244 



PYKOTECHNY. 



Pjrrotecb- are fired, the line should cross the direction of the spec- 

 ^^ tator's sight. If the rocket is to carry a wheel, as 



hereafter to be described, the effect is better if it lies in 

 the direction of the line of vision. 



To carry the rocket on the line, there must be a 

 perforated piece of wood, or a paper tube of the same 

 length, adapted to it, through which the line is to pass 

 freely, and it will also insure the facility of flight if the 

 line is soaped or greased. The priming and firing of 

 such a rocket is so simple an affair, as to require no 

 particular directions ; and it is easy to understand what 

 its effect must be. But as a single line rocket is soon 

 expended, and as it is very easy to compound them, 

 since there is no difficulty in procuring sufficient force, 

 it is better that they should be constructed in this man- 

 ner. Two rockets may be applied to the same tube, 

 but in reverse order, so that the mouth of the one and 

 the termination of the other are approximated. A leader 

 is then conducted from the end of the first to the be- 

 ginning of the second, so that when the rocket has ar- 

 rived at the end of its flight it returns again in a simi- 

 lar manner. Pursuing the same principle, four may be 

 used instead of two, or even more, so as to keep up a 

 succession of alternations ; nor is there any other limit 

 to this but the strength and horizontality of the line, 

 because the friction is so small on the horizontal plane, 

 if the arrangements are well made, that a good rocket 

 will carry forwards a great many others. 



But the variety of effects which line rockets are able 

 to produce, are not limited to mere alternations. It is 

 easy, for example, to attach to it a bright light of 

 any kind, which may burn as it goes on, and which 

 may be made sufficiently durable to last out three or 

 four alternations. Such a light should be attached in 

 a parallel manner, that it may not impede the motion, 

 and at a sufficient distance from the line to avoid all 

 hazard of burning it. It is also easy to attach a Ro- 

 man candle to it, (a firework hereafter described) by 

 which means a very pleasing effect may be produced, 

 as it will continue to discharge stars during its flight. 

 Thus, also, it may be caused to discharge serpents, by 

 attaching these to the cases in the manner already de- 

 scribed under the head of sky-rockets. 



It is much easier to attach transparencies to line 

 rockets, as is directed in the books of pyrotechny, than 

 to produce any useful effects in this way. It is easy, 

 for example, to understand how a line rocket may car- 

 ry the figure of a flying dragon, or a ship. Such 

 an object may be made of transparent cloth or .pa- 

 per, properly stretched upon a frame, and illumi- 

 nated within, or provided with lights, or fires, or 

 crackers, which may be lighted at any time the art- 

 ist thinks proper, by regulating the disposition of the 

 quick or slow match which is to fire them. But the 

 rapidity of the line rocket generally destroys the effect 

 of these contrivances ; nor is it very easy to make them 

 sufficiently slow, without a risk of their stopping alto- 

 gether should any temporary obstruction occur in the 

 line or in the rubbing parts. A dextrous and atten- 

 tive workman may, however, surmount these difficul- 

 ties ; and in that case he has it in his power to produce 

 many pleasing effects. But it is unnecessary to describe 

 particularly how these transparent figures may be 

 made and varied, as that may be equally well done 

 without directions by any ingenious workman. 



A line rocket may be varied in a very agreeable man- 

 ner by causing it to carry wheels at the side ; but in this 

 case its motion should be slow. The wheels for this 

 purpose are made of single cases, in the manner here- 



after described, and are attached by a spindle to the Pyrotech 

 wooden tube which carries the rocket. They are fired n y- 

 at the same time as the rocket ; and as one may be s *"~v~""* 

 placed on each side of it, an alternation may in this 

 way be produced. In this case the line must cross 

 the direction of the spectator's sight. 



But there is a far superior way of combining the 

 wheel with the line rocket ; only that it requires much 

 management, as it is attended with considerable diffi- 

 culty. In this case the line must run in the direction 

 of the line of vision, as the intended effect is only to 

 be attained in this manner. The intention is to cause 

 the wheel to revolve round the line while it moves 

 horizontally, and the effect is extremely brilliant. In 

 this case it is better that there should be four or six 

 alternations ; as the length of the wheel is easily made 

 to coincide with that number. 



The rockets for this purpose must be disposed round 

 a central tube, well fitted to the line, and very free to 

 move. The tube carries, by means of spokes fixed in 

 it, a wooden wheel of the usual construction, round 

 which the rockets forming the wheel of fire are to be 

 fixed. Thus the tube forms the centre of the wheel, 

 and the line its spindle. It is plain that if this is well 

 managed, the wheel will continue to revolve while the 

 rockets retreat, and the same will take place as it re- 

 turns. If the wheel is to be small, a single rocket at a 

 time will suffice to carry it forwards ; if large and 

 weighty, it will be preferable to fire two rockets at 

 once in the same direction, and to provide two in the 

 same manner for the return ; and these matters are, of 

 course, easily managed by a proper disposition of the 

 leaders. In constructing this compound firework, the 

 two parts, or the wheel and the line rockets, must be 

 timed, so that the whole' may expire together. Thus, 

 for example, an hexagonal wheel of six cases would 

 burn with six line rockets separately. If there are but 

 four of these, the wheel may be a square, as the form 

 is of no moment ; or else two cases on opposite sides 

 of it may be fired at once, which will add much to the 

 brilliancy of the effect. The same arrangement must 

 be made if two of the line cases are .arranged to burn 

 together. We need only add, that in firing this rocket 

 it is better that the wheel should ba, fired first, and 

 perhaps even suffered to burn for a considerable time 

 before the line rocket is kindled. It will thus appear 

 to the spectators as a common fixed wheel, and the 

 surprise will consequently be the greater when it is 

 seen unexpectedly to fly away. It is a good rule on 

 all occasions for pyrotechnists to recollect, that to ex- 

 cite surprise by something that was unexpected, is an 

 essential part of their business, and that their inten- 

 tions should, therefore, be concealed as much as possi- 

 ble. 



There is yet another way in which a line rocket 

 may be caused to produce somewhat of the effect of a 

 wheel, but it must be double, or two must burn toge- 

 ther. For this purpose the tube which is to receive 

 them, must be so made as to receive them in an oblique 

 position instead of a parallel one, and in such an order 

 as to form the two consecutive parts of a spiral. Thus, 

 when fired, the tendency of each to recoil will be com- 

 bined with a spiral one, so that in retreating they will 

 revolve round the line. It is evident that the balance 

 must in this case be made perfect, as the accurate per- 

 formance of the firework will depend principally on 

 this. By altering the angles which the fireworks 

 make with the axis of motion, the circle of fire may be 

 varied accordingly ; but it must be recollected, that as 



