78 



CALIFORNIA CITRUS CULTURE. 



Both of the cyanides are good and reliable, and the deciding features 

 will probably always be the supply available and the price. 



FIG. 53. The McFadden tent-hoisting machine. (After Woglum.) 



Sulphuric Acid. Fumigating sulphuric acid has a specific gravity 

 of about 66 degrees Baume, often containing traces of nitric acid and 

 arsenic, lead or zinc. 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. S. Dept. Agrcl., 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 _______________________________ . __ 1 



Sulphuric acid _____________________________________ 1 



Water _____________________________ _______________ 3 



Sodium Cyanide: 



Sodium cyanide ____________________________________ 1 



Sulphuric acid _____________________________________ 1 



Water _ ____ 2 



ounce 



fluid ounce 

 fluid ounces 



ounce 



fluid ounces 



fluid ounces 



