the cases is the following:—Melt in an earthen pipkin a mixture of two parts of common resin and one of wax. This may be poured into the ends of the cases upon the paper that has been turned down. It will harden in a few minutes, and will be found to insure you a good report from the powder.
It only remains now to prime these cases. This is an operation requiring some care, although it may be performed in a very simple manner. If the point of your nipple is not too long—that is, is only long enough to _reach_ the composition _without penetrating it_—all that you need do is to press into the mouth of the case some meal-powder paste; but if a cavity has been left in the composition, this must be filled up before priming, or the case will inevitably burst.
It is an excellent plan to take for your first ladleful, not any of the compositions for Chinese fire, but a ladleful of some slower fire containing no iron borings. You may use a mixture consisting of
Nitre 6 parts. Sulphur 1 part. Charcoal 1 „
The advantage of attending to this piece of advice will be very apparent to you, and I strongly recommend the plan to your notice in the case of _brilliant_, as well as of Chinese, fires.
[Illustration:
Fig. 48 ]
Having now described the manufacture of the cases of Chinese fire, I shall proceed to point out to you some of the combinations in which they may be used. The simplest is the ordinary Prince of Wales Feather, the framework of which any blacksmith can make in thin iron rod, having a couple of holes drilled in it, through which screws may be driven to fasten it to your post. I give you two sketches (figs. 48 and 49), the former of which has, in my opinion, rather the advantage. The mouths of the cases must, of course, be connected with quick-match, so that they all take fire simultaneously. By having a framework made of iron it will be liable to no injury from the explosions at the end of the cases. The same framework may be used with three Roman candles, instead of Chinese fire cases, and with excellent effect.
[Illustration:
Fig. 49.—Prince of Wales’ Feathers. ]
[Illustration:
Fig. 50. ]
The next most simple combination is that which is called the Bouquet of Chinese Fire. It should be made with, at least, five cases, and will then be found very effective in its performance. Its framework is of very simple construction, and may be made in a few minutes by any boy. The accompanying sketch (fig. 50), will prevent the necessity of any further explanation.
A very pretty piece may be made, representing a tree of silver flowers. Procure a straight piece of deal of any length that you require (the length must be determined by the number of cases that you intend to use). This will answer for the trunk of the tree. To this nail some pieces of lath in the shape given in the adjoining woodcut (fig. 51). On each of these, and at the top of the straight piece, tie a case of Chinese fire, and connect all the mouths of the cases by means of quick-match. When ignited, this piece will present a very beautiful appearance, and may be made a highly satisfactory conclusion to a small exhibition.
[Illustration:
Fig. 51. ]
It is worthy of remark that all pieces in which Chinese fire is used should be raised to a considerable height from the ground, otherwise they will lose much of their beauty, for the sparks produced by the particles of iron are thrown much farther, and remain visible much longer, on account of their superior size, than those produced by steel, and if they have not a certain distance through which to fall, much of their effect will be thrown away. The post on which I fire nearly all my pieces _stands ten feet out of the ground_. It is made of deal painted with lead-colour, and is about three inches square. It can be taken down or put up at a moment’s notice, as it fits into an oak box sunk in the ground, of the same kind as those used in drying grounds. If you have a post of this kind made, see that the part which fits into the box is _not straight_, but slightly tapered. This will allow of a better fit, and enable you to remove it far more easily when required.
There are many combinations which it will not be at all necessary for me to notice here, for the firing of one of these cases of Chinese fire is not only a beautiful thing in itself, but is also very suggestive of different devices under which this valuable preparation may be employed. If any of my readers should hit upon any unusually good device I shall be glad to hear of it through the publishers of this book; and if my readers, in the course of their experiments, should stumble upon a really good plan for preparing iron borings and steel filings so that they become incorrodible, they will confer a great favour upon the pyrotechnic world by making it known.
Be sure not to forget to first ram into your cases half-a-ladleful of the preparatory fire given above: it will save you many a disappointment. If you prefer a composition a little quicker, add some meal-powder to it.
Having said all that is necessary to make the manufacture of Chinese Fire intelligible, I pass on to consider, in the next place, the subject of Brilliant Fire.
BRILLIANT FIRE.
41.—The points of difference between brilliant and Chinese fires are these:—
1st.—The sparks produced in the combustion of brilliant fire by steel filings are much whiter, but at the same time much smaller and shorter-lived, than those produced by iron borings in Chinese fire.
2nd.—The steel sparks are not thrown to so great a distance, on account of their superior weight and size; but they are much more numerous, and afford a rich tale, or “brush,” as it is termed, of glowing scintillations, rather than a gracefully-falling jet or fountain of large sparks. This very fact, however, of their not being thrown so far from the case out of which they are fired renders them capable of producing an effect in combination of which Chinese fire is incapable. The cases, when arranged in the position of the radii of a circle or spokes of a wheel, will throw a _perfectly straight_ brush of brilliant fire, which will, of course, much more closely represent rays of light emanating from a centre than any fire the sparks of which have a tendency to fall.
