PYROTECHNY. 



ccssful, a spiral line of fire. This case may he tied on 

 the stick instead of being fastened on the rocket itself, 

 ""~ Y "~" 1 ' the stirk for that purpose being made so us to pass be- 

 yond the rockrt la-ad ; but this method i-, It-ss likely to 

 succeed, as interfering more with the flight. It has 

 been attempted to produce the same effect in a more- 

 perfect manner by perforating the transverse case in 

 the middle, and fastening it upon a spindle fixed in 

 the top of the rocket. But this is too complicated ; 

 and, upon all these contrivances we may remark, that 

 although theoretically practicable, and sometimes suc- 

 cessful on trial, they are apt to fail in the fundamental 

 object, by interfering with the ascent of the rocket it- . 

 self. The operator must recollect that a rocket, in it* 

 simplest state, and when least encumbered, is a very 

 delicate and ticklish machine, and that it will not ea- 

 sily bear to be tampered with. In all these contrivan- 

 ces, it is necessary to have a longer stick and a more 

 distant point of equilibrium than in simple rockets. 



A tourbillon may also be combined with a rocket in 

 the act of ascending, but, on account of the weight to 

 be carried, the rocket must have great power. Thus, 

 a two pound rocket will not easily be induced to carry 

 more than an eight ounce tourbillon. In making this 

 attempt the tourbillon must be made complete, as when 

 it is to be fired alone ; that its own force of ascent may 

 assist that of the rocket. But it need not be so com- 

 pletely bored ; we must, however, be more particular. 

 The transverse case being driven and c'osed at both 

 ends as before, with the same composition as the rocket, 

 the two horizontal and opposed holes at the extremi- 

 ties are to be bored and prolonged obliquely into the 

 case for about a diameter and a half in length, that the 

 force of the issuing fire may be sufficient to produce a 

 circular recoil. Thus, the tourbillon becomes a wheel 

 revolving round the line of flight of the rocket. When 

 it is fixed on the rocket head, two holes must also be 

 bored, simply into the case, one on each side of it, and 

 directed downwards, so that each will produce a stream 

 of fire to assist in the rocket's ascent. Care must be 

 taken to secure the leaders from each of those four 

 holes in such a manner that they may all take fire as 

 soon as the rocket is ready to quit the support, which 

 is easily managed by bringing that which unites the 

 whole, down to the mouth of the rocket, and by put- 

 ting about a quarter of an inch of a slow composition 

 into its mouth, so as just to retard for a couple of se- 

 conds the communication between the mouth of the 

 rocket and the quick-match of the leader. No hole is 

 required at the top of the rocket in this case, but it 

 must be covered as usual, with a cone, to diminish the 

 resistance of the air. Now, as it is essential in this 

 contrivance, that the rocket should be so balanced as 

 to turn round its own axis in ascending, it is requisite 

 that the stick should be round instead of square, and 

 that instead of being attached to the side, as usual, it 

 should be prolonged from the axis. This is managed 

 by fastening it to two metallic stays of light tinned 

 iron, embracing the opposite sides of the case, so that 

 the stick may not commence till the place where the 

 point of equilibrium is situated, which ought also to be 

 a full rocket length from the vent. This stick ought 

 also to be of unusual length itself. We may add, that 

 the effect of this compound rocket is extremely strik- 

 ing, but that it requires the greatest nicety in the exe- 

 cution and in the firing. 



The fire of a rocket may be varied in a pleasing 

 manner by dispersing it during the ascent, so as to pro- 

 duce a wide or divided shower instead of a simple train 



of sparku. To produce thin effect, a plate of tinned 

 iron, of about the size and figure of a half-crown, must 

 be fastened on the stick about two inches below the 

 vent, so as to meet the stream of fire aa it issue*. The 

 method of doing this is too simple to require any de- 

 tail, and the effect of it is easily understood. 



It is possible to attach two or even three rockets to 

 one stick, so as to produce a* many ascending streams 

 of fire, and this project is recommended in the books* 

 of pyrotechny. In this case a much larger stick it of 

 course required. But we cannot recommend this con* 

 trivance. It is very difficult to make it succeed in the 

 firing, and the effect, when it is attained, is so little 

 better than that of a rocket of larger size, as not to be 

 worth the risk of failure. A similar attempt, with a 

 slight variation, has been made to fire many rockets in 

 one mass. These are known by the name of chained 

 rockets. To do this, six or more rockets are fastened 

 parallel to each other by means of packthread or other- 

 wise, each hav'ng its separate stick ; and the whole are 

 fired by one leader. It has also been attempted to 

 connect them loosely together, so that they may be in 

 a certain degree independent of each other. This also 

 is done by means of packthread. But in all these 

 schemes we must remark, that the chances of failure 

 are so great, that they are not worth trying, particular- 

 ly as the effect, should it succeed, is not very good. 

 Where they are strung loosely together, in the manner 

 last mentioned, they are particularly subject to become 

 entangled and go wrong. 



Simple rockets may be used with reports only in- 

 stead of ornaments, and their effect is good, while they 

 serve to excite the attention of the spectators where 

 that is necessary, preparatory to some general display. 

 In making this kind, after the clay has been driven on 

 the top of the composition and the priming hole bored, 

 a diameter and a half of the bore must be filled with 

 powder above it. The case must then be secured above 

 this bouncing charge with a wadding of tow and glue, 

 as it would destroy the explosive property of the pow- 

 der were it to be hard driven with clay, and as it is 

 impossible to choke the case above it. A cone is then 

 added for the usual reason of diminishing the resist- 

 ance of the air. 



There are two methods of carrying a single light 

 by means of a rocket, instead of using the common or- 

 nament of stars, which are quite practicable, and have 

 a very good effect, although not mentioned in the books 

 of pyrotechny. For both, two diameters of the csse 

 must be left empty above the clay. This is to be filled 

 with the same antimonial composition which is used 

 for signal lights, or with that from zinc, both of which 

 will be found mentioned in their proper places, accord* 

 ing as it is wished that the light should be white or 

 blue. It must also be rammed in pretty firm, so that it 

 may not fall out when the rocket oversets to descend. 

 This light may be caused to descend after the rocket 

 is burnt out, in which case the effect of it is very agree- 

 ably prolonged ; but care must be taken that it may 

 not alight on the ground where it could do any harm, 

 as the white light produces a very strong fire. If this 

 practice is to be adopted, a hole must as usual be bored 

 through the clay on the top of the rocket charge, and 

 also through the wbite light, that it may take fire at the 

 surface : this hole is to be filled with mealed powder. 

 But if the rocket is to carry the light upwards in as- 

 cending, such a hole is unnecessary. Instead of it, a 

 leader must be conducted from the mouth of the roc- 

 ket to the head, which, in this case, will not require a 



