Dr. Cutbush on the Chinese Fire, &. 125 
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- 
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, required 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. 
ur 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 cylindersyare filled in 
the usual manner. These cases are several thicknesses of 
paper, and when filled are primed with meal powder and 
quick match. i 
n 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 Taths 
of an inch in diameter, No. 1; ;7;ths to +$ths, No. 25 and 
No. 2 is ad. 
In charging with the composition, care must be taken to 
