Dr. Cutbush on the Chinese Fire, ^c. I'25 



The quantity of iron, it will be seen, which enters into 

 the composition of different preparations, is various accor- 

 ding to the purpose for which they are used. The effect 

 may be varied with the quantity of the metal. With res- 

 pect to the ignition of the metal, and consequently of the 

 combustion, these may be affected as the proportions of the 

 nitre and charcoal are increased or diminished. In prepar- 

 ing the mixtures according to formulae, attention is required 

 in selecting pure materials. The proportions should be ac- 

 curate, and the mixture intimately made, or the effect would 

 be doubtful, and otherwise uncertain. 



There are no preparations, perhaps, which require more 

 care and exactness than pyromixtures ; for their perfection 

 depends on the quantity of the materials made use of, the 

 exact proportion of each article, and the intimate mixture 

 ,of the whole. 



" There is a method, however, i-equired for preparing the 

 composition for Chinese fire in particular. The substances, 

 except the sulphur and pulverized or granulated cast iron, 

 are to be passed several times (three generally) through a 

 sieve. 



The sulphur and cast iron are mixed by themselves, and 

 afterwards with the other ingredients. They are then to 

 be turned over frequently by the hand. Cases, which are 

 usually made of paper, in the form of cylinders, are filled in 

 the usual manner. These cases are several thicknesses of 

 paper, and when filled are primed with meal powder and 

 quick match. 



In order to make the mixture of the sulphur and iron 

 more intimate, the latter may be moistened with spirit of 

 wine, which contains no water, as water would rust the 

 iron, and destroy its effect. When the cast iron is reduced 

 to powder, or rather grains, it is divided into several sorts, 

 proportioned to the calibre employed. These sorts are 

 marked and numbered as follows : for calibres under yV^s 

 of an inch in diameter. No. 1 ; yV^s to Ifths, No. '2 ; and 

 No. 3 is adapted to cahbres above. 



In charging with the composition, care must be taken to 



turn it over repeatedly at every other ladle-full ; because 



. the iron, which is the heaviest substance, is liable to fall to 



the bottom. If the composition is not equally mixed, or 



diffused, the fire would be irregular, and go out by puffs. 



