Pyrotechny — Edition Insights

he 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.

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.

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.

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.

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.