8 CALIFORNIA CITRUS CULTURE. 
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Both of the cyanides are good and reliable, and the deciding features 
will probably always be the supply available and the price. 
Fic. 53.—The McFadden tent-hoisting machine. (After Woglum. ) 
Sulphuric Acid. Fumigating sulphuric acid has a specific gravity 
of about 66 degrees Baumé, often containing traces of nitric acid and 
arsenic, lead or zine. It has been the current belief that nitric acid 
especially caused the burning of the fruit and foliage so often the 
results of fumigating work, but R. S. Woglum in Bull. No. 90, Part I, 
page 42, U. 8. Dept. Agrel., Bureau Entomology, states that this is an 
erroneous belief. It should always be the aim of every fruit grower to 
get good grades of sulphuric acid, which is not at all difficult at the 
present time. 
CHEMICAL PROPORTIONS. 
Potassium Cyanide: 
Potassium cyanide ounce 
Sulphuric acid ________________ fluid ounce 
WEA C pe oo hee a te 2 ee Ee eee 3 fluid ounces 
Sodium Cyanide: 
Sodium cyanide 1 ounce 
Sulphuriciacid: ste ee Sh ee ee See 13 fluid ounces 
Weller 2o3 oes 22 es ee Beene ee ea i 2 
fluid ounces 
