= 
t24 Dr. Cuibush on the Chinese Fire, &e. 
treated with dilute muriatic acid, a quantity of black inse- 
luble matter, consisting of carbon, iron, and silicium. 
In all pyrotechnical compositions, therefore, into which 
iron enters as a component part, attention must be paid to 
these facts, in order to form a just estimate and conclusion 
of the effects they produce. In such compositions, the iron 
is first ignited by the heat generated in the combustion of 
the gun powder, of the nitrate of potash, charcoal, and sul- 
phur, and in this state is thrown out and undergoes a com- 
e combustion of the iron ing 
more than its okigMamenns 3 according to the rapidity of 
which, the flame is also rendered more or less brilliant.— 
This fact is obaibein but the character of the fire depends 
on the kind of iron employed, and hence the Chinese fire 
differs considerably from the ordinary brilliant fires. The 
oxidizement of the metal is never at the maximum, for 
when iron or steel is burnt in oxygen gas we obtain only 
the black protoxide, which consists of 28 iron + 8 oxygen 
= 36, or 100 iron + 28.68=128. os 
There: is.another.fact:to--be- obser d, namely, that al-- 
though the iron is ignited by the serra of the com 
as for instance in a rocket case, the combustion of 
the iron itself does not take place within the tube, or only 
in part, but receives for the support of its combustion the 
oxygen of the atmosphere; for the greatest brilliancy of the 
fire is actually in the air, where the ignited and minutely 
divided iron is acted upon by the oxygen gas of the atmos- 
here. 
4 As the substances which compose cast iron are chiefly 
, carbon, and oxygen, we may conclude, that as carbon 
by combustion in oxygen gas, or in atmospheric air, w 
contains it, is converted into carbonic acid, the carbon of 
the crude iron, during its combustion, forms carbonic acid. 
The products then are oxide of iron, and carbonic acid. 
These products are produced independently of those that 
result from the nitre, charcoal, and sulphur, or gunpowder, 
or other substancas employed. | 
That the heat produced, as well by the combustion of 
gun powder, as by that of the charcoal and sulphur in con- 
tact with the nitre, ignites the iron, and the iron, as we re- 
marked, is thrown off in this state, and. minutely divided. 
are facts which must strike the eye of the observer. 
