SODIUM CYANID FOB FUMIGATION PURPOSES. 87 
1-11-2 formula. The dosage strength was equivalent to that of 
schedule No: 1 of potassium cyanid. The operation was carried out 
under the guidance of the foreman of the crew exactly as work is 
done by any commercial outfit. Several months later an examina- 
tion was made of a large number of trees located promiscuously 
throughout the orchard. Live purple scales were seen on only one of 
the trees examined, and on this much of the fruit was infested at the 
time of fumigation. This is the most successful work the writer has 
ever seen done by a practical outfit with gas of a strength equivalent 
to schedule No. 1 of potassium cyanid. 
Several hundred pounds of this high-grade sodium cyanid were used 
by another practical outfit in fumigating orange and lemon trees. 
These fumigators were as satisfied with this cyanid as with the regu- 
lar potassium cyanid. 
From the results of field work in this investigation it has been found 
that the use of a high-grade, or almost chemically pure, sodium cyanid 
produced exactly as perfect a generation of gas in all cases as the use 
of a similar grade of potassium cyanid; in the majority of cases where 
used the generation was apparently superior to that from a potassium 
cyanid. - 
ACTION OF SODIUM CHLORID. 
The above recommendations are for a high-grade sodium cyanid— 
one almost 133 per cent pure. Experience in California with a 98 
to 100 per cent sodium cyanid has proved unsatisfactory. The rea- 
son is given herewith. Chemical analyses have shown that practi- 
cally all commercial potassium and sodium cyanids contain more or 
less common salt, which is technically spoken of as sodium chlorid. 
Newell, 1 in 1905, pointed out that sodium chlorid, when present in 
the reaction producing hydrocyanic-acid gas, causes a secondary 
reaction which liberates an acid called hydrochloric acid, and that 
this liberated hydrochloric acid immediately attacks the hydrocyanic- 
acid gas, decomposing it to a great extent. In order to ascertain more 
thoroughly the status of this salt Mr. McDonnell carried on a large 
amount of experimental work. These results not only showed con- 
clusively that the presence of sodium chlorid results in a decom- 
position of the hydrocyanic-acid gas, but also that if a sufficiently 
large percentage of sodium chlorid is present the decomposition will 
be so great as to result in little if any hydrocyanic-acid gas. The 
conclusion to be drawn from these experiments is that the cyanids 
suitable for fumigation work should be practically free of sodium 
chlorid. 
The serial numbers 6523-6529 in the table on page 92, Part III of 
this bulletin, are samples of cyanids which have been used to some 
i Bui. 15, Ga. State Bd. of Ent,, 1905. 
67330°— Bull. 90—12 7 
