PY ROT ECU NY. 



Tyrotech. places, that the artist may himself light them when the 



pr >|HT time is arrived. 



^"Y"" 1 Now as fire can be conducted from one fixed piece 

 to another, so it may from fixed to moveable ones 

 through any motif of succession that may be requisite. 

 The leader from the last fixrd piece may, for example, 

 ittactuul to the first case in a wheel. To this it 

 must be fixed in such a manner, thut the first lighting 

 of the wheel may burn and separate the connection by 

 which the wheel was kept steady in its place. This is 

 easily managed by means of cotton quick-match, which 

 is sufficiently strong to support any thing very firmly, 

 but which is burnt and detached in an instant. But 

 it is not possible to communicate from moving to fixed 

 pieces, as is easily understood. A separate leader 

 is therefore required for all these communications, 

 which is carried away out of the risk of casual fire, and 

 brought under the command of the artist who directs 

 the work. 



Of Machinery, Frames, and Transparencies. 



Of machin- Although many of the motions of fireworks can be 

 ery, frames, produced by their own powers of recoil, there are many 

 and trans- cases where it is convenient, or even necessary, to have 

 patencies, recourse to mechanical powers ; sometimes to accelerate 

 these, and thus produce more perfect effects, and some- 

 times for the purpose of causing movements that could 

 not be made by the fireworks themselves. The fram- 

 ings and supports for fireworks also require some atten- 

 tion to render them as little cumbrous as possible, and 

 at the same time as firm as is necessary to bear the 

 shocks to which they are subjected from recoils and 

 explosions ; while it is also requisite that every thing 

 should be done in the most economical manner. 



For single rockets, vertical frames or poles are re- 

 quisite ; but we have described these more particularly 

 in our directions for firing this class of fireworks. But 

 when flights are to be discharged together, it is neces- 

 sary to have a different apparatus. This is usually 

 constructed of successive shelves in which they are 

 placed in alternate order, so that the sticks may stand 

 clear of each other; the whole forming a pyramid. 

 A cheaper and more convenient apparatus, however, 

 for this purpose is formed by making two wide shelves, 

 each perforated with holes, exactly corresponding to 

 each other, sufficient to admit the sticks, and to support 

 the mouth of the rockets. These should be separated 

 to a distance pf about two feet from each other, and 

 framed in that position by uprights at the angles, pro- 

 longed to the ground ; in which they are fastened 

 firmly, so as to form a kind of double perforated table. 

 The matches from the whole being collected together 

 they are easily fired ; and their flight is directed by 

 the guide which the position of the two holes for each 

 presents. 



The frames to carry wheels are conveniently made 

 of ash hoops, connected by spokes inserted into a nave. 

 It is also proper that the margin of the wheel, whether 

 it be a circle or a polygon, which are equally convenient, 

 should be of considerable weight. If well balanced, as 

 it ought to be, and well centred, the motion is almost 

 equally free as in a lighter wheel ; while it has the 

 advantage of acting like a fly, maintaining the impulse 

 which has been communicated to it at first. This is 

 particularly necessary to attend to ; because as the cases 

 burn out in succession, the balance becomes injured, 

 and when the weight of these is small in proportion to 

 that of the wheel, their effect in disturbing its velocity 

 VOL. Xvu. PART i. 



is less felt. The centres should be at leait two inches 

 deep where they receive the axit, to prevent any irre- 

 gular motion ; made of polished metal, well greased, 

 and with a true axis. The axit may be either fixed into 

 the supporting post by meant of a screw ; or, what is 

 better, may be kept there ready, and the wheel put on 

 it, and screwed by a linch pin or a nut. For the smaller 

 classes of single cased or spiral wheels, a sufficient centre 

 may be obtained through driven clay or wood, pro- 

 vided it be well greased, and the pins that are to terve 

 for axes are best made of brass or iron, in the form of 

 a thumb screw, with a flat cutting thread, so that they 

 may be easily fixed in the wood and withdrawn to be 

 preserved when no longer of use. These general rules 

 will direct the artist for the management of all the va- 

 rieties of wheel movements where their own force is 

 trusted to for the motions. 



Hut where wheels are of very large diameters, or the 

 circle of fire is meant to be wide, or when from the 

 cases being c'isposed in an oblique manner, the velocity 

 is so much diminished that the effect arising from their 

 revolution is injured, it becomes necessary to call in 

 the aid of the mechanical powers, and to apply revolv- 

 ing forces to them. This also is necessary in the use of 

 illuminated revolving cones or globes, or in the coun- 

 termovements of suns and other complicated figures, 

 as well as in all those works where it is necessary to 

 give motion to transparent paintings. The means of 

 doing all this, which may be varied in an infinitude of 

 ways, both as it relates to the direction and the velo- 

 city, cannot be too simple ; and it is also proper that 

 they should be concealed from the spectators, who are 

 apt to undervalue a firework that does not seem en- 

 dowed with the property of self-motion. It is, how- 

 ever, unnecessary to describe matters so simple as a 

 toothed wheel and pinion or screw, which, disposed 

 in various ways, may be made to produce any effects, 

 whether as to direction or velocity. By using the 

 pinion at 45, the horizontal and vertical directions may 

 be combined, or the one substituted for the other. If 

 the work is of such a nature, as happens in architec- 

 tural fireworks, as to conceal the operator, this machin- 

 ery may be turned by hand ; if otherwise, a weight 

 running over a pulley is easily applied to a wheel or 

 crank for that purpose. 



It would be as endless as it is unnecessary to describe 

 the various forms of frames that may be required ; as 

 they must differ with the objects of the fireworks ; and 

 we need not, therefore, attempt to direct what an artist 

 can be at no loss in accomplishing. But wherever 

 cases are to be fixed, whatever their natures may be, 

 proper sockets of metal should be provided for receiv- 

 ing them, or pins and hooks to which they may be 

 fastened. The artist must, however, take care that no 

 bounce or cracker be allowed to explode within a me- 

 tal socket, on account of the risk of injury to the spec- 

 tators. It must also be recollected, that whatever means 

 are used for fixing these, although it should even be 

 the lights for figured illuminations, they must be firm ; 

 as the explosions of the leaders and primings might 

 otherwise displace them, and ruin the effect of the work. 

 Larger cases for gerbes, Roman candles, and other fire- 

 woycs, that exert much strength, are best secured by 

 having a metal ring with two ears, or flaunches, which 

 may be nailed down to the stands in which they are 

 to be fired. 



Transparencies form a very essential part of all fire- 

 works on the great scale, as they are very ornamental. 



2G 



