ARSENATE OF LEAD 197 



that it be good, hard rock lime and not air-slaked lime, since 

 the heat for cooking is to come entirely from the lime. On top 

 of the lime place the sulfur. Then add hot water slowly until 

 the lime is slacked, stirring carefully, as needed, to prevent the 

 "burning" of the lime. After slacking is complete allow the 

 mixture to stand and cook for fifteen minutes, keeping the 

 barrel covered with an old burlap to keep in the heat. Then 

 add enough water to make 50 gallons, strain into the spraying 

 cask and apply at once. Remember this is merely a summer 

 fungicide and has no value for San Jose scale and relatively 

 little as a dormant fungicide. 



Soluble Sulfur. At the present time the most interesting 

 of the special forms of sulfur on the market is known as "soluble 

 sulfur." It comes in rather coarse granules which dissolve 

 readily in water. If further experiments shall show that it is 

 efficient under all conditions and does not injure foliage it ought 

 to prove a valuable form. 



"Atomic sulfur'' is a second form. This is a very finely 

 divided form of pure sulfur which seems promising, but at the 

 present writing needs further testing. 



INSECTICIDES 



There are two general classes of insecticides: The food- 

 poisons, which are used for chewing insects and are usually 

 some form of arsenic; and the contact sprays used for sucking 

 insects. 



In the first of these classes, at the present time, the arsenate 

 of lead is used much more generally than any bther form, with 

 Paris green as a second. Several others are on the market and 

 are used to a limited extent, but from the commercial orchard 

 standpoint they may be ignored. 



Arsenate of Lead. The great advantages- of arsenate of lead 

 are (1) that it is very adhesive, remaining on the leaves through 

 the entire season; (2) that it is finely divided, remaining in sus- 

 pension much longer than Paris green; and (3) that it is usually 

 harmless to foliage. This is a strong combination and it is small 

 wonder that arsenate of lead is so generally used. It is, how- 