3rd.—Another point of difference between the composition containing iron borings and that containing steel filings is that the former should never be employed in the construction of pieces which have motion; for the very motion of the piece, or rather the increased impetus with which the particles of _iron_ are thrown out into the cold air, has the effect of cooling them so rapidly that almost all their beauty is lost. But this is not the case with _steel filings_: they seem almost unaffected by the rapid motion of the piece in which they are employed; and for this reason they possess an advantage which fully makes up for their being so much less showy in their performance than the iron borings.
The cases into which the composition for brilliant fire is rammed need not be so large as those employed for Chinese fire. I employ two sizes—the 1-oz. size for cases that are intended to turn wheels or any revolving pieces, and a smaller size still for those that are to remain perfectly stationary during their combustion.
The fault into which the young pyrotechnist is most likely to fall is that of using a power considerably in advance of his need. In order that you may not do this (for there is always fear of failure when you do), I recommend you _to use no cases for brilliant fire larger than the one-ounce size_. This, you will find, will give you a moving power amply sufficient for any wheels that I suppose you are likely to use, and particularly if you bear in mind the rule, that _increase of power is gained much more safely and much more effectively by an additional number of cases burning at the same time than by any additional force that you can get out of one case_.
The 1-oz. case, as you know by this time, is made round a former exactly half-an-inch in exterior diameter and 12 inches long. The paper for these cases may be cut precisely in the same manner as directed for Chinese fire cases. The imperial board should be cut thus (fig. 52), into twelve equal pieces. Take care that the _long_ side of the board is divided into _three_, and the _short_ into four.
[Illustration:
Fig. 52. ]
If, however, you think a shorter case sufficient, cut your sheets of paper into eight equal parts, thus (fig. 53), and your imperial board into sixteen pieces—that is, half the length of the strips of paper; this will give you cases about five and a-half inches in length. Both these divisions of paper and board are for the 1-oz. cases.
[Illustration:
Fig. 53. ]
I will now speak of the smaller sizes, which are used only in fixed pieces, and which are generally called on that account, for the sake of distinction, _fixed cases_.
The former for these is a metal tube 12 inches long and seven-sixteenths of an inch in exterior diameter. For cases of this size you may either use paper and board cut as directed above for the longer 1-oz. cases, or you may divide each sheet of paper into six strips thus (fig. 54), and each sheet of board into twelve pieces half the length of the strips of paper.
For filling either the 1-oz. or the fixed cases it will be evident that you must have at least two drifts for each size that will pass _easily_ into their respective cases—one about 9 inches long in its straight part, and the other from 2 to 3 inches in length.
[Illustration:
Fig. 54. ]
You must also have a nipple and point over which to ram each different size of case. The exact size of these nipples you will see in the pages of illustrations (figs. 45 and 46).
Use the same mallet and observe the same rules in filling these brilliant fire cases as in filling the cases with Chinese fire.
We are now ready for the compositions. The first given is by far the most beautiful, and most generally used; but being very rapid in its combustion, it must be very carefully and uniformly compressed in the case. No. 2 is of a much quieter character, and may be found useful for some purposes.
BRILLIANT FIRE. No. 1. Meal-powder 4 parts. Bright steel filings 1 part.
Or,
No. 2. Meal-powder 16 parts. Nitre 8 „ Sulphur 3 „ Fine Charcoal 3 „ Bright steel filings 10 „
Neither of these compositions should on any account be mixed before their preparation is absolutely necessary, for their whole beauty depends upon the brightness of the filings at the time of firing.
COMMON AND SPARKLING FIRES.
42. I will now give a few formulas for common and sparkling fires, which will in all probability be found very useful for jets and fixed pieces.
COMMON AND SPARKLING FIRES. No. 1. Meal-powder 4 parts. Charcoal No. 2 1 part.
Or,
No. 2. Meal-powder 16 parts. Nitre 8 „ Sulphur 4 „ Charcoal No. 2 4 „
Or,
No. 3. Meal-powder 16 „ Very fine glass dust 5 „
Or,
No. 4. Meal-powder 8 „ Very finely powdered porcelain 3 „
These four compositions will be found effective for many purposes, but should not be used in cases under the _one-ounce size_. Their great advantage is that they are not in the least degree impaired by keeping. They are to be rammed into the cases in precisely the same manner as directed for Chinese fire.
BRILLIANT FIRE.—EFFECTIVE COMBINATION.
43. But now to return to _brilliant_ fire. I will suppose you to be using some of the first composition given, and to have completed the filling of a few cases. Let us see what we can do with these to put them into effective combination.
[Illustration:
Fig. 54a.—Five-pointed star in brilliant fire. ]