DR. H. DEBUS OiST THE CHEMICAL THEORY OF GUNPOWDER. 539 
chloride, gave a precipitate of baric sulphate weighing 0*158 grm. The whole filtrate 
therefore contains 0*749 grm. of potassic sulphate. 
91 cub. centims. of the filtrate, acidulated with hydric chloride and evaporated to 
dryness, gave, after treatment of the residue with hydric sulphate, 0*395 grm. potassic 
sulphate. From this number it follows that the entire filtrate contained 1*124 grms. 
of potassium. 
91 cub. centims. of the filtrate gave, with manganous sulphate, a precipitate, which 
generated with dilute hydric sulphate 0*042 grm. of carbonic acid. 578 cub. centims. 
of the filtrate contain 0*266 grm. carbonic acid, corresponding to 0*834 grm. 
potassic carbonate. 
From the solution of the precipitate caused by manganous sulphate, 0*094 grm. of 
Miio0. 1( was obtained, corresponding to 0*597 grm. for the entire filtrate; 0*461 grm. 
of this is derived from manganous carbonate, the remainder, 0*136 grm. of MngO^, 
from the manganous hydrate precipitated by potassic hydrate. 0*136 grm. of Mn 3 0 4 
corresponds to 0*139 grm. of potassium or 0*310 grm. of K 2 S 3 . The black cupric oxide 
and sulphide was dissolved in concentrated hydric nitrate and the solution precipitated 
by baric chloride; the weight of the baric sulphate was found to be 2*754 grms. 
The following table contains the results of these experiments :— 
Composition of 
Found by 
the original solution. 
analysis. 
Potassic carbonate . 
0*829 
0*834 
,, sulphate.... 
0*597 
0*749 
„ tersulphide . 
0*887 
0*310 
,, hyposulphite . 
0*000 
0*362 
Potassium. 
1*124 
1*124 
Sulphur in CuO .... 
0*000 
0*378 
„ in K 3 S 3 0 3 . 
0*000 
0*122 
A considerable error attaches to the determination of the sulphur. The cupric oxide 
had been ignited in a Hessian crucible. From this, it appears, it became contaminated 
with silica and alumina. The baric sulphate, precipitated from the solution of the 
cupric oxide in hydric nitrate by baric chloride, contained a copper compound which I 
regard as a silicate, since it could not be got rid of even after long continued boiling 
with hydric chloride. 
The analysis gives quite a wrong idea of the composition of the original solution. 
Not only is a portion of the potassic tersulphide converted into hyposulphite, it even 
appears that some has been oxidised into sulphate. 
The following experiments prove the absence of sulphates in the reagents used for 
the above determinations. 
15 cub. centims. of the solution of potassic tersulphide, acidulated with hydric 
