228 
tained by always bearing in mind үч) "od of a given mee of 
tassium cyanide is cyanogen. s if a certain bran cyanide 
contains 24 per cent. of vot iai и. is equivalánt to 60 péi cent. of 
pure potassium cyanide. Potassium cyanide when absolutely pure 
n 
than this. 
“ The potassium oyanidé used =ч m" ти hydrocyanie acid gas 
is principally manufactured by two fir Po Weight am ө 
Philadelphia, Pa., and the Mallinkrodt Chemical Works, of "St. Lo 
Mo. ia made vi the first named firm is the most largely mrs 
when purchased by the ton € priee is 36 cents per pound for the grade 
containing about 5 per cent. of pure potassium cyanide, packages and 
carriage extra. It is put dp à in tin cans holding 10 pounds each, and 
also in barrels holding about 400 pounds each. That in the caus is 
much to be preferred, since the quantity in each is so small that it will 
soon be used up after the can is opened ; whereas, the barrel containing 
so large a quantity, the cyanide asd towards the last will have lost 
much of its strength by contact with the air. It is customary to weigh 
out the cyanide in small paper parcels, and mark each parcel with 
the number of ounces of cyanide that it contains; vy when the tree is 
to be fumigated it is an easy matter for the operator to select one of the 
containing a sufficient quantity of the cyanide for the tree, thus 
о 
each tree. As the fumigating is done only at night the weighing of 
the лт is та done by de ladies of the house upon the day 
Apre cdi its 
: “The antity of cyanide to be used on each tree will, of course, 
depend not dais on the size of the tree but also on the strength of the 
cyanide used. The following table will aid in determining the proper 
quantity of each ingredient to be used on different sized citrus trees, the 
cyanide being about 58 per cent. pure :— 
" Diameter of š š ium 
Height of Tree. | р. top. Water. Sulphuric Acid. [err d. 
—— | io C s 
Il Feet. Fluid y Fluid ozs. Ounces. 
4 : 
Я 8 6 2 A. X 
0 8 41 2 2 
12 10 8 : 1 Py 
12 14 16 8 8 
14 10 10 5 
14 14 19 91 91 
16 12 16 8 8. 
16 16 29 14 14} 
18 14 26 13 13 
16 36 18 18 
23 18 52 26 26 
24 20 66 33 Ш” 
This treatment is rot only fatal to Aspidiotus аиташи, but also to 
any other scale insects which — на found оп the orange, and to 
numerous other insects. The gas i course poisonous = тап апа 
other animals, and care — be ret in using it. 
time it has been used in a very extensive scale in California, fully 
20,000 trees were treated in Orange County alone in 1890; and Mr. 
