PYROTECHNY. 



221 



Of the in- 

 gradients 

 used in 

 pyrotech- 

 nic com- 

 position. 



1'yrotech. confirms our notion that these ancient projectiles coin- 

 "X- bined the nature of a shell and a rocket to^ctlu r. 



^ '"v""' The claims of Roger Bacon to the im rut ion of pun- 

 powder, or of any nitrous explosive compounds, how- 

 ever often repeated, are nothing, as may indeed be 

 proved from his own narration ; and as he wrote in 

 1 JT<), or eighty years before Schwartz, the German 

 monk's ill-acquired reputation may be stripped from 

 nun without hesitation. The passage in Bacon is as 

 follows: Ex hoc ludicro puerili quod fit in multis 

 mundi partibus, scilicet, ut instrumento facto ad quan- 

 titatem pollicis humani, ex violentia salis qui salpetnc 

 vocatur, tam horribilis sonus nascitur." Again, " In 

 ruptura tain modicae rei, scilicet, modici pergamcni, 

 quod fortis tonitrum excedere rugitum et corrusca- 

 tionem maximam sui luminis jubar excedit." It is 

 very plain here that Bacon is describing a cracker or 

 squib used by boys, and common in many parts of the 

 world. But we need trace the history of this art no 

 farther. Time, in complicating the movements, in 

 adding new combinations, and in discovering ingre- 

 dients, before unknown, suppliable to the production 

 of particular effects, has now rendered it an extensive 

 art, which it will nevertheless not be difficult to arrange 

 under a few simple principles. 



Of the Ingredients used in Pyrotechnic composition. 



These may be divided into the essential, or those by 

 which the fire is produced, and the incidental, by which 

 it is modified. The first of these include nitre, sul- 

 phur, charcoal, and certain resinous and oily substances ; 

 among the latter, the metals are the chief. We shall 

 examine them in order, with such remarks on their 

 varieties or preparation as are necessary. For want of 

 such discrimination, there is often much difficulty in 

 understanding the popular receipts, while failures are 

 also not unfrequent. 



Nitre. NITRE. This substance, the soul of all pyrotechny, 



is often described under two names, viz. saltpetre and 

 sal prunella. This latter is merely fused nitre; and 

 as that salt contains no water of crystallization, there 

 is no difference whatever between it and saltpetre 

 which has been carefully dried. There is, however, 

 an objection to its use, which must be pointed out. In 

 a high heat, nitre is decomposed with the loss of its 

 acid. If, therefore, in the fusion of the sal prunella 

 the heat should accidentally have been raised too high, 

 the consequence is the presence of a portion of the 

 alkali, which, by afterwards absorbing water, renders 

 the compositions into which it enters liable to become 

 damp, and thus to lose their good qualities. To pre- 

 vent this consequence, so particularly destructive to all 

 the compositions into which iron enters, the saltpetre 

 should not only be thoroughly dried, but carefully pu- 

 rified* that it may be freed from the nitrates and mu- 

 riates of lime, in particular ; salts which attract much 

 moisture. This is to be done only by careful and re- 

 peated crystallization ; nor should any nitre be ujed 

 which has not previously been tested with a solution of 

 subcarbonate of potash, and with that of nitrate of mer- 

 cury. To stand these without having any marks of 

 precipitation, is a proof of that absolute purity which 

 is most essential. 



ilphur. SULPHUR. There are very few compositions in which 

 this is not required. In its usual marketable state, it 

 is always sufficiently pure, and requires no examina- 

 tion ; that is to say, when solid or in rolls. Pyrotech- 

 nists must be told that there is no difference between 

 cast sulphur and flowers of sulphur ; but as this latter 



is sometimes used from its being already powdered, Fjrrouch. 



it is proper they should know that it almost ml way* "y- 

 contains a considerable proportion of sulphuric acid or """V" 

 oil of vitriol. If it is to be used, therefore, it should 

 always be carefully washed ; as this ingredient is not 

 only injurious, from its moisture and property of ab- 

 sorbing water, but from its destroying the iron in those 

 compounds into which this highly ornamental ingre- 

 dient enters. The perishable nature of all the iron 

 fires must be attributed chiefly to this and the preced- 

 ing species of neglect. 



CHARCOAL. In many fireworks this is an indispen- Cl.ircoti. 

 sible substance ; in all cases indeed where iron is used, 

 and where fires are required to be strong, or of a red 

 colour. But it is subject to many variations of quality, 

 not known to pyrotechnists, and which we shall there- 

 fore explain. It will be seen that an attention to these 

 is of considerable importance ; but we consider it of 

 no moment how the charcoal is burnt, whether in pits 

 or cylinders, provided it be completely deprived of all 

 its volatile par -3. All coals that contain much subcar- 

 bonate of potash, are objectionable, for the very same 

 reasons above assigned ; namely, their property of ab- 

 sorbing water. They are easily examined by washing 

 the powder in hot distilled water, and testing the solu- 

 tion with muriate of lime. That of litmus or turmeric 

 is too delicate ; as these will show proportions of alkali 

 that can be productive of no evil consequences. It 

 must next be recollected, that charcoal is required for 

 two distinct purposes, force and ornament. For these 

 two objects, different kinds are required. The greatest 

 force is procured by the coals of soft wood, such as 

 willow and alder ; and still more by that of the Rham- 

 nus frangula, or black dogwood. These, therefore, 

 should always be used for sky rockets ; in which forct 

 is essential, as conducing to high flights ; and as far as 

 a rocket composition includes mealed powder, such 

 charcoal will be an ingredient. Those who are desirous 

 of perfection, will use the same woods for the added 

 charcoal. Where the object, on the contrary, is to ob- 

 tain common red fire, or burning sparks, the charcoal 

 of hard woods is preferable. Still belter is it, when, 

 by being long ignited in close vessels, it requires an, 

 extreme degree of hardness ; as it not only burns 

 brighter, but is thrown out in larger sparks, from its 

 greater power of resisting the force with which the 

 compositions are driven. For the same reason, char- 

 coal for these purposes ought to be coarsely powdered, 

 and the larger parts separated for use ; whereas in the 

 case of compounds, where strength alone is wanted, * 



it cannot be too fine. As far as sky rockets are wanted 

 for purposes purely ornamental, they thus require 

 coarse charcoal. Lastly, there are some varieties of 

 charcoal which have the property of producing com- 

 pound sparks, not unlike those generated by iron ; or 

 the original spark bursts after the first explosion, so as 

 to throw out stars of light. The bark of the oak fur- 

 nishes this kind of coal ; which may also be procured 

 from mahogany and other hard woods of hot climates. 



BITUMEN, ROSIN, TALLOW, PITCH, COAL. The for- Bitumen, 

 mer four are used only in military fireworks, and re- Ron> Ac- 

 quire no particular notice. Coal is recommended in 

 many of the receipts for ornamental works, as produc- 

 ing dark, and even black flames. It is always either 

 useless or pernicious. The flame which it gives, if 

 thoroughly burnt by using nitre enough, is white ; 

 and if this is in an under proportion, it yields nothing 

 but smoke, and is even apt to be extinguished. 



CAMPHOR. This is recommended to make a white Camphor. 

 3 



