592 
DR. H. DEBUS ON THE CHEMICAL THEORY OE GUNPOWDER. 
This excess of carbon and sulphur is left free at the end of the first stage of the 
combustion. 
The free carbon now acts according to equation: 
4K 2 S0 4 +7C=2K 3 C0 3 +2K 2 S 2 +5C0 2 .(VI.) 
the free sulphur upon the potassic carbonate as follows : 
4K 2 CO s +7S=K 2 SO,+ 3K 2 S 2 +4C0 2 .(V.) 
and both united form the second stage of the combustion. These reactions are endo¬ 
thermic ; heat is not evolved but consumed ; they are not of an explosive nature, and in 
practice are probably seldom complete. 
The reactions of this second stage increase the volume of the gas formed during the 
first stage of the combustion and diminish the temperature of the products. A portion 
of the carbonic oxide is formed during the second stage by the action of free carbon or 
potassic disulphide upon carbonic acid. 
10 . The reactions represented by equations (III.), (IV.), (V.), and (VI.) can be 
expressed by one equation. If x, y, and % are positive numbers, and a indicates how 
many molecules of carbonic oxide are formed by the combustion of a weight of powder, 
containing x molecules of saltpetre, y atoms of carbon, and z atoms of sulphur, the 
following will be the general equation representing the complete chemical meta¬ 
morphosis of powder. 
afKNOo 
4-2/C 
+zS 
V. 
Y§[4a?T —162 4«](K 2 C0 3 ) 
2 L g[ 20 x— 16y+ 4,+8«](K 2 S0 4 ) 
+~h [ — 1 Ox + 8 y+1 2z — 4a](K 2 S 2 ) 
+Ts[ — 4a? d- 2 Oy + 162 24 a](C0 2 ) 
-f- aCO 
+i^x 2 
II. If a 3 = 16 , and a— 0 , the volume of the gas, (V.), generated by complete com¬ 
bustion is nearly 
_160 + 20 y + 16s ^ 
14 
and the units of heat, W, 
= 1000[1827T54 — 16‘925y— 8 T 882 :].(X.) 
y signifies in these equations the number of carbon and z that of the sulphur atoms in 
a weight of powder containing 16 mols. of saltpetre. 
The volume of gas becomes greater and the heat of combustion diminishes with an 
increase of v and z, and vice versd. 
