FUMIGATION OF CITRUS TREES. 49 
much of the liquid from the vessel. In one instance about 1 pound 
of cyanid was dissolved in water in a 2-gallon generator. Acid was 
then added, producing a disturbance so violent as to throw some of 
the liquid almost to the top of a 2-story barn. 
The cyanid should be in pieces anywhere from the size of an English 
walnut to that of a good-sized lemon. The smaller pieces should be 
used in the small dosages. Powdered cyanid should be avoided in so 
far as possible. Where purchased in large boxes there is always a 
considerable quantity of fine material at the bottom. Entire dosages 
for a tree should never be composed entirely of this character of 
cyanid or a violent reaction will take place, blowing much of the 
fine particles out of the generator and endangering the tent as well 
as the operator. This fine cyanid is most economically and satis- 
factorily disposed of by using it in small quantities along with lumps. 
The generation of gas has practically ceased at the expiration of 
from three to five minutes. 
Many writers on fumigation recommend the use of paper bags for 
holding each dosage when placed in the generating pot. These bags 
are used largely to retard the reaction so that the operator may 
retreat to some distance before the generation commences or else 
to prevent slopping. The writer's own experience, as well as some 
principles previously mentioned in this chemical discussion, would 
lead to advising against the use of paper bags. The retardation of 
generation is so marked in the case of small dosages in heavy paper 
bags that the amount of gas resulting must be considerably less 
than if the cyanid had been introduced in a free state. 1 By the exer- 
cising of a slight amount of care in introducing cyanid in the free 
state into a generating vessel there is no danger of the operator 
being affected by the gas or of the acid being slopped out. Neither 
will the generating pots boil over if the amounts scheduled on page 
24 are used. Fine or powdered cyanid should never be used in 
houses. In household work sheets of heavy paper should be placed 
underneath the generators. 
EFFECT OF THE PRESENCE OF SODIUM CHLOIJID ON THE AMOUNT OF 
GAS GIVEN OFF. 
Practically all commercial cyanid contains more or less common 
salt, technically known as sodium chiorid. The action of this salt 
in connection with fumigation demands consideration. It has been 
found, when sodium chiorid is present in the reaction of sulphuric 
acid on a cyanid in the production of hydrocyanic-acid gas, that 
this chiorid salt produces a secondary reaction which liberates an 
acid called hydrochloric acid, and that this liberated hydrochloric acid 
1 If paper sacks are employed, they should be of thin paper, or slit to allow the free action of the acid on 
the cyanid.— C. L. M. 
