246 



PYROTECHNY. 



Pyrotech- 

 ny. 



that it may be strong when it arrives at the middle, so 

 _ , as to end in a lively manner. The remainder of the 

 case is then to be filled with the same compositions in 

 a reverse order. The case being then completely 

 closed at both ends, as for the tourbillon, two holes 

 must be bored into it at the extremities, and on oppo- 

 site sides, that it may revolve like a wheel. To in- 

 sure a sufficient velocity, if that is desired, each of 

 these bores may also be prolonged according to the 

 axis of the case, as in a rocket, but they need not ex- 

 tend inwards above a diameter. It must be primed 

 by a single leader, that both ends may fire at once. 



To arrange it for firing, it must be fixed on a 

 * ' 9- short obtuse cone a, like a child's top, taking care that it 

 be perfectly balanced, and that it may be spun like a 

 top on the table where it is to be fired. When that is 

 done it acts the part of a wheel on the table, with 

 some little variety, arising from its lateral change of 

 place. From the proximity of the spectators to such 

 a firework as this, it will not well admit of terminat- 

 ing with a bounce. But it may end with a discharge 

 of serpents. This is done by fixing a short thick case 

 in the centre, with the opening directed upwards, 

 which may be filled with serpents, and the requisite 

 priming communicating by means of a hole with 

 the middle of the firework. This case must not ex- 

 ceed an inch in length, lest it should overbalance the 

 wheel ; and the serpents, that must not be more than 

 an inch and a half long, may be attached and retained 

 in their place by a bit of thin paper pasted round 

 them and the case together. These fireworks may 

 also be made double, by fixing two rockets transverse- 

 ly on the cone, all the vents being directed the same 

 way ; and in this manner they succeed better, as the 

 balance is more perfectly preserved. 



Of Roman Candles. 



Of Roman These are also known by the name of fire-pumps. 



candles. They are very much used on all occasions of public 

 display, as they are exceedingly ornamental ; as well 

 as on the most common occasions, by the people, and 

 by school-boys. Though apparently simple, they are 

 by no means easy to make so as to act well, and re- 

 quire therefore considerable attention, and very par- 

 ticular directions. 



It is requisite that the cases should be exceedingly 

 strong, as they have to bear considerable force without 

 at the same time running any hazard of bursting. 

 All the paper, therefore, which enters into the case, 

 should be pasted at every turn, and well rolled, that 

 it may be as hard as a board, and as strong as a 

 piece of ordnance, which it is, in fact, as far as its 

 use is concerned. Those who have frequent occasion 

 to use this firework, for public purposes that recur 

 often, will find it good economy to have iron cases as 

 strong as gun barrels, which, of course, must be care- 

 fully cleaned and greased when out of use. The 

 length of the case should not be less than twelve 

 diameters ; and as this firework, from its nature, can- 

 not be very durable, it may even range as far as fif- 

 teen, if carefully made, beyond which the length be- 

 comes inconvenient, as the sparks have too far to tra- 

 vel through it before they make their appearance. 



Before beginning to fill it, it is necessary that all 

 the compositions which are to be introduced into it 

 should be ready arranged under the operator's hand, 

 as it is necessary to keep an accurate account of their 



succession and proportions. Four kinds of fire are Pyrotech- 

 all that can be introduced, but three at least are neces- ny. 

 sary. These are the common sparkling fire from SP V" 

 charcoal; that from iron; the blue antimonial light; and 

 the white light, the receipts for which may be selected 

 at the operator's pleasure, from the table of composi- 

 tions, with this recollection, that the sparkling fires 

 need not be of a very strong kind, as there is no recoil 

 wanted, and nothing but a stream of sparks. The 

 stars for this purpose may also be taken from the 

 compositions described for stars in general ; but blue 

 and white ones will be sufficient. It is requisite, how- 

 ever, that the stars used for Roman candles should be 

 short cylinders, moulded in a case of the same dimen- 

 sions, that they may take up as little room as possible, 

 and run the least risk of being broken in the driving 

 of the case. In point of thickness they need not ex- 

 ceed one quarter of the diameter of the charge, as it is 

 a great object to save room, and as the star ought, if 

 possible, to be burnt out before it falls to the ground. 

 Thus we will here suppose, that the case is an inch 

 in the interior diameter, when its length will be twelve 

 inches, and the length of each star a quarter. 



The case is closed at the lower extremity, and is 

 filled from above; and as much force cannot be used, 

 it may be driven without the precaution of using a 

 mould. The first thing to be introduced is powder in 

 the grain, to the amount of a diameter, on which is to 

 be placed a star, or two or three, should the artist 

 prefer it. But care must be taken that there be not 

 powder enough to burst the case, as that would spoil 

 the effect. If the artist is desirous that there should 

 be a report at the end, it is better to attach a separate 

 maroon, or a number of these, or else a folded cracker, 

 which must communicate with the end of the charge, 

 by a proper touch-hole. 



On the top of the star must now be placed the 

 amount of a diameter or more, of the brightest spark- 

 ling fire, which must be rammed down as hard as can 

 safely be done, without breaking the star. But none 

 of these compositions will bear so much driving as 

 wheels or sky-rockets, for that reason. Another 

 charge of powder, and another star, may then be intro- 

 duced, and so on alternately, at the discretion of the 

 operator ; taking care to vary the fires as the firework 

 proceeds, by means of the charcoal fires and the slow- 

 flaming compositions. But it is a general rule, that 

 the brighter and stronger fires must be at the bottom, 

 where the length of the case requires it, and that the 

 slow ones should only be introduced high up in the 

 case, as their flames would otherwise be half suffocat- 

 ed. The operator must also remember, that wherever 

 a slow composition is introduced, it need npt occupy 

 so much space as a quick one ; and he must also take 

 care that one species of composition is firmly settled 

 before another is introduced, that their effects on burn- 

 ing may be preserved distinct. With these attentions 

 he cannot fail; and we shall only yet remark, that a 

 twelve inch case may carry from six to eight or ten 

 stars. 



As this firework is transitory, its effect may be im- 

 proved and prolonged in various ways. We shall de- 

 scribe a few of these. Many Roman candles may be 

 fired together in a vertical direction ; but, to produce a 

 good effect from this method, all that are to burn at 

 once must be so far different in the proportional distan- 

 ces of the stars in their composition, that there may 

 always be a star or two in the air ; a matter easily ac- 



