CHINESE AND BRILLIANT FIRE. 



the extreme rapidity with which the clastic fluid issues through the 

 neck of the rocket to throw itself downwards, and therefore the 

 rocket ascends by the excess of the one of these forces over the 

 other. 



This howevrr would not be the case, unless the rocket were 

 pierced to a certain depth. A sufficient quantity of elastic lluid 

 would not be produced ; for the composition would inflame only in 

 circular coats of a diameter equal to that of the rocket j and expe- 

 rience shews that this is not sufficient. Recourse then is had to 

 the very ingenious idea of piercing the rocket with a conical hole, 

 which makes the composition burn in conical strata, which have 

 much greater surface, and therefore produce a much greater quan. 

 tity of inflamed matter and fluid. This expedient was certainly 

 sot the work of a moment. 



CHAP. IV. 



BRILLIANT FIRE AND CHINESE FIRE. 



/\S iron filings, when thrown into the fire, inflame and emit a 

 strong light, this property, discovered no doubt by chance, gave 

 rise to the idea of rendering the fire of rockets much more brilliant, 

 than when gunpowder, or the substances of which it is composed, 

 are alone employed. Nothing is necessary but to take iron filings, 

 very clean and free from rust, and to mix them with the composi. 

 tion of the rocket. It must however be observed, that rockets of 

 this kind will not keep longer than a week ; because the moisture 

 contracted by the saltpetre rusts the iron-filings, and destroys the 

 effect they are intended to produce. 



But the Chinese have long been in possession of a method of ren- 

 dering this fire much more brilliant and variegated in its colours ; 

 and we are indebted to father d'lncarville, a Jesuit, for having made 

 it known. It consists in the use of a very simple ingredient ; 

 namely, cast iron reduced to a powder more or less fine ; the 

 Chinese gave it a name, which i.s equivalent to that of iron sand. 



To prepare this sand, take an old iron pot, and having broken it 

 to pieces on an anvil; pulverise the fragments till the grain* are not 



