' CHEMISTRY OF FUMIGATION. 95 
Experiments to determine the best proportion of chemicals to be used. 
Amount of chemicals used. 
HCN re- 
maining in 
residue 
(per cent 
of total). 
HCN ex- 
pelled (by 
difference). 
Experiment No. 
Sodium 
cyanid 
(NaCN). 
Sulphuric 
acid 
(H 2 S0 4 ). 
Water 
(H 2 0). 
1 
Oz., avoir. 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
Fluid oz. 
3 
3 
3 
3 
3 
4 
4 
4 
4 
4 
5 
5 
5 
5 
6 
6 
6 
6 
Fluid oz. 
3 
4 
5 
6 
9 
4 
6 
8 
10 
12 
5 
71 
10 
15 
6 
8 
10 
12 
12.94 
17.58 
10.19 
7.48 
9.18 
1.44 
2.49 
4.36 
7.53 
8.14 
1.40 
4.04 
5.92 
9.91 
1.22 
2.74 
3.46 
5.00 
Per cent. 
87.06 
2 
82.42 
3.. 
89.81 
4 
92.52 
5 
90.82 
6. 
98.56 
7 
97.51 
8. .. 
95.64 
9 
92.47 
10 
91.86 
11 
98.60 
12. . 
95.96 
13 
94.08 
14 
90.09 
15 
98.78 
16 
97.26 
17 
96.54 
18 
95.00 
The following experiments were then made on samples of sodium 
cyanid of varying composition: No. 6524 contained 75.78 per cent of 
sodium cyanid and 14.20 per cent of sodium chlorid; No. 6525 con- 
tained 92.92 of sodium cyanid; and No. 6526 contained 75.18 per 
cent calculated as sodium cyanid and 5.82 per cent of sodium chlorid. 
Experiments with different samples of sodium cyanid. 
Experiment No. 
Amount of chemicals used. 
HCN remaining in residue 
(per cent of total). 
Sodium 
cyanid. 
Sulphuric 
acid. 
Water. 
No. 6524. 
No. 6525. 
No. 6526.1 
19 
Oz., avoir. 
3 
3 
3 
3 
3 
3 
3 
Fluid oz. 
. 3 
3 
3 
4 
4 
5 
6 
Fluid oz. 
3 
6 
9 
4 
6 
5 
6 
10.74 
7.68 
7.27 
.62 
1.65 
.39 
.24 
12.22 
8.16 
9.32 
3.16 
8.53 
20 
7.22 
21.. 
22 ; 
.80 
23 
3.21 
24 
1.73 
2.28 
.53 
25 
.58 
1 A mixture of sodium cyanid, potassium cyanid, and sodium chlorid. 
The acid acts very energetically on the sodium cyanid, and hy 
comparing the results with those obtained in previous work with 
potassium cyanid it is shown that less hydrocyanic acid remains in 
the residue when using sodium cyanid. It may be stated here that 
the very low results obtained with the impure cyanids Nos. 6524 and 
6526 are due to the decomposing action of hydrochloric acid, liberated 
from the sodium chlorid, on the hydrocyanic acid. When equal 
quantities of cyanid, acid, and water were used, there was not enough 
acid present to cause complete decomposition of the cyanid — decom- 
posed lumps of which always remained in the residue — nor was 
