104 HYDROCYAXIC-ACID GAS FUMIGATION IX CALIFORNIA. 
SUMMARY. 
In order that the results may be more readily compared they are all 
presented in one table, as follows: 
Comparison of results obtained on evolution of hydrocyanic-acid gas under different 
conditions. 
Ex- 
peri- 
ment 
No. 
Material. 
Sodi- 
] um 
chlorid 
' in s am - 
' pie. 
Equiv- 
alent of 
HCX 
HCN in evolved, 
sample. 
HCN 
remain- 
ing in 
residue . 
HCN i Per cent 0I tot al HCX— 
deeom- 
posed ! 
(by dif- 
fer- Evolved, 
ence). . 
In resi- Deeom- 
due. j posed. 
1-5 
Sodium evanid 0. 00 
do../. 9.00 
do 16.66 
do 33.33 
do 50.00 
do 66.66 
Potassium eyanid .40 
Sodium eyanid 1-1. 20 
do .57 
do. 2 j 
Potassium evanid I 
do. 
Sodium eyanid (?) 2 , 
Per ct. Per ct. Per cent, 
9.00 
16. 
50.00 
6<d. 66 
51.82 
47.16 
43.18 
34.55 
25.91 
17.27 
40.42 
41.78 
51.22 
41.45 
39.96 
39.28 
41.02 
47.16 
43.18 
25.91 
17.27 
39.92 
37. 73 
21 22 
ia 12 
Per ct. 
1.4S 
1.71 
.37 
.05 
.10 
1.22 
1.32 
2.31 
2.04 
1.71 
1.40 
1.84 
Per ct. 
0.99 
4.54 
14. 05 
23.61 
25.91 
15.90 
1.25 
14.24 
.30 
2.48 
.74 
1.17 
4.01 
4.13 
3.fti 
95.23 
88.98 
63.49 
30.61 
22. 5S 
7.35 
93.88 
62.76 
94 32 
89.10 
93.87 
93.46 
So. 75 
84.66 
87.39 
SI. 51 
75.95 
2.S6 
1.40 
3.97 
1.06 
.21 
.63 
3.03 
3.17 
5.09 
4.92 
4.27 
2.67 
3.05 
4.40 
4.56 
1.91 
9.62 
32.54 
6s 33 
"7.21 
92.09 
3.09 
34.07 
.59 
5.98 
1.S6 
2.97 
9.76 
12.67 
9.56 
14.09 
19.49 
i Average of five determinations. 
2 A mixture of potassium and sodium eyanid and sodium chlorid. 
These experiments show conclusively that the presence of chlorids 
and nitrates in cyanids which liberate hydrochloric and nitric acid 
respectively, together with hydrocyanic acid, on treatment with 
sulphuric acid cause very marked decomposition of the hydrocyanic 
acid. The effect produced by hydrochloric acid is much more marked 
than that produced by nitric acid. In one case (experiment 10) 
over 92 per cent of the hydrocyanic acid was decomposed and only 
a little over 7 per cent evolved. This is a larger amount of sodium 
chlorid than would ever be found in a commercial sample, but it shows 
the important bearing this impurity has upon the results. Practi- 
cally all commercial potassium and sodium cyanids contain sodium 
chlorid in greater or less amount. Potassium eyanid is frequently 
sold as " 98-99 peiycent pure.'' which hi reality is a mixture of 
potassium eyanid, sodium eyanid. and sodium chlorid and on 
analysis may show even 100 per cent expressed as potassium eyanid 
yet there may be several per cent of sodium chlorid present. For 
fumigation work an analysis of a eyanid is of little value unless the 
chlorin content is also determined. In order that satisfactory results 
mav be" obtained hi the fumigation of trees for the control of insects 
