PYROTECHNY. 



261 



n-uu-i-ii- are seen alternately, and in concentric order. This 

 "> firework is required particularly for illuminating a spe- 



V^* cies of transparent star, which will la- dMOfttwd I 



after; and to aid the understanding in its construction, 

 a plate of it is given. 



It may be made of any form or number of cases, but 

 it is necessary that both the wheels should be attached 

 to one frame, and work on a common centre, as the 

 leaders could not otherwise be made to communicate. 

 Both the wheels should also be of the same duration. 

 This may be managed either by making the composi- 

 tion of the inner one twice as slow as that of the outer, 

 or else by doubling the same cases in the inner. Thus, 

 it' the outer wheel consists of six cases in hexagon or- 

 der, the inner may have the same number disposed in 

 a double triangle. In uniting the leaders, care must 

 be taken that the tendencies of both wheels are pre- 

 served in the same direction ; and that we may render 

 the disposition of these more intelligible, we have 

 chosen a simple form on which to represent it. 



Of Combinations of Fixed Caset. 



Of combi- The forms into which these may be considered are 

 nations of almost endless, and there is indeed scarcely any limit 

 fixed cases, to them but the expence. We shall only here describe 

 a few of the most practicable, as from these the artist 

 may easily extend them to any number he thinks pro- 

 per by variously combining them. We have also given 

 figures of these, which will save a good many words in 

 the description. 



The general rules are alike applicable to all. For 

 some, such as all the fires which contain iron, the Cases 

 must be choked, as they must be considered as gerbes; 

 and these compositions must be varied with iron-fire, 

 and with common charcoal fire. They must also be 

 provided of two or three different lengths, and also of 

 different sizes, for the sake of varying the effects. Be- 

 sides these sparkling cases, there must be ready a num- 

 ber of cases, of different sizes also, of white and blue 

 lights, together with crackers, stars, serpents, and Ro- 

 man candles. With these at hand, the artist will be 

 able, in a very short time, to make up all the different 

 forms that he may fancy, instead of being checked in 

 his operations for want of materials. We need scarce- 

 ly say that various shaped frames will also be required; 

 but as all these are immoveable, there is no difficulty 

 in their construction. 



These combinations are generally made out of large 

 cases, seldom being formed out of such as are less than 

 an inch in diameter ; as, when upon a small scale, their 

 effects are not sufficiently distinct. Such cases are also 

 often required to be of an unusual length ; but as it is 

 not convenient to drive them longer than eighteen 

 inches, if more is wanted, it is better to join two to- 

 gether in the same manner as the cases of pin wheels 

 are united. But as such very long cases will not burn 

 out well when the orifice becomes too distant from the 

 fire, the paper case must be made so thin that it [will 

 burn down ; or, what is better, a part of it may be un- 

 rolled after driving. It is chiefly where a white light 

 is wanted to burn for a great length of time, that this 

 / precaution is required. 



It seldom or never happens that these combinations 

 are used alone. They are sometimes the termination of 

 some other simpler display, or else they form part of 

 some general system of mutations. In all cases, they 

 must be provided with a general leader for the purpose 

 of setting them on fire, independently of the particular 



ones which, by firing all the cases in their proper of 

 der, are to produce the intended figure in fire. If they 

 are to follow after wheels, as these cannot communi- 

 cate light to any thing, that leader must be in the 

 power of the operator ; otherwise it is fastened to the 

 end of the firework, of whatever nature, which it is in- 

 tended to follow. Hut the greatest care must b taken 

 in the adaptation and protection of these, that they may 

 not fail to communicate, and that at the proper time, 

 that they may not take fire accidentally from the sparks 

 which may be flying about, and that, when they do fire, 

 they may not burst in such a manner as to derange 

 themselves, or any thing about them. 



Geometrical Figures. 



The chief of these are crosses, triangles, squares, Geonetri- 

 hexagons, and octagons ; beyond which the figure* ap- eal figure., 

 proach too near the circle to produce a distinct effect, p^re 



In the cross, the four cases are disposed with their CCCCLZXIII. 

 mouths outwards ; and the effect of this firework is Fig. 1-5. 

 much improved, by placing a bright light or a small 

 wheel in the centre. Or else four lights may be at- 

 tached upon the cases, so that the same case may ap- 

 pear to be throwing out both the sparks and the light. 

 In many fireworks, this is a deception which may be 

 used with very good effect. 



The triangle, square, &c. all act on the same prin- 

 ciple, so that the same rules will serve for the whole. 

 Wherever there is an angle, two cases meet at that 

 point, so that their fires cross outwardly, these produ- 

 cing a variety of regular and pleasing figures. Thus 

 in the square, for example, they form four external 

 right angles ; in the hexagon, six triangles. 



All these admit of various additions, from the intro- 

 duction of wheels or of white lights, or of smaller cases 

 of sparkling fire ; some examples of which will be seen 

 in our figures. We shall content ourselves with here 

 describing one or two varieties, as specimens from which 

 the artist may easily learn to contrive many more. 



A hexagon may have a blue light fixed on each an- 

 gle where the cases meet, and another in the centre. 

 Or instead of the light in the centre, it may have a 

 small wheel. Wheels for this purpose are convenient- 

 ly made of simpler cases when the figure is single, as 

 they may easily be measured for the same duration as 

 the figure in which they are placed. Thus as the 

 whole hexagon can only burn as long as one of its cases, 

 a wheel that is formed of two cases crossing each other, 

 as in the table rocket, each of which burns at both 

 ends, and the two in succession, will last exactly as 

 long as the geometrical figure in which it lies. 



Instead of this arrangement, six smaller cases may 

 be placed within the centre of the hexagon, with their 

 fires directed outwards in form of a star. For this 

 purpose the mouths must be placed together, that all 

 the fires may appear to proceed from the same point, 

 or a light may be placed on this point besides. Or 

 else the cases may be fixed to the circumference of the 

 frame that carries the hexagon, so that their fires may 

 be directed inwards. The same principles may be ap- 

 plied to all the other figures, and with the effect of pro- 

 ducing different varieties of form ; as may easily be 

 imagined without the necessity of any further descrip- 

 tion. 



The Ostrich Feather. 



This is a very pleasing form of sparkling fires, and The ostrich 

 is generally used for terminating complicated fireworks feather. 



