PROPORTION OF WATEB AND Ailh. 25 
CHEMICALS. 
DEGREE OF PC KIT Y REQUIRED. 
The materials used in generating hydrocyanic-acid gas are potas- 
sium cyanid (KCN), sulphuric acid (H a S0 4 ), and water. The cyanid 
and acid should be purchased of a reliable dealer. The cyanid should 
be guaranteed to l>e 98 or 99 percent, which is practically chemically 
pure. The acid should be guaranteed to he 66° a and, as additional 
assurance, it would be well to have a sample tested by a druggist or 
by the fumigator himself by using an acid hydrometer. This instru- 
ment is inexpensive and can he obtained through any druggist. 
A linn or hard cyanid should be obtained rather than a. soft or 
porous product . 
HANOI. INC., AND NECESSITY FOR PROTECTION FROM MOISTURE. 
Potassium cyanid can be purchased in boxes of 200 pounds each. 
The cyanid readily absorbs moisture, and for this reason after a box 
is opened it should he kept constantly covered with burlap sacks and 
protected against rain when necessary. When only a few trees are 
to be treated and the box of cyanid is not to be completely used, 
within a few days at t he most, it is recommended that it be stored 
in large-sized tin cans with covers made practically air-tight by means 
of cheese cloth or muslin. The acid when used in large quantities is 
purchased in drums containing about 1,500 pounds. In smaller quan- 
tities it i^ sold in carboys containing a little less than 200 pounds. 
The carboys make convenient receptacles for handling in the groves. 
In emptying from a drum into carboys a large funnel of glass or 
sheet lead is useful. When the carboys are boxed and not other- 
wise provided with handles, strips of wood may be nailed along paral- 
lel sides projecting at each end, so as to make convenient handles 
For t wo men. If carboys can not be obtained or the quantity of acid 
used does not require temporary containers for such amounts, large 
jugs may he used. In all cases the containers, except when in use, 
should he stoppered. For this purpose wooden plugs, made tight 
w ith asbestos, such as can be bought in sheets from hardware dealers, 
may be used. When the acid is to be stored in carboys for more 
than a few days the plugs should be made extra tight by means of 
plaster of Paris. For water required in the generation of the gas 
anything that is reasonably clean will answer the requirements. 
PROPORTION OF WATER AND ACID. 
The proportion of the materials theorel ically required for a complete 
chemical reaction is I part of potassium cyanid, 1 part of acid, and 2 
parts of w ater. In pract ice 3 however, an excess of acid up to one-fourth 
a Sixty-six degrees sulphuric acid Is 93 per cent strength. 
