128 JDr. Clutbush on the Chinese Fire, ^c. 



Another, for gerbes often and eleven twelfths, and one inch 

 calibre. 

 Nitrate of potash - - - 1 oz; 



Sulphur _._--! do. 

 Meal powder - - - - 8 do. 

 Charcoal - - - - - 1 do. 

 Pulv. Cast iron - - - - 8 do. 



Before the present improvement took place, that of using 

 cast iron, ordinary iron filings were altogether employ- 

 ed. Iron and Steel filings we remarked, were both 

 used in the composition of brilliant fire. When iron or 

 steel dust are used, the proportion it bears to other sub- 

 stances is various, viz. to meal powder as one to five, one 

 to ten, he. In one formula the proportion is still greater, 

 and in another less ; but by mixing seven and a half ounces 

 of steel dust with meal powder, saltpetre, and sulphur, in the 

 proportion of eleven pounds, one pound two ounces, and four 

 ounces respectively, is the best calculated to produce the or- 

 dinary brilliant fire. 



With respect to what is denominated fire jets, or fire 

 spouts, we may add that they are similar. They are cases 

 charged solid with particular compositions. These jets are 

 made with a calibre of one third of an inch, to one and one 

 third of an inch in interior diameter. They are seven or 

 aight exterior diameters in length, and are charged with the 

 particular composition, driving each charge with twenty 

 blows of a small mallet. The first charge is the ordinary 

 fire composition. Fire jets are calculated for turning, as 

 well as for fixed pieces. 



Common fire for calibres of one third of an inch. 

 Meal powder - - - - 16 oz. 

 Charcoal _ _ - - 3 do. 



Common fire for calibres of five twelfths to half an inch. 

 Meal powder - - - - 16 oz. 

 Charcoal _ - . 3 do. 4 dr. 



Common fire for calibres above half an inch. 

 Meal powder - - - - 16 oz. 

 Charcoal - - - - 4 do. 



