536 
DR. H. DEBUS ON THE CHEMICAL THEORY OE GUNPOWDER, 
The mean of these experiments is 24 - 26 cub. centims. of iodine solution for 
25 cub. centims. of the filtrate, hence, 100 cub. centims. of the united filtrate and 
wash water contain 1‘844 grms. of potassic hyposulphite. 
II. 100 cub. centims. of the same filtrate evaporated with pure hydric sulphate 
gave 3*653 grms. of potassic sulphate, which dissolved in water to a clear and neutral 
liquid. A similar quantity of hydric sulphate to that which had been used in this 
experiment, and out of the same bottle, left no residue after evaporation. 3*653 grms. 
of K 3 S0 4 contain 1*6375 grms. of potassium, 1*844 grms. of K 2 S 3 0 3 contain 0*757 grm. of 
potassium; therefore, more than one-third, nearly one-half, of the potassium of the 
K 3 S 4 . (;7 in the original solution appears after treatment with cupric oxide as potassic 
hyposulphite. 
The presence of potassic hyposulphite is assumed on account of the behaviour of 
the liquid with iodine solution. A direct proof of its presence appeared to be desirable. 
Reactions of the filtrate of the cupric oxide. 
a. Hydric chloride caused turbidity after some time, probably from sulphur. 
b. Barium chloride, a white precipitate, only partly soluble in hydric chloride. 
c. Cupric sulphate gave after neutralisation with acetic acid a blue precipitate, 
which turned dark brown at 70-80° C. 
A mixture of .sodic hyposulphite, potassic acetate and cupric sulphate behaved in a 
similar manner. 
cl. Lead acetate and silver nitrate, respectively, gave the same reactions as they do 
with a solution of sodic hyposulphite. 
122 cub. centims. of the strongly alkaline filtrate were neutralised with acetic acid 
and allowed to evaporate over hydric sulphate under the receiver of an air-pump. 
After a few days a great number of prismatic crystals were observed. These crystals 
warmed with alcohol fused into an oily liquid, which recrystallised on cooling and did 
not dissolve in alcohol. 
Alcohol added to the mother liquor of the crystals produced a crystalline precipitate. 
The original crystals, and the crystalline precipitate united weighed 2*634 grms. 
According to the determination with iodine solution 122 cub. centims. of the filtrate 
from the cupric oxide, contain 2*249 grms. anhydrous, or 2*604 grms. hydrated salt of 
the formula 3K 2 S 3 O s , 5H 3 0. The crystals dissolved easily in 3 cub. centims. of water 
with absorption of heat; from this solution 2*457 grms. of salt were reobtained. 
0*497 grm. of the same, dissolved in water and mixed with a solution of strontium 
chloride, gave, after two days’ standing, a very small precipitate. 
0*903 grm. of the salt, dissolved in 50 cub. centims. of water, gave, on addition of 
1 grm. of barium chloride a white precipitate, which left, after treatment with 
boiling water, 0*017 grm. of barium sulphate. The filtrates of the barium sulphate 
yielded a fine crop of barium hyposulphite. 
