540 DR. H. DEBUS ON THE CHEMICAL THEORY OF GUNPOWDER: 
chloride, boiled, filtered and precipitated witli baric chloride gave only 0‘0005 grin* 
baric sulpha,te. 80 grins, of cupric oxide were dissolved in hydric chloride and the 
solution mixed with 1 grm. of baric chloride; even after two days’ standing no 
precipitate could be observed. 
0'854 grm. potassic carbonate, examined in a similar manner, was found to contain 
only 0'0007 grm. of sulphate. 
1 grm. of sodic hyposulphite in 100 cub. centims. of water gave with barium 
chloride a crystalline precipitate which proved to be completely soluble in boiling 
water. Baric chloride, added to the water used in the experiments, and hydric 
chloride caused no precipitate. 
1 grm. of sodium hyposulphite was dissolved in 200 cub. centims. of water, hydric 
chloride added, and the solution boiled during three-quarters of an hour. 
Baric chloride precipitated 0'022 grm. of baric sulphate. Another similar 
experiment yielded 0'028 grm. baric sulphate. 
From these experiments it is clear that in a solution containing hyposulphites and 
sulphates, the latter cannot accurately be determined by the ordinary method. The 
error from this source is, however, not sufficiently great to account for the discrepancy 
between the sulphate taken and found in the experiment described on page 539, and 
exhibited in the table given on that page. 
Accordingly, it appears probable that by the action of cupric oxide upon potassic 
tersulphide, in presence of potassic carbonate , not only potassic hyposulphite but also 
potassic sulphate is formed. 
15 cub. centims. of a solution of potassic sulphide were acidulated by addition of 
hydric chloride, and by boiling and filtration were separated from the precipitated 
sulphur. The potassic chloride left, after evaporation of the filtrate from the sulphur, 
was converted, by means of hydric sulphate, into, potassic sulphate. The weight of 
this salt was found to be 2*554 grms. 
5 cub. centims. of potassic sulphide solution, mixed with potassic hydrate and oxy- 
dised by chlorine, yielded 3*58 grms. of baric sulphate. 10 cub. centims. of potassic 
sulphide solution, precipitated by zinc sulphate, and the filtrate from the zinc sulphide 
examined by means of iodine solution for hyposulphites, gave numbers which indicated 
in 15 cub. centims. of the sulphide solution 0*114 grm. of potassic hyposulphite. 
Sulphuric acid was not found in the sulphide solution. 
15 cub. centims. of potassic sulphide solution, out of the same bottle from which 
the quantities used in the above experiments had been taken, were mixed with 
solutions of 1*188 grms. of potassic sulphate, and of 1*650 grms. of potassic 
carbonate. 
The mixture so prepared had the following composition :— 
