DR. H. DEBUS ON THE CHEMICAL THEORY OF GUNPOWDER. 
537 
As this salt is, according to my experience, easily obtained in a pure form, the whole 
of the potassium hyposulphite was converted into the barium compound for the 
following analytical determinations. 
0'882 grm. baric hyposulphite boiled with hydric nitrate gave 0*763 grm. of baric 
sulphate ; the filtrate of this gave, on addition of barium chloride, another quantity of the 
same salt, which, after ignition and treatment with hydric chloride, weighed 0'753 grm. 
Therefore in 100 parts : 
Experiment. 
Theory. 
BaS 2 O g 
BaSgOg, H 3 0. 
Barium . 
. . . 50*86 
51*70 
48*41 
Sulphur . 
. . . 23*60 
24*15 
22*61 
The potassium salt from which the barium hyposulphite had been prepared gave 
the following reactions :— 
a. Hydric chloride produced, a few moments after its addition, a slightly yellow 
turbidity. 
b. Cupric sulphate gave a slight turbidity at common temperatures, on boiling, a 
copious brown precipitate. 
* 
c. Lead acetate, a white precipitate, which did not change its colour at 100° C. 
d. Ferric chloride gave the usual violet colour. 
e. Silver nitrate, a white precipitate, which turned black at higher temperatures. 
According to these experiments there can be no doubt that, by the treatment of a 
solution of a mixture of potassic penta- and tetra-sulphides with cupric oxide, large 
quantities of potassic hyposulphite are formed. 
The mother liquor of the potassic hyposulphite, from which this salt had been 
removed by means of alcohol, was left to evaporate in vacuo. The crystalline residue, 
heated in a platinum crucible, produced an oily liquid, which crystallised on cooling, 
like potassic acetate, and weighed 2’616 grms. 
It was converted by means of hydric sulphate into 2’404 grms. of potassic sulphate. 
2*616 grms. of potassic acetate should give, according to theory, 2*320 grms. of 
potassic sulphate. If we assume that, in the solution obtained by the treatment 
of potassic polysulphides with cupric oxide, only potassic hyposulphite and potassic 
hydrate are present, then, according to the numbers given on page 536, 122 cub. 
centims. of the filtrate from the cupric oxide should have given 2*697 grms. potassic 
acetate, instead of 2*616 as found by experiment. 
Hence, we may conclude that 100 cub. centims. of the filtrate from the cupric oxide 
contain : 
1*844 grms. potassic hyposulphite, 
1*263 ,, ,, hydrate, 
and a very small amount of potassic sulphate. 
3 z 2 
